102
■■CharSet missing or incomplete for Type 1 font: A font is
not fully embedded and contains no list of embedded sym-
bols (CharSet). If a font in Type 1 format is not fully embed-
ded, it must contain a list of the embedded characters to en-
able conversion to PDF/A 周e list must include all characters
used in this font in the PDF file. In this case, a font is not
fully embedded in this PDF file and its list of embedded sym-
bols is missing or is incomplete. Remedy: In order to resolve
this problem, the PDF file must be created again using a dif-
ferent font or with the same font but in its complete form.
Alternatively, the incomplete font may be used, but only with
the relevant CharSet.
■■CIDset in subset font is incomplete: A font is not fully
embedded and contains no list of embedded symbols (Char-
Set). If a font in CID 1 format is not fully embedded, it must
contain a list of the embedded characters to enable conver-
sion to PDF/A. 周e list must include all characters used in
this font in the PDF file. In this case, a font is not fully embed-
ded in the PDF file and its list of embedded characters is in-
complete. Remedy: In order to resolve this problem, the PDF
file must be created again using a different font or with the
same font but in its complete form. Alternatively, the incom-
plete font may be used, but only with the relevant CharSet.
■■CIDset in subset font missing: A font is not fully embed-
ded and contains no list of embedded symbols (CharSet). If a
font in CID 1 format is not fully embedded, it must contain a
list of the embedded characters to enable conversion to
PDF/A. In this case, a font is not fully embedded in the PDF
file but the list of embedded characters is missing. Remedy: In
order to resolve this problem, the PDF file must be created
again using a different font or with the same font but in its
complete form. Alternatively, the incomplete font may be
used, but only with the relevant CharSet.
■■CIDSystemInfo and CMap dict not compatible: A font is
not fully embedded and contains no list of embedded sym-
bols (CharSet). 周e characters stored in a font are allocated
number codes in accordance with an allocation table. 周ese
number codes are used to display the characters in the PDF
that uses them. No allocation table has been specified for a
font in this PDF. Remedy: In order to resolve this problem,
the PDF file must be created again using a different font or
with the same font but in its complete form. Alternatively,
the incomplete font may be used, but only with the relevant
CharSet.
■■CMap not embedded for custom CMap: A font is not
fully embedded and contains no list of embedded symbols
(CharSet). 周is font has no clear information regarding the
assignment of characters to letters (the CMap is missing). 周e
letters and other characters used in PDF texts require ‘fonts’
that determine their exact appearance when visualized. 周e
characters stored in a font are allocated number codes in ac-
cordance with an allocation table. 周ese number codes are
used to display the characters in the PDF that uses them.
周ese allocation tables are made up differently depending
upon the font format (PostScript Type 1, Type 3, or TrueType)
and are known as ‘encodings’. MacRoman (Macintosh) and
WinAnsi (Windows) are standard encodings. ‘CID fonts’ can
use encodings that deviate from these standards. 周e PDF/A
standard stipulates that a font that uses its own encoding
must get the encoding in question from a corresponding table
(CMap). 周is PDF does not use standard encoding and does
not contain an encoding table (CMap). 周is PDF can there-
fore not be converted to PDF/A. Remedy: In order to resolve
this problem, the PDF file must be created again using a dif-
ferent font or with the same font but in its complete form.
Alternatively, the incomplete font may be used, but only with
the relevant CharSet.
■■CMYK used but PDF/A OutputIntent not CMYK: Device-
dependent color (DeviceCMYK), but no CMYK output intent.
Because the PDF/A standard stipulates that colors must appear
the same (as far as is technically possible) regardless of the out-
put device, either a PDF/A document must only contain de-
vice-neutral colors or the color properties of the output device
must be defined using an output intent profile. If a document
contains DeviceRGB or DeviceCMYK colors, an output intent
of the same type must therefore exist. Remedy: Preflight con-
tains a correction option that converts the alternate visualiza-
tion to CMYK (SWOP). 周is correction must be duplicated
and an RGB color space such as sRGB must be used as the tar-
get. 周e correction can then be assigned to a profile. 周e alter-
nate visualization of the spot color can then be modified. pd-
faPilot also solves this problem.
■■CMYK used for alt. color but PDF/A OutputIntent not
CMYK: A spot color has been defined in DeviceCMYK but
the output intent is not defined for CMYK. Because the
PDF/A standard stipulates that colors must appear the same
(as far as is technically possible) regardless of the output de-
vice, either a PDF/A document must only contain device-
neutral colors or the color properties of the output device
must be defined using an output intent profile. If a document
contains DeviceRGB or DeviceCMYK colors, an output in-
tent of the same type must therefore exist. Remedy: Preflight
contains a correction option that converts the alternate visu-
alization to CMYK (SWOP). 周is correction must be dupli-
cated and an RGB color space such as sRGB must be used as
the target. 周e correction can then be assigned to a profile.
周e alternate visualization of the spot color can then be mod-
ified. pdfaPilot also solves this problem.
70
PDF/A
in a Nutshell
What the Preflight error messages mean
99
■■Compressed object streams used: Since PDF 1.5, which
Adobe introduced with Acrobat 6, some objects in PDF files
can be compressed as object streams. 周is technique is used
in this PDF. 周e PDF/A standard only permits objects that
are compatible with PDF 1.4. Cross-object compression is
therefore not permitted in PDF/A files. Remedy: Use the Ac-
robat PDF Optimizer to save the file as a PDF 1.4 file.
■■Contains action of type ImportData: Active content that
imports data from an external file. PDF files can dynamically
alter their content during visualization. Actions can be con-
tained in the PDF file for this purpose. 周e PDF/A standard
stipulates that the visualization of a document must be guar-
anteed and always the same. For this reason, active content is
not permitted in PDF/A files. 周e only exception is elements
for page navigation. Remedy: 周e PDF must be redesigned
and generated again so that all content is present within the
file itself.
■■Contains action of type Launch: Active content that trig-
gers another application. PDF files can dynamically alter
their content during visualization. Actions can be contained
in the PDF file for this purpose. 周is PDF file contains an ac-
tion for launching another application. 周e PDF/A standard
stipulate that the visualization of a document must be guar-
anteed and always the same. For this reason, active content is
not permitted in PDF/A files. 周e only exception is elements
for page navigation. Remedy: 周e PDF must be redesigned
and generated again so that all content is present within the
file itself.
■■Contains action of type Movie: Active content that shows
a movie in another window. PDF files can dynamically alter
their content during visualization. Actions can be contained
in the PDF file for this purpose. 周is PDF file contains an ac-
tion for playing a movie. 周e PDF/A standard stipulates that
the visualization of a document must be guaranteed and al-
ways the same. For this reason, active content is not permit-
ted in PDF/A files. 周e only exception is elements for page
navigation. Remedy: 周e Acrobat PDF Optimizer contains
an option called ‘Discard all comments, forms and multime-
dia’ that can be used to remove movies.
■■Contains action of type ResetForm: Active content that
influences the content of form fields. PDF files can dynami-
cally alter their content during visualization. Actions can be
contained in the PDF file for this purpose. 周is PDF file con-
tains an action for emptying form fields (ResetForm). 周e
PDF/A standard stipulates that the visualization of a docu-
ment must be guaranteed and always the same. For this rea-
son, active content is not permitted in PDF/A files. 周e only
exception is elements for page navigation. Remedy: 周e Acro-
bat PDF Optimizer contains an option called ‘Discard all
form submission, import and reset actions’ that corrects this
problem.
■■Contains action of type Sound: Contains audio data
(sound). PDF files can dynamically alter their content during
visualization. Actions can be contained in the PDF file for
this purpose. 周is PDF file contains an action for playing
sound. 周e PDF/A standard stipulates that the visualization
of a document must be guaranteed and always the same. For
this reason, active content is not permitted in PDF/A files.
周e only exception is elements for page navigation. Remedy:
周e Acrobat PDF Optimizer contains an option called ‘Dis-
card all comments, forms and multimedia’ that can be used
to remove audio data.
■■Creation Date mismatch between Document Info and
XMP metadata: 周e ‘CreateDate’ entry in the XMP docu-
ment information deviates from the ‘Created’ entry in the
document properties. 周e PDF/A standard stipulates that
document information must exist in the XMP area. If this
data is also contained in the document properties, it must be
identical to the entries in the XMP area. Remedy: A PDF file
can contain descriptive document information including the
author, creation date, title, and other details. 周is informa-
tion can be opened using the ‘File’ menu and changed in the
general Document Properties dialog. Otherwise, the PDF/A
file can be recreated from scratch.
■■Creator mismatch between Document Info and XMP
metadata: 周e ‘PDF creator’ entry in the XMP document in-
formation deviates from the corresponding entry in the doc-
ument properties. 周e PDF/A standard stipulates that docu-
ment information must exist in the XMP area. If this data is
also contained in the document properties, it must be identi-
cal to the entries in the XMP area. Remedy: New PDF/A con-
version.
■■Custom annotation used: A comment in the PDF docu-
ment does not use a standard PDF comment type. 周e PDF
specification allows PDFs to contain comments in custom
formats. 周is function can be used in specialized applications
to position special, additional elements in PDF files. 周ese
comments much have the comment type ‘Custom’. Use is sel-
dom made of these options. Because custom comments can
only be visualized on specialized output devices, they may
not be used in PDF/A files. Remedy: 周ese comments must be
discarded.
■■Destination profiles in OutputIntents differ: 周ere are
multiple output intents with different profiles. Because the
PDF/A standard stipulates that colors must appear the same
What the Preflight error messages mean
PDF/A
in a Nutshell
71
101
(as far as is technically possible) regardless of the output de-
vice, either a PDF/A document must only contain device-
neutral colors or the color properties of the output device
must be defined using an output intent profile. If a document
contains DeviceRGB or DeviceCMYK colors, an output in-
tent of the same type must therefore exist. 周e output intent
must describe the color properties of the output device using
an ICC profile. To ensure unambiguity, a PDF/A file may only
have different output intents if all of the output intents used
have the same ICC profile. Remedy: Preflight contains a cor-
rection option that converts the alternate visualization to
CMYK (SWOP). 周is correction must be duplicated and an
RGB color space such as sRGB must be used as the target. 周e
correction can then be assigned to a profile. 周e alternate vi-
sualization of the spot color can then be modified. pdfaPilot
can also carry out this task.
■■Device process color used but no PDF/A OutputIntent:
Device-dependent color exists, but no output intent. Because
the PDF/A standard stipulates that colors must appear the
same (as far as is technically possible) regardless of the output
device, either a PDF/A document must only contain device-
neutral colors or the color properties of the output device
must be defined using an output intent profile. If a document
contains DeviceRGB or DeviceCMYK colors, an output in-
tent of the same type must therefore exist. Remedy: Preflight
contains a correction option that converts the alternate visu-
alization to CMYK (SWOP). 周is correction must be dupli-
cated and an RGB color space such as sRGB must be used as
the target. 周e correction can then be assigned to a profile.
周e alternate visualization of the spot color can then be mod-
ified. pdfaPilot can also carry out this task.
■■Device process color used in alt. color space but no
PDF/A OutputIntent: A spot color has been defined as a de-
vice color, but no output intent exists. Because the PDF/A
standard stipulates that colors must appear the same (as far
as is technically possible) regardless of the output device, ei-
ther a PDF/A document must only contain device-neutral
colors or the color properties of the output device must be
defined using an output intent profile. If a document contains
DeviceRGB or DeviceCMYK colors, an output intent of the
same type must therefore exist. Remedy: Preflight contains a
correction option that converts the alternate visualization to
CMYK (SWOP). 周is correction must be duplicated and an
RGB color space such as sRGB must be used as the target. 周e
correction can then be assigned to a profile. 周e alternate vi-
sualization of the spot color can then be modified. pdfaPilot
can also carry out this task.
■■Document contains JavaScripts: Active content in the
form of JavaScript changes the visualization of pages. PDF
files can dynamically alter their content during visualization.
周is active content can be contained in PDF files in the form
of JavaScript, for example. 周is is the case in this PDF.
JavaScript is o晴en used in connection with active form ele-
ments (for example, buttons). 周e PDF/A standard stipulates
that the visualization of a document must be guaranteed and
always the same. For this reason, active content is not permit-
ted in PDF/A files. Remedy: 周e Acrobat PDF Optimizer con-
tains the ‘Discard all JavaScript actions’ option in the ‘Dis-
card Objects’ area. 周is option can be used to correct the
error.
■■Document is damaged and needs repair: 周e PDF file is
incorrectly formatted. Every PDF/A file must be a basically
correct PDF file. 周e file that is currently open does not con-
form with the PDF specification and can therefore not be
converted to PDF/A. Remedy: 周e problem can possibly be
resolved by opening the file in Adobe Acrobat and saving it
once again using the ‘Save As’ option. Otherwise, it might be
possible to clean it up using the ‘Save Optimized As’ option.
■■Document is encrypted. 周e document is encrypted and
cannot be analyzed. PDF files can be encrypted in order to
password-protect certain functions. 周is means that a PDF
can be displayed on the monitor without restrictions but a
password is required in order to print or modify it. Encryp-
tion is not permitted in a PDF/A file, as its visualization would
then be dependent upon information stored externally (i.e. a
password). Remedy: 周e PDF file cannot be converted to
PDF/A in this form. If the required password is known, the
PDF file’s password protection can be removed in Adobe Ac-
robat and the file can then be saved.
■■Embedded PostScript operator: 周e document uses
PostScript code for the page description. PostScript code can
also be used in PDF files. 周is option was primarily used at
the beginning of the PDF format era by programs that did not
offer full PDF support. However, there are very few programs
that can visualize this PostScript code on a monitor. Post-
Script code is used in this PDF document to describe the page
objects. Because the PDF/A standard stipulates that all com-
ponents of a PDF file must be reliably visualized, the use of
PostScript code is not permitted in PDF/A files. Remedy: 周is
error occurs very rarely. Current PDF-to-PDF/A converters
solve this problem during the conversion process by removing
the PostScript entries.
■■EmbeddedFiles entry in Names dictionary: 周e docu-
ment contains an embedded file. In PDF files, other files can
be embedded as an ‘attachment’ in a similar manner as with
an e-mail. 周e corresponding program is required to view
these files (for example, Microso晴 Word if a Word file is em-
72
PDF/A
in a Nutshell
What the Preflight error messages mean
99
bedded). Because the PDF/A standard stipulates that it must
be possible to visualize all components of a PDF file without
the aid of other so晴ware, file attachments are not permitted
in PDF/A files. Remedy: 周e Acrobat PDF Optimizer con-
tains an option called ‘Discard file attachments’ in the ‘Dis-
card Objects’ area. 周is option corrects the error.
■■Encoding entry prohibited for symbolic TrueType font:
周is symbol font contains an allocation table for ‘normal’
fonts. 周e PDF/A standard stipulates that a TrueType font
that is also a symbol font may not use an entry for this type of
standard encoding, since standard encoding only defines
‘normal’ characters and not the special characters contained
in symbol fonts. 周is PDF can therefore not be converted to
PDF/A. Remedy: In order to resolve this problem, the PDF file
must be created anew, using a different font.
■■File header not compliant with PDF/A: 周e PDF file
header (PDF version entry or binary digit string) is not com-
pliant. 周e PDF/A standard stipulates that a PDF file must
comply with the general file header regulations in the PDF
specification (1.6). Remedy: 周e ‘Save As’ command in Acro-
bat can be used to solve this problem.
■■File size is above 2GB: 周e file is too large (the maximum
permitted size is 2GB). Extremely large files may lead to ren-
dering problems when the files in question are printed out or
displayed on a monitor. 周e maximum file size is therefore
limited to 2 GB in the PDF/A standard. Remedy: No repair
possible. It may be possible to recreate the PDF file with a
more effective compression type.
■■Font not embedded (and text rendering mode not 3):
Text uses a non-embedded text. 周e letters and other charac-
ters used in PDF texts require ‘fonts’ that determine their ex-
act appearance when visualized. A text in this PDF uses a
font that is not embedded into the PDF. It is therefore only
possible to visualize this PDF correctly if this font is installed
on the computer or printer being used. Because PDF/A stipu-
lates that a PDF may not require external dependencies in
order to be visualized, PDF/A files must not contain any fonts
that are not embedded. 周e only exception is text that is not
displayed but is merely used for the full-text search instead
(text rendering mode = 3). Remedy: 周e PDF must be regen-
erated with all used fonts embedded.
■■Form field does not have appearance dict: Form field is
‘invisible’: A PDF file can contain form fields. 周ese form
fields must contain additional information to ensure that
they can be visualized. 周is PDF contains form fields that do
not contain the required additional information. Because the
PDF/A standard stipulates that the visualization of a docu-
ment must be guaranteed and that it must be identical when
output on a printer and when displayed on a monitor, a PDF/A
document must only contain form fields with a visual repre-
sentation. Remedy: 周e Acrobat PDF Optimizer contains an
option called ‘Discard all comments, forms and multimedia’
that can be used to remove form fields.
■■Form field’s AP (appearance) contains only N entry is
not true: Form fields in PDF files can contain differing visu-
alization methods that are used, for example, depending on
whether the mouse cursor is moved over a form field or the
form field is clicked. 周ese effects are, of course, not possible
when a document is output on a printer. Because the PDF/A
standard stipulates that the visualization of a document must
be guaranteed and that it must appear identical when output
on a printer and when displayed on a monitor, form fields in
a PDF/A document may not have different visualization vari-
ants for mouse effects. Remedy: 周e Acrobat Professional
PDF Optimizer has an option called ‘Discard all comments,
forms and multimedia’ in the ‘Discard User Data’ area. 周is
option corrects this error.
■■Glyphs missing in embedded font: A font does not con-
tain all of the characters required. 周e letters and other char-
acters used in PDF texts require ‘fonts’ that determine their
exact appearance when visualized. 周is PDF contains an em-
bedded font, in which however not all symbols that are used
in texts using this font, are described. 周is means that there
is no visual representation for the characters that are missing.
周e PDF/A standard stipulates that all fonts used must be
embedded and that a visual representation for all used char-
acters must exist. 周is PDF can therefore not be converted to
PDF/A. Remedy: To resolve this problem, the PDF file must be
created anew.
■■ICC profile version 4 or newer: 周is file uses an ICC pro-
file for color definition that has a newer version than is per-
mitted by PDF/A. 周e file can therefore not be converted to
PDF/A. 周e ICC profile may also be defective. Remedy: Note
that it is very unusual for ICC profiles that are more recent
than Version 3 to be used. Tools such as the Acrobat Preflight
module can be used to find out which component uses the
profile in question. 周is enables the error to be eliminated.
周e object in question must be recreated and the PDF file
must then be regenerated.
■■ID in file trailer missing or incomplete: No file ID entry
available. Every PDF file should contain an internal ID that
gives it a certain uniqueness and is altered each time the doc-
ument is changed. 周e PDF/A standard requires the presence
of this ID. Remedy: 周e ‘Save As’ command in Acrobat can
be used to solve this problem.
What the Preflight error messages mean
PDF/A
in a Nutshell
73
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101
■■Image has OPI information: OPI (Open Prepress Inter-
face) is a procedure used in prepress. It involves the replace-
ment of images with alternate images when printing via an
OPI server. Since PDF files that carry OPI information can
give different results depending on the output chosen (dis-
play on a monitor, printing on a desktop printer, or printing
via an OPI server), OPI comments are not permitted in PDF/A
files. Remedy: OPI comments can be removed using the Acro-
bat PDF Optimizer.
■■Inadequate namespace URI for PDF/A entry: 周e PDF/A
entry in the document information is incorrectly formatted.
A PDF/A file must have a corresponding entry in its docu-
ment information. 周is entry can also be displayed with Ado-
be Acrobat. To display it, the user must choose ‘Properties’
from the ‘File’ menu in Adobe Acrobat and then click the ‘Ad-
ditional Metadata...’ button. 周e entry appears in the ‘Ad-
vanced’ section under http://www.aiim.org/pdfa/ns/id/. 周e
PDF entry is available in this document but it is incorrectly
formatted. Remedy: New PDF/A conversion.
■■Incorrect PDF/A version number (must be 1): 周e PDF/A
entry in the document information is incorrectly formatted
(version number is not ‘1’). A PDF/A file must have a corre-
sponding entry in its document information. 周is entry can
also be displayed with Adobe Acrobat. To display it, the user
must choose ‘Properties’ from the ‘File’ menu in Adobe Acro-
bat and then click the ‘Additional Metadata...’ button. 周e
entry appears in the ‘Advanced’ section under http://www.
aiim.org/pdfa/ns/id/. 周is group must contain a ‘pdfaid:part:
“1” entry. 周is entry specifies the version of the PDF/A stan-
dard. In this PDF file, the entry has a value that is not equal to
‘1’. Remedy: New PDF/A conversion.
■■Incorrect PDF/A-1a conformance level (must be “A”):
周is message only appears when validating PDF/A-1a (and not
when validating PDF/A-1b). 周e PDF/A entry does not have the
compliance level PDF/A-1a. A PDF/A file must have a corre-
sponding entry in its document information. 周is entry can
also be displayed with Adobe Acrobat. To display it, the user
must choose ‘Properties’ from the ‘File’ menu in Adobe Acro-
bat and then click the ‘Additional Metadata...’ button. 周e en-
try appears in the ‘Advanced’ section under http://www.aiim.
org/pdfa/ns/id/. 周is group must contain a ‚pdfaid:conformance:‘
entry that specifies ‘A’ and declares that the file must comply
with PDF/A-1a (and not ‘only’ with PDF/A-1b). PDF/A-1a files
are always compliant with PDF/A-1b. Remedy: Preflight can
correct this entry if converting the file to PDF/A-1a.
■■Incorrect PDF/A-1b conformance level (must be “B”):
周e PDF/A entry does not have the compliance level PDF/A-
1b. A PDF/A file must have a corresponding entry in its docu-
ment information. 周is entry can also be displayed with
Adobe Acrobat. To display it, the user must choose ‘Proper-
ties’ from the ‘File’ menu in Adobe Acrobat and then click the
‘Additional Metadata...’ button. 周e entry appears in the ‘Ad-
vanced’ section under http://www.aiim.org/pdfa/ns/id/. 周is
group must contain a ‘pdfaid:conformance:’ entry that speci-
fies ‘A’ or ‘B’ and declares that the file must comply with either
PDF/A-1a or PDF/A-1b. PDF/A-1a files are always compliant
with PDF/A-1b. 周is PDF contains a conformity entry, but it
is not B or A. Remedy: Preflight can correct this entry.
■■Interpolate key for image not false: An image has an
‘interpolation key’ that is not supported by PDF/A viewers.
周e rendering or printout of an image is based upon the reso-
lution of the output device. 周is means that it depends on the
vertical or horizontal resolution if a monitor is being used
and on the thickness of the lines with which the printing
drum can be ‘imaged’ if a laser printer is being used. If the
image resolution is significantly less than the resolution of
the output device, additional pixels must be added. 周is pro-
cess is known as interpolation. Interpolation is normally car-
ried out in accordance with a standard procedure. However,
an image in a PDF file can contain a key stating that a par-
ticular interpolation procedure must be used. Nevertheless,
this option is rarely used these days and the key is ignored by
most output devices. Because PDF/A files must appear the
same regardless of the output device used, images in PDF
files may not have interpolation keys. Remedy: PDF-to-PDF/A
tools such as Preflight or pdfaPilot have correction functions
that make files containing interpolation keys standard-com-
pliant.
■■Invalid rendering intent: Only the following standard
rendering intents are permitted in PDF/Afiles: Relative Color-
metric, Absolute Colormetric, Perceptual, and Saturation. It
is very unusual for a different rendering intent to be specified
in a PDF. However, this PDF uses a different rendering intent.
Remedy: 周is is a very unusual error. It can be corrected us-
ing pdfaPilot.
■■Invalid WMode: 周e stream direction is entered incor-
rectly in this font. 周e letters and other characters used in
PDF texts require ‘fonts’ that determine their exact appear-
ance when visualized. In addition to the appearance of the
characters, a font must contain information regarding the
font ‘stream direction’, since the characters of a font may not
always be strung together horizontally from le晴 to right as is
the case with Latin fonts. For example, some Far Eastern
fonts characters are strung together in a vertical direction
(from top to bottom). 周is PDF uses a font with incorrect
stream direction information. It is therefore impossible to
ensure that the PDF will always be visualized in exactly the
74
PDF/A
in a Nutshell
What the Preflight error messages mean
100
same way regardless of the output device. 周is PDF cannot be
converted to PDF/A. Remedy: 周is problem can be avoided
by using a different font for the text in question.
■■JPEG2000 compression used: An image in this docu-
ment is compressed in JPEG2000. Images placed in a PDF are
usually compressed to keep the size of the PDF file to a mini-
mum. Various compression methods such as ZIP, LZW, and
JPEG can be used to compress image data. Images com-
pressed using JPEG2000 can be decompressed in stages dur-
ing visualization, meaning that an image can be displayed
even if it is not fully decompressed. However, this process is
only supported in more recent PDF versions and must not be
used in PDF/A files. 周e PDF/A standard does not support
objects that were not permitted in the PDF 1.4 specification
that was published by Adobe with Acrobat 5. Remedy: 周e
Acrobat PDF Optimizer can be used to apply JPEG or ZIP
compression (without downsampling) to all images. Alterna-
tively, the file can be saved as a PDF 1.4 file.
■■Keyword mismatch between Document Info and XMP
metadata: 周e ‘Keywords’ entry in the XMP document in-
formation deviates from the corresponding entry in the doc-
ument properties. 周e PDF/A standard stipulates that docu-
ment information must exist in the XMP area. If this data is
also contained in the document properties, it must be identi-
cal to the entries in the XMP area. Remedy: New PDF/A con-
version.
■■Last Modification Date mismatch between Document
Info and XMP Metadata: 周e ‘ModifyDate’ entry in the
XMP document information deviates from the correspond-
ing entry in the document properties. 周e PDF/A standard
stipulates that document information must exist in the XMP
area. If this data is also contained in the document proper-
ties, it must be identical to the entries in the XMP area. Rem-
edy: 周e ‘Save As’ command in Acrobat can be used to solve
this problem.
■■Layers used: 周e file contains layers that can be used to
switch the visibility of objects on and off. Layers can be used
in PDF files to define that certain page content should only be
visualized under certain circumstances. Whether or not an
object placed on a layer is visible depends on whether the
viewer has set the layer in question to ‘visible’ or ‘invisible’. (It
is also possible for visibility of a layer to be linked to other
factors such as the zoom level with which a PDF is viewed –
in this case, very small details in a drawing might only be
visible when using a large zoom value.) Because PDF/A stipu-
lates that the visual appearance of a PDF must always be ex-
actly the same, layers cannot be used in PDF/A files. Remedy:
周e Acrobat PDF Optimizer ‘Discard hidden layer content
and flatten visible layers’ option or the Preflight ‘Merge Lay-
ers’ option can be used to correct this error.
■■LZW compression used: Objects used in a PDF are o晴en
compressed to keep the size of the PDF file to a minimum.
Various compression methods are permitted for doing this,
including ZIP, LZW, and JPEG (for images). 周is PDF file
uses LZW compression. LZW compression is a lossless com-
pression method that is patented. It can quite easily be re-
placed by ZIP compression, which is also lossless and uses a
similar algorithm but is not patent-protected. 周e PDF/A
standard only permits objects that can be visualized without
restriction, even in the future. 周is also includes legal restric-
tions that might exist because of the LZW patent. For this
reason, LZW compression is not permitted in PDF/A files.
Remedy: 周e Acrobat PDF Optimizer contains an option
that can be used to apply JPEG or ZIP compression (without
downsampling) to all images in the ‘Images’ section.
■■Marked entry in MarkInfo missing: 周is message only
appears when validating PDF/A-1a (and not when validating
PDF/A-1b). 周e document does not contain any information
on its structure (in the document catalog). 周e stricter PDF/
A-1a standard stipulates that a PDF file must contain struc-
tural information. Remedy: To resolve this problem, the PDF
file must be given the relevant structural information. 周is
information can be added when the PDF is generated. Some
PDF export modules have a ‘Tagging’ option or an option
with a similar name. 周is enables structural information to
be transferred into a PDF. It is also possible to add structural
information later on in Adobe Acrobat Professional. Alter-
natively, it might be possible to convert the file to PDF/A-1b
instead.
■■Marked entry in MarkInfo not boolean: 周is message
only appears when validating PDF/A-1a (and not when vali-
dating PDF/A-1b). 周e document contains no correctly for-
matted information on its structure. 周e stricter PDF/A-1a
standard stipulates that a PDF file must contain structural
information. Remedy: To resolve this problem, the PDF file
must be given the relevant structural information. 周is in-
formation can be added when the PDF is generated. Some
PDF export modules have a ‘Tagging’ option or an option
with a similar name. 周is enables structural information to
be transferred into a PDF. It is also possible to add structural
information later on in Adobe Acrobat Professional. Alter-
natively, it might be possible to convert the file to PDF/A-1b
instead.
■■Marked entry in MarkInfo not set to true: 周is message
only appears when validating PDF/A-1a (and not when validat-
ing PDF/A-1b). 周e entry for structural information is defined
What the Preflight error messages mean
PDF/A
in a Nutshell
75
98
as ‘not available’ in the document. 周e stricter PDF/A-1a stan-
dard stipulates that a PDF file must contain structural infor-
mation. Remedy: To resolve this problem, the PDF file must be
given the relevant structural information. 周is information
can be added when the PDF is generated. Some PDF export
modules have a ‘Tagging’ option or an option with a similar
name. 周is enables structural information to be transferred
into a PDF. It is also possible to add structural information
later on in Adobe Acrobat Professional. Alternatively, it might
be possible to convert the file to PDF/A-1b instead.
■■MarkInfo missing: 周is message only appears when vali-
dating PDF/A-1a (and not when validating PDF/A-1b). 周e
document does not contain any information on its structure
(in the structure info directory). 周e stricter PDF/A-1a stan-
dard stipulates that a PDF file must contain structural infor-
mation. Remedy: To resolve this problem, the PDF file must be
given the relevant structural information. 周is information
can be added when the PDF is generated. Some PDF export
modules have a ‘Tagging’ option or an option with a similar
name. 周is enables structural information to be transferred
into a PDF. It is also possible to add structural information
later on in Adobe Acrobat Professional. Alternatively, it might
be possible to convert the file to PDF/A-1b instead.
■■Max. nesting level of graphic states exceeded: 周e PDF
file contains very deeply nested page objects that can cause
problems when it is printed out. Every PDF/A file must be a
basically correct PDF file. 周e file currently open violates the
restrictions of the PDF specification, which limits the degree
of nesting for page objects. It is therefore not compliant with
the PDF specification and cannot be converted to PDF/A.
Remedy: 周e problem can possibly be resolved by opening the
file in Adobe Acrobat and saving it once again using the ‘Save
As’ option. Otherwise, it might be possible to clean it up us-
ing the ‘Save Optimized As’ option.
■■Max. number of colorants for DeviceN exceeded: An
object uses too many color channels in a DeviceN object. De-
viceN is a multi-channel color space in which spot colors can
also be used, for example. DeviceN objects can be used in
PDF/A files but the number of channels is restricted to a max-
imum of 8. Remedy: It is extremely unusual for a DeviceN
color space to use more than 8 channels. Tools such as the
Acrobat Preflight module can be used to find out which com-
ponent uses the color space in question. 周e error can then be
corrected. 周e object in question must be recreated and the
PDF file must then be regenerated.
■■Metadata does not conform to XMP: 周e PDF/A stan-
dard stipulates that document information must exist in the
XMP area. 周is document has XMP metadata but it is incor-
rectly formatted. Remedy: 周e file must be either converted
to PDF/A again or the PDF document must be regenerated.
■■Metadata entry missing: No document information for
the PDF/Aentry. 周e PDF/A standard stipulates that document
information must exist in the XMP area. 周ere is no XMP
document information in this PDF file. Remedy: 周e ‘Save As’
command in Acrobat can be used to solve this problem. XMP
metadata is created during the generation of PDF/A.
■■Metadata not embedded as plain text: 周e PDF/A stan-
dard stipulates that document information must exist in the
XMP area and must not be compressed. However, the XMP
metadata in this PDF is compressed. Remedy: 周e file must
be either converted to PDF/A again or the PDF document
must be regenerated.
■■More than one encoding in symbolic TrueType font’s
cmap: A symbol font has more than one allocation table,
which means that characters cannot be uniquely identified.
周e PDF/Astandard stipulates that TrueType font that is also
a symbol font may only contain a single encoding entry. Oth-
erwise, unique allocation is impossible. Remedy: To resolve
this problem, the PDF file must be created anew.
■■Named action with a value other than standard page
navigation used: PDF files can dynamically alter their con-
tent during visualization. Actions can be contained in the
PDF file for this purpose. 周e PDF/A standard stipulates that
the visualization of a document must be guaranteed and al-
ways the same. For this reason, active content is not permit-
ted in PDF/A files. 周e only exception is elements for page
navigation. Remedy: 周is problem can be solved using the Ac-
robat PDF Optimizer or pdfaPilot.
■■NeedAppearances flag present but not set to false:
Form fields can be filled with variable content. 周ese initially
empty fields can have an entry that defines that they must be
filled with variable content (either through user input or in-
put that is determined dynamically such as the system envi-
ronment or time). Because the PDF/A standard stipulates that
the visualization of a document must always be identical
whether it is displayed on a monitor or output on a printer,
form fields in PDF/A documents must not contain this entry.
Remedy: As long as the content in question is not adversely
affected, the ‘Flatten form fields’ PDF Optimizer function
can be used to correct this error.
■■Number of PDF/A-1 OutputIntent entries > 1: 周ere are
multiple output intents for PDF/A. 周is is not compliant with
the PDF/A standard. Output intents are used to define the
colors used in a PDF in accordance with a specific output
76
PDF/A
in a Nutshell
What the Preflight error messages mean
99
procedure (for example, printing or display on a monitor).
周is uniquely defines color specifications. Consequently, only
a single PDF/A output intent may be specified for a PDF/A
file. Remedy: Acrobat 8 Preflight has a correction option that
removes all output intents from a document. 周e user has to
create a new profile and choose the option ‘Remove Output
Intent’ from the list of predefined corrections. Since the cor-
rection removes all output intents, the document must then
be converted to PDF/A again.
■■OutputConditionIdentifier missing or empty in PDF/A
OutputIntent: 周e output intent is incomplete. 周e output
condition identifier is missing. Remedy: New PDF/A conver-
sion.
■■Page description contains invalid operator: 周e PDF
file uses invalid commands for the page description. Every
PDF/A file must be a basically correct PDF file. 周e file that is
currently open uses a command in its page description that is
not defined in the PDF specification. 周is file is not a valid
PDF file. It is therefore not possible to convert it to PDF/A.
Remedy: 周e problem can possibly be resolved by opening the
file in Adobe Acrobat and saving it once again using the ‘Save
As’ option. Otherwise, it might be possible to clean it up us-
ing the ‘Save Optimized As’ option. If the problem still exists,
the PDF file must be regenerated.
■■PDF contains data after end of file marker: Every PDF
file should have an end of file marker. No further data should
follow this marker. In this PDF, there is data a晴er the end of
file marker. Remedy: 周e ‘Save As’ command in Acrobat can
be used to solve this problem.
■■PDF contains EF (embedded file) entry: 周e document
contains an entry for an embedded file. In PDF files, other
files can be embedded as an attachment in a similar manner
as with an e-mail. 周e corresponding program is required to
view these files (for example, Microso晴 Word if a Word file is
embedded). Because the PDF/A standard stipulates that it
must be possible to visualize all components of a PDF file
without the aid of other so晴ware, file attachments are not
permitted in PDF/A files. Remedy: 周e Acrobat PDF Opti-
mizer contains an option called ‘Discard file attachments’ in
the ‘Discard Objects’ area. 周is option corrects the error.
■■PDF/A Destination profile version 4 or newer: 周e file
has an output intent, but the ICC profile used is not compat-
ible with PDF/A. Because the PDF/A standard stipulates that
colors must appear the same (as far as is technically possible)
regardless of the output device, either a PDF/A document
must only contain device-neutral colors or the color proper-
ties of the output device must be defined using an output in-
tent profile. If a document contains DeviceRGB or DeviceC-
MYK colors, an output intent of the same type must therefore
exist. Remedy: New PDF/A conversion.
■■PDF/A entry missing: No PDF/A entry in the document
information. A PDF/A file must have a corresponding entry
in its document information. 周is entry can also be displayed
with Adobe Acrobat. To display it, the user must choose
‘Properties’ from the ‘File’ menu in Adobe Acrobat and then
click the ‘Additional Metadata...’ button. 周e entry appears in
the ‘Advanced’ section under http://www.aiim.org/pdfa/ns/
id/. 周ere must be a ‘pdfaid:part: 1’ entry for the PDF/A ver-
sion (only version 1 at present) and a ‘pdfaid:conformance:’
entry for the conformity level (PDF/A-1a or PDF/A-1b). 周e
conformity level must be ‘A’ or ‘B’. PDF/A-1a files are always
compliant with PDF/A-1b. Remedy: 周e file can be converted
to PDF/A again.
■■PDF/A OutputIntent has no destination profile: Because
the PDF/A standard stipulates that colors must appear the
same (as far as is technically possible) regardless of the output
device, either a PDF/A document must only contain device-
neutral colors or the color properties of the output device
must be defined using an output intent profile. If a document
contains DeviceRGB or DeviceCMYK colors, an output in-
tent of the same type must therefore exist, along with its des-
tination profile. Remedy: Preflight contains a correction op-
tion that converts the alternate visualization to CMYK
(SWOP). 周is correction must be duplicated and an RGB
color space such as sRGB must be used as the target. 周e cor-
rection can then be assigned to a profile. 周e alternate visu-
alization of the spot color can then be modified. pdfaPilot
can also carry out this task.
■■Producer mismatch between Document Info and XMP
metadata: 周e PDF ‘Producer’ entry in the XMP document
information deviates from the corresponding entry in the
document properties. 周e PDF/A standard stipulates that
document information must exist in the XMP area. If this
data is also contained in the document properties, it must be
identical to the entries in the XMP area. Remedy: New PDF/A
conversion.
■■Prohibited annotation type: A PDF can contain differ-
ent types of comment. Some of these comment types are in-
tended for multimedia content: Sound and movie comment
types. 周ese types of comment cannot be reproduced by
printers. 周e FileAttachment comment type allows files in
other formats to be embedded into a PDF. Only specialized
visualization systems are able to render these file attach-
ments. 周ese types of comment are not permitted in PDF/A
files as they cannot be visualized on all output devices. In ad-
What the Preflight error messages mean
PDF/A
in a Nutshell
77
99
dition, all types of comment that were not specified in PDF
1.4 (from Adobe Acrobat 5 onwards) are not permitted in
PDF/A since PDF/A is based on PDF 1.4. Remedy: 周e Acro-
bat PDF Optimizer provides an option for removing file at-
tachments in the ‘Discard User Data’ area.
■■RGB used but PDF/A OutputIntent not RGB: Device-
dependent color (DeviceRGB) is used but no RGB output in-
tent exists. Because the PDF/A standard stipulates that colors
must appear the same (as far as is technically possible) re-
gardless of the output device, either a PDF/A document must
only contain device-neutral colors or the color properties of
the output device must be defined using an output intent pro-
file. If a document contains DeviceRGB or DeviceCMYK col-
ors, an output intent of the same type must therefore exist.
Remedy: New PDF/A conversion.
■■RGB used for alt. color but PDF/A OutputIntent not RGB:
A spot color has been defined in DeviceRGB but the output
intent is not defined for RGB. Because the PDF/A standard
stipulates that colors must appear the same (as far as is techni-
cally possible) regardless of the output device, either a PDF/A
document must only contain device-neutral colors or the color
properties of the output device must be defined using an out-
put intent profile. If a document contains DeviceRGB or De-
viceCMYK colors, an output intent of the same type must
therefore exist. Remedy: New PDF/A conversion.
■■Scaling factor used: Page contains a zoom factor or
downsizing factor. 周is PDF defines a change of image scale.
周is particular characteristic was first introduced with Ado-
be PDF 1.6 (as of Acrobat 7). 周e PDF/A standard only per-
mits objects that are compatible with PDF 1.4. A change of
image scale is therefore not permitted in PDF/A files. Reme-
dy: 周is problem can be corrected using the Acrobat PDF Op-
timizer by selecting PDF 1.5 compatibility (Acrobat 6).
■■SMask entry present with a value other than None: A
partially transparent mask is used in this PDF file. Masks hide
background objects. 周ey can however be set to ‘transparent’
in PDF files so that objects positioned behind them still remain
partially visible. You can set a percentage value on a scale of 0%
to 100% to define the extent to which the background of a
‘transparent’ object should be visible. 周e color values of the
foreground mask and background object must be offset against
one another for the reproduction of such constructions when
displaying files on a monitor or printing them out. However,
this method of blending is not clearly defined. 周e PDF/A stan-
dard stipulates that all features used in a PDF file must be dis-
played in a single unique way on a monitor or in a printout.
Because this cannot be ensured in the case of transparent ob-
jects and their backgrounds, transparency is not permitted in
PDF/A files. Remedy: Adobe Acrobat Professional (Version 6,
7, or 8) includes a flattener module that can be used to remove
transparencies.
■■Stream object contains F entry: To be visualized in its
entirety, this PDF requires additional files. Because the PDF/A
standard stipulates that a PDF must be complete and must
not require any other information for its visualization, this
PDF cannot be converted to PDF/A. Remedy: It is unusual for
external files to be required for the visualization process. In
order to trace the cause, a file that produces this error must
be checked – with Adobe Preflight, for example – to see which
objects are to blame.
■■Stream object contains FDecodeParams entry: External
files are required for the visualization of the file in question
(FDecodeParams entry). To be visualized in its entirety, this
PDF requires additional files. Because the PDF/A standard stip-
ulates that a PDF must be complete and must not require any
other information for its visualization, this PDF cannot be con-
verted to PDF/A. Remedy: It is unusual for external files to be
required for the visualization process. In order to trace the cause,
a file that produces this error must be checked – with Adobe
Preflight, for example – to see which objects are to blame.
■■Stream object contains FFilter entry: External files are
required for the visualization of the file in question (FFilter
entry). To be visualized in its entirety, this PDF requires ad-
ditional files. Because the PDF/A standard stipulates that a
PDF must be complete and must not require any other infor-
mation for its visualization, this PDF cannot be converted to
PDF/A. Remedy: It is unusual for external files to be required
for the visualization process. In order to trace the cause, a file
that produces this error must be checked – with Adobe Pre-
flight, for example – to see which objects are to blame.
■■Stream size is above 2 GB: A data stream in this file is too
large (the maximum permitted size is 2 GB). Extremely large
files may lead to rendering problems when the files in ques-
tion are printed out or displayed on a monitor. 周e maximum
file size and also the size of internal data objects in PDF/A
files is therefore limited to 2 GB. Remedy: No repair possible.
It may be possible to recreate the PDF file with a more effec-
tive compression type.
■■Subject mismatch between Document Info and XMP
metadata: 周e ‘Subject’ entry in the XMP document informa-
tion deviates from the corresponding entry in the document
properties. 周e PDF/A standard stipulates that document in-
formation must exist in the XMP area. If this data is also con-
tained in the document properties, it must be identical to the
entries in the XMP area. Remedy: New PDF/A conversion.
78
PDF/A
in a Nutshell
What the Preflight error messages mean
99
■■Text cannot be mapped to Unicode: 周is message only
appears when validating PDF/A-1a (and not when validating
PDF/A-1b). 周is PDF file contains characters that could not
be allocated to a Unicode ID since the relevant information is
not available in the PDF file. Remedy: In order to resolve this
problem, the PDF file must be created anew, using a different
font. Alternatively, it might be possible to convert the file to
PDF/A-1b instead.
■■Title mismatch between Document Info and XMP
metadata: 周e ‘Title’ entry in the XMP document informa-
tion deviates from the corresponding entry in the document
properties. 周e PDF/A standard stipulates that document in-
formation must exist in the XMP area. If this data is also con-
tained in the document properties, it must be identical to the
entries in the XMP area. Remedy: 周is information can be
opened using the ‘File’ menu and changed in the general
Document Properties dialog.
■■TR2 entry used with value other than Default: Underly-
ing gradation curve. 周e color values of a page object (text,
images, graphics, and so on) can be changed with the aid of
gradation curves (or ‘transfer curves’). On the basis of a
‘transfer curve’, a new value is determined for every color
value when a document is displayed on a monitor or printed
out. 周is value is then displayed or printed in place of the
‘original value’. Because not all devices can handle transfer
curves, they are not permitted in PDF/A files. Remedy: 周e
Preflight ‘Apply transfer curves’ function corrects this error.
■■Transparency used: Objects in this PDF file are defined
as ‘transparent’. 周e PDF/A standard stipulates that all fea-
tures used in a PDF file must be displayed in a single unique
way on a monitor or in a printout. Because this cannot be
ensured in the case of transparent objects and their back-
grounds, transparency is not permitted in PDF/A files. Rem-
edy: Adobe Acrobat Professional (Version 6, 7, or 8) includes
a flattener module that can be used to remove transparen-
cies.
■■Type 2 CID font: CIDToGIDMap invalid or missing: Not
all characters (glyphs) can be allocated to this font (CI-
DToGIDMap is missing or incorrect). A font in this PDF does
not have a complete allocation table for allocating character
codes to character representations in the font. In PDF/A files,
the reliable allocation of codes to character representations
must be ensured. Remedy: In order to resolve this problem,
the PDF file must be created anew, using a different font.
■■Uses NChannel color: An object in this file uses the
NChannel color space, which is not allowed in PDF/A. 周e
document defines colors in the ‘NChannel’ color space, in-
troduced with Acrobat 7 (PDF 1.6). NChannel is an extension
of the DeviceN color space, permitted since PDF 1.3. Both
color spaces allow the specification of color values in multi-
channel color spaces in which spot colors, for example, may
also be used. 周e PDF/A standard does not support objects
that were not permitted in the PDF 1.4 specification that was
published by Adobe with Acrobat 5. Remedy: Use the Acrobat
PDF Optimizer to save the PDF file as a PDF 1.4 version.
■■Uses OpenType font: OpenType fonts may not be used in
PDF/A files. 周ere are various common font formats (Post-
Script Type1, Type3 or TrueType). 周ey can be embedded in
all PDF versions. As of PDF 1.5 (Acrobat 6), OpenType for-
mat fonts can also be embedded. 周is font format is used by
one of the fonts embedded in this PDF file. 周e PDF/A stan-
dard only permits the use of objects that are compatible with
PDF 1.4. Fonts in OpenType format must therefore not be
used or embedded. Remedy: In order to resolve this problem,
the PDF file must be created anew, using a different font.
■■Width information for glyphs incomplete: Width infor-
mation is missing for some characters in a font used in this
document. 周e letters and other characters used in PDF texts
require ‘fonts’ that determine their exact appearance when
visualized. 周e characters used in the text are then depicted
and arranged in accordance with the representation stored in
the font. 周e precise position of each character depends upon
the tracking of the previous character. 周e PDF/A standard
stipulates that width information must be available for every
single character used in a document. Remedy: To resolve this
problem, the PDF file must be created anew.
■■Width information for glyphs is inconsistent: Deviating
specifications exist for character width. 周e letters and other
characters used in PDF texts require ‘fonts’ that determine
their exact appearance when visualized. 周e characters used
in the text are then depicted and arranged in accordance with
the representation stored in the font. 周e precise position of
each character depends upon the width of the preceding
symbol. 周e width specification for any one character is de-
fined both in the font that is embedded in the PDF and in the
PDF itself. 周e PDF/A standard stipulates that the width
specifications in the embedded font and in the PDF file must
be identical. Remedy: To resolve this problem, the PDF file
must be created anew.
■■Wrong encoding for non-symbolic TrueType font: 周is
font does not use standard character to symbol allocation
(MacRoman or WinAnsi). 周is PDF can therefore not be
converted to PDF/A. Remedy: In order to resolve this prob-
lem, the PDF file must be created anew, using a different
font.
What the Preflight error messages mean
PDF/A
in a Nutshell
79
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