Converting PDF to CMYK (with identify recognizing CMYK)

Question

I am having much trouble to get ImageMagick\'s identify to, well, identify a PDF as CMYK.

Essentially, let\'s say I\'m building this file, test.t

Answer 1

I have an unrelated problem but I am also struggling with CMYK PDFs currently.

I wrote this little script here (it's called pdf2pdfx):

#!/bin/bash

gs \
-dPDFX \
-dBATCH \
-dNOPAUSE \
-dNOOUTERSAVE \
-sDEVICE=pdfwrite \
-sColorConversionStrategy=CMYK \
-dProcessColorModel=/DeviceCMYK \
-dPDFSETTINGS=/prepress \
-sOutputFile="${1%%.pdf}_X-3.pdf" \
PDFX_def.ps \
"$1"

and my PDFX_def.ps contains the following (I removed the ICC profile and defined FOGRA39, this should be OK):

%!
% $Id$
% This is a sample prefix file for creating a PDF/X-3 document.
% Feel free to modify entries marked with "Customize".

% This assumes an ICC profile to reside in the file (ISO Coated sb.icc),
% unless the user modifies the corresponding line below.

systemdict /ProcessColorModel known {
  systemdict /ProcessColorModel get dup /DeviceGray ne exch /DeviceCMYK ne and
} {
  true
} ifelse
{ (ERROR: ProcessColorModel must be /DeviceGray or DeviceCMYK.)=
  /ProcessColorModel cvx /rangecheck signalerror
} if

% Define entries to the document Info dictionary :

% /ICCProfile (/usr/share/color/icc/ISOcoated_v2_300_eci.icc) def  % Customize or remove.

[ /GTS_PDFXVersion (PDF/X-3:2002) % Must be so (the standard requires).
  /Title (Title)                  % Customize.
  /Trapped /False                 % Must be so (Ghostscript doesn't provide other).
  /DOCINFO pdfmark

% Define an ICC profile :

currentdict /ICCProfile known {
  [/_objdef {icc_PDFX} /type /stream /OBJ pdfmark
  [{icc_PDFX} <> /PUT pdfmark
  [{icc_PDFX} ICCProfile (r) file /PUT pdfmark
} if

% Define the output intent dictionary :

[/_objdef {OutputIntent_PDFX} /type /dict /OBJ pdfmark
[{OutputIntent_PDFX} <<
  /Type /OutputIntent              % Must be so (the standard requires).
  /S /GTS_PDFX                     % Must be so (the standard requires).
  /OutputCondition (Commercial and specialty printing) % Customize
  /Info (none)                     % Customize
  /OutputConditionIdentifier (FOGRA39)      % Customize
  /RegistryName (http://www.color.org)   % Must be so (the standard requires).
  currentdict /ICCProfile known {
    /DestOutputProfile {icc_PDFX}  % Must be so (see above).
  } if
>> /PUT pdfmark
[{Catalog} <> /PUT pdfmark

Identify then correctly reports CMYK colorspace. Before:

tbart@blackknight ~/orpheus/werbung/action $ identify -verbose action_schulungsvideo_v3_print.pdf
Image: action_schulungsvideo_v3_print.pdf
  Format: PDF (Portable Document Format)
  Class: DirectClass
  Geometry: 612x859+0+0
  Resolution: 72x72
  Print size: 8.5x11.9306
  Units: Undefined
  Type: TrueColor
  Endianess: Undefined
  Colorspace: RGB
  Depth: 16/8-bit
  Channel depth:
    red: 8-bit
    green: 8-bit
    blue: 8-bit
  Channel statistics:
    Red:
      min: 0 (0)
      max: 65535 (1)
      mean: 53873.6 (0.822058)
      standard deviation: 19276.7 (0.294144)
      kurtosis: 1.854
      skewness: -1.82565
    Green:
      min: 0 (0)
      max: 65535 (1)
      mean: 55385.6 (0.84513)
      standard deviation: 19274.6 (0.294112)
      kurtosis: 2.09868
      skewness: -1.91651
    Blue:
      min: 0 (0)
      max: 65535 (1)
      mean: 51020 (0.778516)
      standard deviation: 20077.7 (0.306367)
      kurtosis: 0.860627
      skewness: -1.52344
  Image statistics:
    Overall:
      min: 0 (0)
      max: 65535 (1)
      mean: 53426.4 (0.815235)
      standard deviation: 19546.7 (0.298263)
      kurtosis: 1.59453
      skewness: -1.75701
  Rendering intent: Undefined
  Interlace: None
  Background color: white
  Border color: rgb(223,223,223)
  Matte color: grey74
  Transparent color: black
  Compose: Over
  Page geometry: 612x859+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Undefined
  Orientation: Undefined
  Properties:
    date:create: 2011-09-14T15:38:57+02:00
    date:modify: 2011-09-14T15:38:57+02:00
    pdf:HiResBoundingBox: 612.283x858.898+0+0
    pdf:Version: PDF-1.5 
    signature: 210bfc9cf90e3b9505385f8b2267da1665b5c2de28bb5223311afba01718bbeb
  Artifacts:
    verbose: true
  Tainted: False
  Filesize: 1.577MBB
  Number pixels: 526KB
  Pixels per second: 52.57MB
  User time: 0.020u
  Elapsed time: 0:01.009
  Version: ImageMagick 6.6.5-6 2011-04-08 Q16 http://www.imagemagick.org

after:

tbart@blackknight ~/orpheus/werbung/action $ pdf2pdfx action_schulungsvideo_v3_print.pdf
GPL Ghostscript 9.04 (2011-08-05)
Copyright (C) 2011 Artifex Software, Inc.  All rights reserved.
This software comes with NO WARRANTY: see the file PUBLIC for details.
Processing pages 1 through 1.
Page 1


tbart@blackknight ~/orpheus/werbung/action $ identify -verbose action_schulungsvideo_v3_print_X-3.pdf 
Image: action_schulungsvideo_v3_print_X-3.pdf
  Format: PDF (Portable Document Format)
  Class: DirectClass
  Geometry: 612x859+0+0
  Resolution: 72x72
  Print size: 8.5x11.9306
  Units: Undefined
  Type: ColorSeparation
  Base type: ColorSeparation
  Endianess: Undefined
  Colorspace: CMYK
  Depth: 16/8-bit
  Channel depth:
    cyan: 8-bit
    magenta: 8-bit
    yellow: 8-bit
    black: 8-bit
  Channel statistics:
    Cyan:
      min: 0 (0)
      max: 65535 (1)
      mean: 8331.78 (0.127135)
      standard deviation: 14902.2 (0.227392)
      kurtosis: 1.62171
      skewness: 1.7799
    Magenta:
      min: 0 (0)
      max: 62194 (0.94902)
      mean: 6739.34 (0.102836)
      standard deviation: 14517.5 (0.221523)
      kurtosis: 2.08183
      skewness: 1.93276
    Yellow:
      min: 0 (0)
      max: 65535 (1)
      mean: 13310.1 (0.203098)
      standard deviation: 17022.5 (0.259746)
      kurtosis: 0.991135
      skewness: 1.45216
    Black:
      min: 0 (0)
      max: 56540 (0.862745)
      mean: 7117.47 (0.108606)
      standard deviation: 16803.7 (0.256408)
      kurtosis: 3.02752
      skewness: 2.16554
  Image statistics:
    Overall:
      min: 0 (0)
      max: 65535 (1)
      mean: 8874.66 (0.135419)
      standard deviation: 15850.6 (0.241864)
      kurtosis: 2.17614
      skewness: 1.88139
  Total ink density: 292%
  Rendering intent: Undefined
  Interlace: None
  Background color: white
  Border color: cmyk(223,223,223,0)
  Matte color: grey74
  Transparent color: black
  Compose: Over
  Page geometry: 612x859+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Undefined
  Orientation: Undefined
  Properties:
    date:create: 2011-09-14T15:39:30+02:00
    date:modify: 2011-09-14T15:39:30+02:00
    pdf:HiResBoundingBox: 612.28x858.9+0+0
    pdf:Version: PDF-1.3 
    signature: 0416db7487ea147b974ece5748bc4284e82bfc3fb7cd07a4de050421ba112076
  Artifacts:
    verbose: true
  Tainted: False
  Filesize: 2.103MBB
  Number pixels: 526KB
  Pixels per second: 5.25708PB
  User time: 0.000u
  Elapsed time: 0:01.000
  Version: ImageMagick 6.6.5-6 2011-04-08 Q16 http://www.imagemagick.org

This is on 64bit Gentoo with gs 9.04 Maybe that helps?

Source PDF stems from inkscape pdf export, colors were restricted to those covered in ECI ISO coated v2. I use this as a workaround for the lacking CMYK export of inkscape and the lacking prepress-ready PDF/X output...