Different IM versions returning different colorspaces

[bhagany]

We're trying to complete a long overdue upgrade from version 6.0.7 to 6.6.0, and seeing some odd behavior from identify. As a test case, we have a PDF on a shared volume, and are running identify from one box that has 6.0.7 installed, and another with 6.6.0. With the former, identify tells us the PDF's colorspace is RGB, while the latter reports CMYK. Here's the actual output:

From 6.0.7:

Code: Select all

$ identify -verbose ugh.pdf 
Image: ugh.pdf
  Format: PDF (Portable Document Format)
  Geometry: 504x360
  Class: DirectClass
  Colorspace: RGB
  Type: TrueColor
  Depth: 8 bits
  Endianess: Undefined
  Channel depth:
    Red: 8-bits
    Green: 8-bits
    Blue: 8-bits
  Channel statistics:
    Red:
      Min: 0
      Max: 255
      Mean: 234.242
      Standard deviation: 54.4106
    Green:
      Min: 0
      Max: 255
      Mean: 239.997
      Standard deviation: 41.7056
    Blue:
      Min: 0
      Max: 255
      Mean: 234.65
      Standard deviation: 53.1038
  Colors: 6222
  Rendering-intent: Undefined
  Resolution: 72x72
  Units: Undefined
  Filesize: 532kb
  Interlace: None
  Background Color: white
  Border Color: #DFDFDF
  Matte Color: grey74
  Page geometry: 504x360+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Undefined
  Orientation: Undefined
  comment:  Image generated by GNU Ghostscript (device=pnmraw)

  signature: 72bdccefeb70e324f3c8a6f9c6a18e43791127beb968932882fb43c8824a5679
  Tainted: False
  User Time: 0.020u
  Elapsed Time: 0:01

and from 6.6.0:

Code: Select all

$ identify -verbose ugh.pdf
Image: ugh.pdf
  Format: PDF (Portable Document Format)
  Class: DirectClass
  Geometry: 504x360+0+0
  Resolution: 72x72
  Print size: 7x5
  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: 42662 (0.65098)
      mean: 2785.25 (0.0425001)
      standard deviation: 9778.02 (0.149203)
      kurtosis: 10.1671
      skewness: 3.43612
    Magenta:
      min: 0 (0)
      max: 53713 (0.819608)
      mean: 1711.15 (0.0261105)
      standard deviation: 7598.77 (0.11595)
      kurtosis: 22.5903
      skewness: 4.77369
    Yellow:
      min: 0 (0)
      max: 65021 (0.992157)
      mean: 3122 (0.0476387)
      standard deviation: 9182.73 (0.14012)
      kurtosis: 12.9187
      skewness: 3.50039
    Black:
      min: 0 (0)
      max: 65535 (1)
      mean: 2091.79 (0.0319187)
      standard deviation: 6534.91 (0.0997164)
      kurtosis: 20.5652
      skewness: 4.04507
  Image statistics:
    Overall:
      min: 0 (0)
      max: 65535 (1)
      mean: 1942.04 (0.0296336)
      standard deviation: 7567.42 (0.115471)
      kurtosis: 20.5025
      skewness: 4.45851
  Total ink density: 178%
  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: 504x360+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Undefined
  Orientation: Undefined
  Properties:
    date:create: 2010-04-09T13:41:15-05:00
    date:modify: 2010-04-09T13:41:15-05:00
    pdf:HiResBoundingBox: 504x360+0+0
    pdf:Version: PDF-1.4
    signature: f6cbe077f741f9db9557f2692db143d1bafbeb2e6c1533676eb60e3290544179
  Artifacts:
    verbose: true
  Tainted: False
  Filesize: 726KB
  Number pixels: 181K
  Pixels per second: 1.8144P
  User time: 0.010u
  Elapsed time: 0:01.000
  Version: ImageMagick 6.6.0-10 2010-04-06 Q16 http://www.imagemagick.org

Does anybody have any ideas what might be causing this?

[magick]

Older versions of ImageMagick most likely did not detect certain CMYK PDF's. You can always force RGB like this:

• convert -colorspace rgb image.pdf ...