Remove Chromaticity info in PDF->TIFF

[sbleon]

Hi! I'm converting one-page PDFs to TIFF files, and the tool that consumes the TIFFs is *very* picky about its input. The TIFF I'm creating is being rejected by this tool with the spurious error message:

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TIFF is not uncompressed 1 bit or compressed using CCITT G4. File is ignored.

I say this message is spurious because my TIFF file has "Compression: Group4".

By using "identify -verbose" on a previously-converted, working TIFF and on the broken one that I've converted, I can see that all properties are identical (excepting expected differences like the histogram data, filename, hash, etc) except that the broken one has a Chromaticity section and the working one does not. The Chromaticity section is identical to that of the input PDF file.

The only way I've been able to create a working TIFF is with GraphicConverter, and I'd much rather use the free CLI tool to the job. How can I remove the Chromaticity section from the TIFF file?

For reference, here's the command I'm using:

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convert -density 500 -units PixelsPerInch -strip Downloads/ACBYX.pdf[0] -monochrome -resize 4125x5338 -compress Group4 Downloads/ACBYX.tif

[fmw42]

Have you considered other free tools to extract the embedded image from within the PDF shell? IM cannot do that, but other tools can. See pdfimages discussed at http://www.imagemagick.org/Usage/formats/#ps.

[sbleon]

Thanks, @fmw42. The PDF actually contains mostly text, so there's no image for me to extract. I'm using ghostscript (automatically via ImageMagick) to render the text to an image.

[fmw42]

Thanks, @fmw42. The PDF actually contains mostly text, so there's no image for me to extract. I'm using ghostscript (automatically via ImageMagick) to render the text to an image.

OK. Sorry for my confusion. I do not know how to remove chromaticity information. I suspect that is not the issue, but do not know what is. Can you post an example PDF that you want to convert. I have GraphicConverter also, so assume you are on a Mac.

What version of IM are you using? Is your Ghostscript up to date?

[fmw42]

convert -density 500 -units PixelsPerInch -strip Downloads/ACBYX.pdf[0] -monochrome -resize 4125x5338 -compress Group4 Downloads/ACBYX.tif

Try putting -monochrome after -resize. Resize will interpolate values and thus the bilevel status will change to grayscale. Putting it after the resize will leave your result as bi-level.

[sbleon]

Yes! Win! Thanks, Fred!!! That did the trick! The old, crusty PDF generator I'm using now happily incorporates these TIFF files

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convert -density 500 -units PixelsPerInch ACBYX.pdf[0] -background white -alpha remove -resize 4125x5338 -monochrome -compress Group4 ACBYX.tif

(I also had to remove the alpha channel and use a white background to avoid a large black border around the image.)

[fmw42]

-monochrome is an operator not a setting. Settings typically precede the operator that needs to use them, but can often precede everything but the convert. Operators, typically need to be specified in proper order. That is they can be order dependent as is the case here.

[sbleon]

So this was working great with ImageMagick 6.9.0-10. In trying to get another person set up to do these conversions, we found that TIFFs generated using 6.9.2-10 do not work, and they include the Chromaticity section that we had successfully gotten rid of before.

`identify -verbose` output from 6.9.0

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Image: ABSYX_leon.tif
  Format: TIFF (Tagged Image File Format)
  Mime type: image/tiff
  Class: DirectClass
  Geometry: 4125x5338+0+0
  Resolution: 500x500
  Print size: 8.25x10.676
  Units: PixelsPerInch
  Type: Bilevel
  Base type: Bilevel
  Endianess: LSB
  Colorspace: Gray
  Depth: 1-bit
  Channel depth:
    gray: 1-bit
  Channel statistics:
    Pixels: 22019250
    Gray:
      min: 0 (0)
      max: 1 (1)
      mean: 0.942466 (0.942466)
      standard deviation: 0.232859 (0.232859)
      kurtosis: 12.4422
      skewness: -3.80029
      entropy: 0.535885
  Colors: 2
  Histogram:
   1266846: (  0,  0,  0) #000000 gray(0)
  20752404: (255,255,255) #FFFFFF gray(255)
  Rendering intent: Undefined
  Gamma: 0.454545
  Background color: gray(255)
  Border color: gray(223)
  Matte color: gray(189)
  Transparent color: gray(0)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 4125x5338+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Group4
  Orientation: TopLeft
  Properties:
    date:create: 2016-01-13T11:26:37-05:00
    date:modify: 2016-01-13T11:26:37-05:00
    signature: a7882a86c8a51ca825f792c1b5901c0bf336c469f479f437f75c1e60ce02d31a
    tiff:alpha: unspecified
    tiff:endian: lsb
    tiff:photometric: min-is-white
    tiff:rows-per-strip: 5338
  Artifacts:
    filename: ABSYX_leon.tif
    verbose: true
  Tainted: False
  Filesize: 209KB
  Number pixels: 22.02M
  Pixels per second: 1.04853TB
  User time: 0.000u
  Elapsed time: 0:01.000
  Version: ImageMagick 6.9.0-10 Q16 x86_64 2015-03-24 http://www.imagemagick.org

`identify -verbose` output from 6.9.2

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Image: ABSYX_leon4.tif
  Format: TIFF (Tagged Image File Format)
  Mime type: image/tiff
  Class: DirectClass
  Geometry: 4125x5338+0+0
  Resolution: 500x500
  Print size: 8.25x10.676
  Units: PixelsPerInch
  Type: Bilevel
  Base type: Bilevel
  Endianess: LSB
  Colorspace: Gray
  Depth: 1-bit
  Channel depth:
    gray: 1-bit
  Channel statistics:
    Pixels: 22019250
    Gray:
      min: 0 (0)
      max: 1 (1)
      mean: 0.942422 (0.942422)
      standard deviation: 0.232943 (0.232943)
      kurtosis: 12.4289
      skewness: -3.79854
      entropy: 0.536003
  Colors: 2
  Histogram:
   1267820: (  0,  0,  0) #000000 gray(0)
  20751430: (255,255,255) #FFFFFF gray(255)
  Rendering intent: Undefined
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
  Background color: gray(255)
  Border color: gray(223)
  Matte color: gray(189)
  Transparent color: gray(0)
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 4125x5338+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Group4
  Orientation: TopLeft
  Properties:
    date:create: 2016-01-13T11:41:58-05:00
    date:modify: 2016-01-13T11:41:58-05:00
    signature: 6d951ef821693a8f744ac91377837d4921419b49da283917571c54eded3320b0
    tiff:alpha: unspecified
    tiff:endian: lsb
    tiff:photometric: min-is-white
    tiff:rows-per-strip: 5338
  Artifacts:
    filename: ABSYX_leon4.tif
    verbose: true
  Tainted: False
  Filesize: 209KB
  Number pixels: 22.02M
  Pixels per second: 1.22329TB
  User time: 0.000u
  Elapsed time: 0:01.000
  Version: ImageMagick 6.9.2-10 Q16 x86_64 2016-01-13 http://www.imagemagick.org

We want to be able to use the newest ImageMagick, of course. Any ideas about what 6.9.2 might be doing differently than 6.9.0?

[fmw42]

check the changelog at http://www.imagemagick.org/script/changelog.php to see if there is any mention of anything related to changes in TIFF between those releases.

[sbleon]

Yeah, I should have mentioned that I checked the changelog. I saw a few TIFF-related items, but nothing that seemed obviously related to my issue.

[sbleon]

6.9.1-10 doesn't work for me either. That narrows things down a bit, but I don't see any obvious culprits in the changelog between 6.9.0-10 and 6.9.1-10.

[fmw42]

Provide your PDF and I will try to pin down the exact release where it changed. Did you try to put the strip again after reading the PDF?

[sbleon]

Fred, you're the best! You can download the PDF from http://singlebrook.com/system/resources ... /ABSYX.pdf

I tried adding `-strip` after the `ABSYX.pdf[0]`, but that did not change anything. Chromaticity still stubbornly shows up.

[fmw42]

I get the Chromaticity for 6.9.0.10!

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im69010 identify ABSYX.pdf
Image: ABSYX.pdf
  Format: PDF (Portable Document Format)
  Mime type: application/pdf
  Class: DirectClass
  Geometry: 612x792+0+0
  Resolution: 72x72
  Print size: 8.5x11
  Units: Undefined
  Type: PaletteAlpha
  Endianess: Undefined
  Colorspace: sRGB
  Depth: 16/8-bit
...
  Rendering intent: Perceptual
  Gamma: 0.454545
  Chromaticity:
    red primary: (0.64,0.33)
    green primary: (0.3,0.6)
    blue primary: (0.15,0.06)
    white point: (0.3127,0.329)
  Background color: white
  Border color: srgba(223,223,223,1)
  Matte color: grey74
  Transparent color: none
  Interlace: None
  Intensity: Undefined
  Compose: Over
  Page geometry: 612x792+0+0
  Dispose: Undefined
  Iterations: 0
  Compression: Undefined
  Orientation: Undefined
  Properties:
    date:create: 2016-01-14T15:09:55-08:00
    date:modify: 2016-01-14T15:09:55-08:00
    pdf:HiResBoundingBox: 612x792+0+0
    pdf:Version: PDF-1.4 1 0 obj << 
    signature: 8bfec2c4b9782a1c3f1d054fb729fab3199508b9d402f02d99d5f254d04e2eb4
  Artifacts:
    filename: ABSYX.pdf
    verbose: true
  Tainted: False
  Filesize: 82.9KB
  Number pixels: 485K
  Pixels per second: 242.35GB
  User time: 0.000u
  Elapsed time: 0:01.000
  Version: ImageMagick 6.9.0-10 Q16 x86_64 2016-01-14 http://www.imagemagick.org

Perhaps the difference is what version of Ghostscript you are using. On my system I have

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gs --version
9.16

Perhaps you have an older version on your system for your 6.9.0.10 but a newer one on your 6.9.1.10

[sbleon]

Fred, thanks for checking that. I also get the Chromaticity when I run identify on the PDF with 6.9.0, but I don't see Chromaticity on the converted TIFF with 6.9.0. 6.9.0 manages to remove it, whereas the later versions leave it in place.

I'm using the same version of Ghostscript in all cases (9.15).