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Convert / create TIFF images using ImageMagick tools without losing black options

I need to create a TIFF for printing. Special black tones are usually used to improve visual perception. This is cmyk (40%, 40%, 40%, 100%) in my case.

No matter what I do when combining the two images (layout), the convert tool converts my cmyk (40%, 40%, 40%, 100%) into cmyk (0,0,0,255).

Example:

  • background.tif is an 8-bit CMYK TIF with LZW compression filled with cmyk (40%, 40%, 40%, 100%).
  • textlayer.tif is an 8-bit CMYK TIF with LZW compression with a transparent background and yellow text.

I'm calling:

/usr/bin/convert -colorspace cmyk \
-compress lzw \
-depth '8' \
-endian msb \
-density 360x360 \
-units PixelsPerInch \
-profile ISOcoated_v2_300_eci.icc \
background.tif textlayer.tif -composite print.tif

When I now check the resulting "print.tif", the most used color is:

% identify -verbose print.tif | grep -A 2 Histogram
  Histogram:
   1674545: (  0,  0,  0,255) #000000FF cmyk(0,0,0,255)
       164: (  0,  0,  1,254) #000001FE cmyk(0,0,1,254)

But this is not a black background:

%identify -verbose background.tif  | grep -A 2 Histogram
   Histogram:
    1817895: (102,102,102,255) #666666FF cmyk(102,102,102,255)
   Rendering intent: Perceptual

What happened? How can i do this?

+3
1

.

400x300 , :

  • 40c40m40y100k
  • 100- .

TZF LZW. ISOcoated_v2_300_eci.icc, CYMK convert:

$ convert -colorspace cmyk \
-compress lzw \
-depth '8' \
-endian msb \
-density 360x360 \
-units PixelsPerInch \
-profile ~/Library/ColorSync/Profiles/USWebCoatedSWOP.icc \
rich-black-bg.tif yellow-type-tx.tif \
-composite composite-lzw-profile.tif

identify , egrep, ( 100 ). , identify , . , :

$ identify -verbose rich-black-bg.tif yellow-type-tx.tif \
composite-lzw-profile.tif | egrep 'Image\:.*\.tif$|Histogram|^\s+\d{3,}\:'

Image: rich-black-bg.tif
  Histogram:
    120000: (102,102,102,255) #666666FF cmyk(102,102,102,255)
Image: yellow-type-tx.tif
  Histogram:
    114603: (  0,  0,  0,  0,  0) #0000000000 cmyka(0,0,0,0,0)
      4584: (  0,  0,255,  0,255) #0000FF00 cmyka(0,0,255,0,1)
       150: (  0,  0,255,  0, 34) #0000FF0022 cmyka(0,0,255,0,0.133333)
       107: (  0,  0,255,  0,153) #0000FF0099 cmyka(0,0,255,0,0.6)
       100: (  0,  0,255,  0,221) #0000FF00DD cmyka(0,0,255,0,0.866667)
Image: composite-lzw-profile.tif
  Histogram:
      4584: (  0,  0,255,  0) #0000FF00 cmyk(0,0,255,0)
       100: ( 14, 14,235, 34) #0E0EEB22 cmyk(14,14,235,34)
       107: ( 41, 41,194,102) #2929C266 cmyk(41,41,194,102)
       150: ( 88, 88,122,221) #58587ADD cmyk(88,88,122,221)
    114603: (102,102,102,255) #666666FF cmyk(102,102,102,255)

ImageMagick 6.8.9-7 Mac OS X v10.10.1.

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