# Using CMYK/Transparent images in a PDF file

I am using PDFX / Lualatex to create a PDF/X-4 file. My problem is that the publisher is wanting the images in the file to be CMYK. Some of my images are transparent.

The problem:

• Latex only supports a limited number of image formats and does not allow for TIFF
• PNG images can have transparency, but do not support CMYK colour profiles
• JPG images do support CMYK, but cannot have transparency

So, what is my solution for including a transparent and CMYK image in a PDF file that the publisher will be able to use?

• You can convert the image to a CMYK PDF. There are a limited number of open source tools that can do this. At least try ImageMagick. Scribus might also suit you. Mar 2 '20 at 3:17
• You should seek another publisher. Every print shop must be able to correctly produce a valid PDF/X document. Since you are obviously not a color expert the conversion/separation should be done by the print shop. PDF/X-4 allows RGB content. May 2 '20 at 16:18

Your only option is to convert the images to PDF which support CMYK and transparency and can by included by LaTeX.

You can do this using ImageMagick:

1. Create a simple transparent PNG (for example only):

convert magick:logo -transparent white logo.png

2. Convert the PNG to a CMYK PDF (choose appropriate profiles for your printing environment):

convert logo.png \
-profile /usr/share/color/icc/sRGB_v4_ICC_preference_displayclass.icc \
-profile /usr/share/color/icc/ISOcoated_v2_eci.icc logo.pdf

3. Test with the following TeX file (tex_logo.tex):

\documentclass{standalone}
\usepackage[cmyk]{xcolor}
\usepackage{tikz}

\begin{document}
\begin{tikzpicture}[inner sep=0pt]
% put a small grey square behind image to show the transparency
\fill [black!20] (-1,-1) rectangle (1,1);
\node at (0,0) {\includegraphics[width=54.19mm]{logo.pdf}};
\end{tikzpicture}
\end{document}

4. Use the GhostScript tiffsep device to produce separations and check that everything looks like it should:

gs -dSAFER -dNOPAUSE -dBATCH -sOutputFile=tex_logo.tiff -sDEVICE=tiffsep \
-sCompression=lzw -r300 -dTextAlphaBits=4 -dGraphicsAlphaBits=4 \
-sDefaultRGBProfile=/usr/share/color/icc/sRGB_v4_ICC_preference_displayclass.icc \
-sDefaultCMYKProfile=/usr/share/color/icc/ISOcoated_v2_eci.icc \
-sOutputICCProfile=/usr/share/color/icc/ISOcoated_v2_eci.icc tex_logo.pdf


Here's the resulting composite output and separations:

Composite

Cyan separation

Magenta separation

Yellow separation

Black separation

• Such a nice suggestion... Mar 2 '20 at 11:42