[pdftex] CMYK images in pdftex.

[Hartmut Henkel]

On Fri, 20 Feb 2004, John Culleton wrote:

> SO: how does one get to a pdftex document with color photos in cmyk
> form embedded?

I had the same problem, as a print shop for flyers accepted only CMYK
JPEGs, or PDF with included CMYK JPEGs, and I couldn't find any tool for
conversion. The JPEG FAQ says:

``Adobe Photoshop and some other prepress-oriented applications will
produce four-channel CMYK JPEG files when asked to save a JPEG from CMYK
image mode. Hardly anything that's not prepress-savvy will cope with
CMYK JPEGs (or any other CMYK format for that matter)...''

Conversion seems to be possible with ImageMagick, e. g.:

$ convert image10.jpg -colorspace CMYK image10a.jpg

Check by jhead:

$ jhead -v image10.jpg

JPEG image is 640w * 480h, 3 color components, 8 bits per sample

$ jhead -v image10a.jpg

JPEG image is 640w * 480h, 4 color components, 8 bits per sample

So it works. But the downside is here:

$ ls -l image10*jpg
 203835 02-20 23:50 image10a.jpg
  54368 02-20 23:05 image10.jpg

Four times the size of the RGB image! No fun.

Regards, Hartmut