[Lcms-user] Re: jpegicc-problem

[<ma...@li...>]

Hi,

> I used the current programs jpegicc.exe and tifficc.exe (win2K) to convert two
> images in jpg and tiff-format with a lot of RGB-patches into CMYK. Both have an
> ColormatchRGB-profile embedded. The jpeg is created in Photoshop 7.0.
> The command-line is :
>
> c:> tifficc  -t0  -ocmykprinter.icm   rgb.tif   cmyk.tif
> c:> jpegicc  -t0  -ocmykprinter.icm   rgb.jpg   cmyk.jpg
>
> The result of the tiff-conversion is similar to the conversion Photoshop 7.0
> does (within delta-E=2). OK!
> The result of the jpeg-conversion is awful. It looks like everything is
> reverse. White is black, green is red, blue is yellow.
>
> What did I do wrong?

Nothing. This is a problem in the way Photoshop does store CMYK JPEG.
I was told this comes from a mistake by a junior programmer in early
versions of Photoshop. For compatibility sake Adobe has kept this
particular encoding!

There is workaround, however. You can find the patched files for
jpeglib at http://www.littlecms.com/newutils.htm#jpegicc

http://www.littlecms.com/jccolor.c
http://www.littlecms.com/jdcolor.c

The precompiled windows exe is already using these ones

http://www.littlecms.com/jpegicc.exe

Hope this helps
Martí Maria
The little cms project
http://www.littlecms.com
ma...@li...



----- Original Message -----
From: "Goossen Rijnders" <go...@kn...>
To: <in...@li...>
Sent: Friday, September 27, 2002 5:43 PM
Subject: jpegicc-problem


> Hi,
>
> I used the current programs jpegicc.exe and tifficc.exe (win2K) to convert two
> images in jpg and tiff-format with a lot of RGB-patches into CMYK. Both have an
> ColormatchRGB-profile embedded. The jpeg is created in Photoshop 7.0.
> The command-line is :
>
> c:> tifficc  -t0  -ocmykprinter.icm   rgb.tif   cmyk.tif
> c:> jpegicc  -t0  -ocmykprinter.icm   rgb.jpg   cmyk.jpg
>
> The result of the tiff-conversion is similar to the conversion Photoshop 7.0
> does (within delta-E=2). OK!
> The result of the jpeg-conversion is awful. It looks like everything is
> reverse. White is black, green is red, blue is yellow.
>
> What did I do wrong?
> Please help. The results of the tiff-conversion are that good! I would like to
> see the same with pjg-images.
>
> Kind regards,
>
> Goossen Rijnders
>
>