Adobe Community: Message List - Simple pdf file leads to wrong output color, whats wrong?

Re: Simple pdf file leads to wrong output color, whats wrong?

forums_noreply@adobe.com — Wed, 08 Jan 2014 21:05:41 GMT

A common problem for people who see CMYK as just a colour space to use when required is that they don't have the immersion in real world colour needed to really do a good job of converting.

There is a widely held idea that "RGB" and "CMYK" are colours and there must be a simple formula for converting between them. I see this all over.

Of course to actually produce an accurate similation of CMYK inks on an RGB device we need to know what colour the R,G,B phosphors are, and what colour the C,M,Y,K inks happen to be. This information is commonly expressed as ICC profiles for RGB and CMYK, and accurate colour display is going to need

- ICC colour space conversion technology

- options for specifying the colour spaces (profiles)

- end users well enough trained to correctly select the profiles and interpret the limitations of the result

Re: Simple pdf file leads to wrong output color, whats wrong?

forums_noreply@adobe.com — Wed, 08 Jan 2014 17:24:55 GMT

Thank you for helping me!

The Problem was even more complicated.

In another test file i had a eps file included, too.

This was created with inkscape. Inkscape saved the color values as rgb.

After loading the file again with inkscape, the CMYK Values were as i expected.

This can be explained that inkscape uses the same algorithm for colorspace

transformation back- and forward.

The rectancle was created with xetex, it wrote cmyk values in the file.

After loading the file with gimp, the values from the eps file were as expected,

the others not.

I didn't expect that gimp and inkscape still can't handle cmyk!

Re: Simple pdf file leads to wrong output color, whats wrong?

forums_noreply@adobe.com — Wed, 08 Jan 2014 14:32:30 GMT

Printed how?

I opened this PDF up in Acrobat, verified that the values are what you are expecting (using the Output Preview feature) and then printed on a Postscript printer. All good!

Both Inkscape and Gimp are RGB-based applications, so that they need to convert your CMYK data to RGB, which is why it shifts in those apps. You should consider using color managed data if you want that to work properly.

Simple pdf file leads to wrong output color, whats wrong?

forums_noreply@adobe.com — Wed, 08 Jan 2014 14:20:04 GMT

Hello,

i have a simple pdf file that just draws a rectangle filled with cmyk 1.0,0.35,0,0.28,

but the problem is, that this is not the color thats printed. Inkscape and gimp show

the wrong color too.

In the pdf file the color is selected with

1 0.35 0 0.28 K 1 0.35 0 0.28 k

so i do not know whats wrong here. Can anybody help?

Here is the link to the small uncompressed pdf file

http://www.opaya.de/skoepf/test.pdf

Content:

%PDF-1.5

%äðíø

4 0 obj

/Length 133

stream

q 1 0 0 1 72 769.89 cm 0 G 0 g 0 G 0 g 0 G 0 g 1 0.35 0 0.28 K 1 0.35 0 0.28 k q 0 -95 85.04 85.04 re f Q 0 G 0 g 0 G 0 g 0 G 0 g Q

endstream

endobj

6 0 obj

/Type/ObjStm

/N 5

/First 27

/Length 357

stream

5 0 3 47 7 112 2 181 1 297 <<

/ProcSet[/PDF/Text/ImageC/ImageB/ImageI]

/Resources 5 0 R

/Type/Page

/Parent 7 0 R

/Contents[4 0 R]

/Type/Pages

/Count 1

/Kids[3 0 R]

/MediaBox[0 0 595.28 841.89]

/Creator( XeTeX output 2014.01.08:1342)

/Producer(xdvipdfmx \(0.7.8\))

/CreationDate(D:20140108141527+01'00')

/Pages 7 0 R

/Type/Catalog

endstream

endobj

8 0 obj

/Type/XRef

/Root 1 0 R

/Info 2 0 R

/Size 9

/W[1 2 2]

/Length 45

stream

^@^@^@ÿÿ^B^@^F^@^D^B^@^F^@^C^B^@^F^@^A^A^@^O^@^@^B^@^F^@^@^A^@Ç^@^@^B^@^F^@^B^A^B{^@^@

endstream

endobj

startxref

635

%%EOF