[gs-devel] Colour Separation output

[Made4Print]

Hi,

Yes I am using the tiffsep device, with these parameters... (ignore c# code)

commandList.Add("tiffsep");
commandList.Add("-dBATCH");
commandList.Add("-dNOPAUSE");
commandList.Add("-sDEVICE=tiffsep");
commandList.Add("-dDOINTERPOLATE");
commandList.Add("-dTextAlphaBits=4");
commandList.Add("-dGraphicsAlphaBits=4");
commandList.Add(String.Concat("-sOutputFile=", outputFilenameTemplate));
commandList.Add(String.Concat("-r", (resolution > 0 ? resolution : 120)));
commandList.Add("-MaxSeparations=8");
commandList.Add(temporaryInputFilename);

"
If you run a simple CMYK PS file, such as examples/tiger.eps you
_should_ only see K for the 'neutral' (i.e. gray or black) areas.
"

Not sure what this means, but if I run the tiger.eps file, I get these
output files, see the attachment tiger.eps.outputs.zip

This does appear to be correct.

If you look in the file magazine.zip, running the same process gives no
output on the black (I removed the full color tiff to reduce the email size,
but have the PDF inlcuded in the zip)

With these results, 'I' am expecting a black output, and what I mentioned in
the original e-mail, but am now thinking that what if this is an RGB PDF,
would this mean the RGB would be processed at CMY, and please correct me
here if this is wrong?

I am not using the -dUseCIEColor command, I will look into that and the
CRD's...

Mark



Ray Johnston wrote:
> 
> Hi Mark,
> 
> Are you using the 'tiffsep' device ?
> 
> Please send a sample file (preferably small) that shows this
> effect.
> 
> The CMYK produced will be controlled by the CRD (Color Rendering
> dictionary) for colors that are "CIE" colors, or for ALL colors
> if you specify -dUseCIEColor.
> 
> If you run a simple CMYK PS file, such as examples/tiger.eps you
> _should_ only see K for the 'neutral' (i.e. gray or black) areas.
> 
> If you are running on Windows, you can use the the command line
> option to view separations on the screen. For this, add the option:
> 
>     -dDisplayFormat=16#a0800
> 
> then you can use "right-click" in the title bar area and uncheck the
> separations that you don't want to see. For example,
> 
>     gswin32c -dDisplayFormat=16#A0800 examples/tiger.eps
> 
> This also allows you to see the CMY as Black that you get when
> you specify -dUseCIEColor using the default CRD.
> 
> For more information on CRD's, please consult Adobe's PostScript
> Language Reference Manual:
>    http://www.adobe.com/products/postscript/pdfs/PLRM.pdf
> 
> BTW, to distribute your C# wrapper, you may want to post this on
> SourceForge ( http://sourceforge.net ).
> 
> Regards,
> Ray
> ------------------------------------------------------------------------
> 
> Made4Print wrote:
>> Hi,
>>
>> I have developed a GhostScript wrapper in C# which supports color
>> separations to output all the CMYK and named spot colour tifs. I am using
>> this to try and calculate the percentage coverage of each separation.
>>
>> If I create a PDF in Photoshop or Indesign which has a certain percentage
>> of
>> black on the page, when I process the PDF seprations I am expecting blank
>> C,
>> M, and Y. however it appears that the C, M and Y separations similar and
>> relatively high values around 50% (by looking at the color in photoshop)
>>
>> Am I missing something here.
>>
>> If anyone wants the wrapper, I am happy to give this out to anyone who
>> asks,
>> please see email details at this address: 
>> http://redmanscave.blogspot.com/
>> http://redmanscave.blogspot.com/ 
>>
>> Any help will be appreciated.
>>
>> Thanks
>>
>> Mark Redman
>>
>>   
> 
> 
> _______________________________________________
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> 
> 
http://www.nabble.com/file/p14731165/tiger.eps.outputs.zip
tiger.eps.outputs.zip  http://www.nabble.com/file/p14731165/Magazine.zip
Magazine.zip 
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