multi color output profiles

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yannb
Posts: 5
Joined: Thu Nov 16, 2006 2:33 pm

multi color output profiles

Post by yannb » Thu Apr 12, 2007 5:12 pm

Hello,

SInce Printfab supports CMYKRB printers like the Epson Stylus Photo R800 and R1800, is it possible to address each channel individually when printing a color test chart? I have Profilemaker Packaging at my disposal, and would like to create a CMYKRB output profile.

If this cannot be done, then what color test chart would be lead to the largest gamut: RGB or CMYK?

Regards,
Yann

zedonet
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Posts: 1800
Joined: Fri Oct 06, 2006 8:02 am

Post by zedonet » Fri Apr 13, 2007 3:54 pm

Hello,

only external profiles in RGB or CMYK format are supported, the driver has a fixed conversion CMYK => CMYKRB.

CMYK and RGB lead to the same gamut - see also our PDF manual, page 46. We recommend RGB as a higher precision can be achieved with less color patches.

neon
Posts: 11
Joined: Thu Aug 04, 2011 7:55 am

Re: multi color output profiles

Post by neon » Thu Aug 04, 2011 8:01 am

for cmyk proofing, it matters if the profile installed in PrintFab is cmyk or rgb? the output could be the same, especialy the black simulation?

zedonet
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Re: multi color output profiles

Post by zedonet » Fri Aug 05, 2011 8:44 am

The difference between the two profile types is that in CMYK profiles the profiling software (in your case Profilemaker) can define the generation of black color whereas this is fixed in RGB profiles. What do you mean with "black simulation"? If you need to reproduce dark colors with "K=0" by using only Cyan, Magenty and Yellow in the printer, this would require a device link profile which is not supported for external ICC profiles in PrintFab. However, this is possible with PrintFab profiles (integrated or created by our profiling service).

neon
Posts: 11
Joined: Thu Aug 04, 2011 7:55 am

Re: multi color output profiles

Post by neon » Fri Aug 05, 2011 1:45 pm

What i mean is if i print a magazine page with color cmyk content & black only text, in prinfab cmyk proof mode i get color where is color & K only text output. All the profiles i've made so far were cmyk because i print mostly cmyk content & color proofs simulating the printing press. But it is unclear to me if i create a custom rgb profile i will get the same result. I mean the rgb profiles are much easier to make, but are they equally versatile with cmyk source?

zedonet
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Re: multi color output profiles

Post by zedonet » Mon Aug 08, 2011 7:51 am

The color reproduction
  • CMY in document => CMY in inkjet printer
    K in document => K in inkjet printer
is currently not possible with ICC profiles, only with PrintFab profiles (PrintFab's built-in profiles or created by our profiling service).

ICC profiles define a translation from device independent color (Lab) to device color (CMYK or RGB), the black generation of the original document is not respected.
There are special "device link profiles" that specifiy a direct translation from offset printing CMYK to inkjet proof printer CMYK, however this is currently not supported by PrintFab.

So there is only a slight difference between using RGB and CMYK ICC profiles in PrintFab:
  • RGB profile: easier to create, higher color precision with the same amount of color patches
    CMYK profile: black generation can be adjusted in profiling software (however, document black generation cannot be preserved)

neon
Posts: 11
Joined: Thu Aug 04, 2011 7:55 am

Re: multi color output profiles

Post by neon » Mon Aug 08, 2011 4:25 pm

in manual it says "In “CMYK Proof” mode the black (“K”) color channel of the document is printed using black ink. Thus colors can reproduced more exactly. In “CMYK Proof (Mix Black)” mode lighter shades of gray are printed by mixing primay colors. Thus shades of gray are looking less grainy."

so if i made custom profiles, with my own equipment, basically pritfab will always print in CMYK Proof (Mix Black) mode? even if i select CMYK Proof?

zedonet
Site Admin
Posts: 1800
Joined: Fri Oct 06, 2006 8:02 am

Re: multi color output profiles

Post by zedonet » Tue Aug 09, 2011 8:36 am

Yes, with external ICC profiles switching between "CMYK Proof" and "CMYK Proof (Mix black)" mode makes no difference - C100M100Y100 and K95 will be printed with almost the same inks on the inkjet printer.

You can set your profiling software to use a maximum amount of K and minimum CMY (Profile Maker: MaxK, Black Start 0%,
Black Width 100%, Black Max 100%). However, this will reduce quality of color photos in the document.

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