Re: CMYK settings
Re: CMYK settings
- Subject: Re: CMYK settings
- From: Dan Reid <email@hidden>
- Date: Thu, 29 May 2003 12:42:41 -0700
on 5/29/03 5:49 AM, Roger Breton at email@hidden wrote:
>
> How can I decipher such data as dot gain, GCR, black
>
> generation, total ink limit from a custom CMYK profile
>
> or one that comes with Photoshop such as SWOP Coated
>
> V2?
>
> Is there an application out there that does that and
>
> would also help me edit the data?
>
>
>
> Thanks,
>
> Faro
>
>
One thing you could do -- I have done that many times to 'reverse engineer'
>
some CMYK profiles -- is to create a Lab neutral ramp, from 0 to 100, in
>
steps of 10. Convert this Lab ramp to the CMYK profile you want to study
>
using whatever conversion settings you like. Then, using some graph paper,
>
label the vertical axis 'screen percentages' (from 1% to 400%) and the
>
'horizontal' axis Lightness (from L=0 to L=100). Find some Prismacolor
>
crayons. A cyan, a magenta, a yellow and a black ought to do. Now, back in
>
Photoshop on your converted ramp, select the color picker tool (5x5 area)
>
and position it to read what was L=100 and observe the converted CMYK
>
values. Ideally, these should all be zeroes. Next, read what was L=10 and do
>
the same thing. Plot the read CMYK % on your graph using your Prismacolors.
>
Repeat the same process for all your patches in your ramp until you've
>
reached L=0. If you link all the color dots on your graph with the
>
corresponding Prismacolor crayons (use cyan for all cyan dots, etc.) you'll
>
end up with four curves who correspond to the process separation. And that's
>
where the learning begins for you. For one thing, you'll discovered that
>
black never starts at 5, 10, or 20% but somewhere further towards 45 or 50%.
>
>
What I suggest do is you download and study all the TR-001 profiles from
>
Chromix. You'll get a better idea of all these separation parameters after
>
you study those.
>
>
Regards,
>
>
Roger Breton
>
Laval, Canada
>
email@hidden
>
Wow that sounds fun! Definitely a good learning approach.
If you are less inclined to plotting, and you want to part with some money,
you can use Xrite's new ColorShop X based upon Chris Halford's ICC Tools
ProfileView product. Very cool stuff.
<
http://www.xrite.com/Products/Product.asp?Show=Description&id=505>
--
Dan B. Reid
RENAISSANCE PHOTOGRAPHIC IMAGING
Color Management Products & Training for Print, Internet, & Motion Graphics
http://www.rpimaging.com | Toll Free: (866) RGB-CMYK
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