Re: Getting Dot Gain From Profile
Re: Getting Dot Gain From Profile
- Subject: Re: Getting Dot Gain From Profile
- From: Graeme Gill <email@hidden>
- Date: Wed, 14 Apr 2004 12:27:37 +1000
- Organization: Color Technology Solutions
Don Hutcheson wrote:
If anyone has a good method for calculating status T CMY densities (or any
status, for that matter) from Lab, please let me know. Due to the absence of
original spectral data, any method will be flawed, but there has to be a way
of obtaining a reasonable approximation.
You don't have to convert to status T. Status T is just a way of
separating out the density of each colorant, possibly in the
presence of other colorants, with a high signal to noise ratio.
If you can get the colorant on its own, then even a wide band
reflectance measurement (like L* or Y) is sufficient. You get
a colorants L* or Y value on its own, by feeding 0 into the
the profile for the other colorants.
So, taking some random CMYK profile:
icclu -ff -ia -px cmyk.icm
0.000000 0.000000 0.000000 0.000000 [CMYK] -> Lut -> 0.882552 0.911102 0.779203 [XYZ]
0.500000 0.000000 0.000000 0.000000 [CMYK] -> Lut -> 0.334138 0.404473 0.637367 [XYZ]
1.000000 0.000000 0.000000 0.000000 [CMYK] -> Lut -> 0.148493 0.219604 0.541810 [XYZ]
Dot Gain = 100*[.91-.40]/[.91-.22]-50 = 23.9% for Cyan
Graeme Gill.
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