Re: U.S. Sheetfed vs. U.S. SWOP
Re: U.S. Sheetfed vs. U.S. SWOP
- Subject: Re: U.S. Sheetfed vs. U.S. SWOP
- From: Steve Upton <email@hidden>
- Date: Thu, 3 May 2007 09:50:24 -0700
At 1:25 PM +1000 5/3/07, Graeme Gill wrote:
>Steve Upton wrote:
>>4. Absolute Colorimetric - CSU( not available ), CTPro(default) - you are seeing the gamut of the
>>device as described by the profile. The white point is lowered to actual paper white and the
>>black point raised to ink black..
>
>When you say "raised to ink black..", this worries me. ICC relative colorimetric
>only shifts the devices absolute black point very slightly as a side effect
>of the white point shift when it is encoded into the table. The relative
>colorimetric intent tables should not have had the black point changed
>in any other way, unlike the perceptual table, which should have had its
>black point expanded to that of the reference medium black (0.30911% reflectance).
right. indeed. I meant it raised it in relation to the perceptual and saturation intents which pull it down to 0,0,0.
<snip>
> in my book, noone
>should be looking at anything other than the absolute or relative A2B table
>when it comes to examining the gamut of the device. The contents of
>all the other tables only give an indication of how the profile creation software
>is manipulating the color.
exactly! The fact that the CSU displays the perceptual table's color - with blacks pulled down to 0,0,0 and whites pulled up to 100,0,0 - as a default with no explanation to the inexperienced user about what it is they are seeing is very misleading. (sorry, huge sentence). It's not technically incorrect but it certainly implies colors on output that simple won't be there.
Regards,
Steve
________________________________________________________________________
o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX
o email@hidden 206.985.6837
o ColorGear ColorThink ColorValet ColorSmarts ProfileCentral
________________________________________________________________________
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