Re: Scum dots? when converting from RGB To CMYK
Re: Scum dots? when converting from RGB To CMYK
- Subject: Re: Scum dots? when converting from RGB To CMYK
- From: "Bruce J. Lindbloom" <email@hidden>
- Date: Wed, 28 Nov 2001 09:28:02 -0600
Pat Hagan wrote:
>
...when I print a CMYK Tiff from either Photoshop, or Pagemaker, that has been
>
converted from RGB to CMYK,I get faint cyan dots all over the image.
My guess would be that the CMYK printer profile has an even number of grid
points in the Lab-to-CMYK LUTs. You can check this by opening your printer
profile with Apple's ColorSync Profile Inspector, select the B2A1 tag and
look at the top of the window where it says "N grid points in each CLUT
dimension." If N is an even number, then that is probably your problem.
When an even number is used, then there is no sample in the table for pure
white, and instead, white must be interpolated from neighboring samples,
which may lead to "scum dots."
If this is the case, you should complain to the vendor of the software that
created the profile. B2A tags should always have an odd number of samples,
IMO.
--
Bruce J. Lindbloom
www.brucelindbloom.com