CS2 Assigning highlight with eyedropper

No replies to this on the PS Mac forum, hopefully someone here can help. . .

I have a CMYK image. In the levels dialogue I have the White Point Eye Dropper set to 5,3,3,0. When I click on a highlight area in the image that has a value of 0,0,0,0 it gets set to 6,6,6,0, rather than 5,3,3,0 which the tool is set to. The same thing happens if I apply auto levels. Can anyone explain why different values are being applied and how to rectify it?

Could this be resolved by something like trashing preferences?

thanks,
Jim

The eyedroppers have never been extremely accurate, especially at either end of the tonal range. The best way to set your white and black points is manually using Curves, not Levels. My results were closer using the white dropper, with a 5,3,3 target ending up 4,2,2 in one instance and something a little farther away in another. I think it depends on how close the image is already to your goal. In any event, it still is not the best tool for the job. Linocolor, when I used to use that did have a feature that would accurately set the highlight and still leave speculars at paper white.

Thanks for the reply/info Peter.

FWIW: I just found that the results, applying the eyedropper, are more accurate when applied to an RGB image, before converting to CMYK. This is what I usually do (process images in RGB), but I received some CMYK files with clipped highlights.

Generally putting a visible dot into an existing specular highlight, even one that has been created by clipping, will only serve to limit the already limited dynamic range of the printing process. If there is no printable detail in the area, you're almost always better off leaving it paper white and concentrating on the parts of the image with good detail.