photoshop, 8-bit vs. 16-bit color, and color correction

[etherealist]

Problem:

A number of images I have created are 8-bit color RGB psd files where I have used "neon green" color at various brightness and saturation levels. Originals are 300dpi at at 11x17". When I convert to CYMK to have prints made, I loose the fine gradations of green and they are all changed to a darker green color.

Question:

Would using 16-bit color help this problem? I haven't tried it yet because it doubles the size of the image and these images are already large and unwieldy for my machine to deal with. Also, if anyone has any other color correction tips / techniques, I would greatly appreciate them because I don't know a lot about this area.

Thanks in advance,
--James

[Elwell]

No, converting to 16-bit won't make any difference. Your problem is that high saturation greens are simply out of gamut in CMYK. You're going to have to hand adjust the image to reach a printable compomise.

[Jabo]

Dito, but here's a little tip I can give you so you don't have to adjust it all manually:

Image -> Adjust -> Selective Colorcorrection (hope so, I don't have the english version). Then choose "green tones" and adjust the saturation and hue sliders. One thing that will keep you in trouble is that the texture of the area will recede as soon as you push the saturation. This happens because by adding saturation, the different pixel-values will converge and thus, the difference between the pixels will be lost. You have to decide if you want saturation or texture. Find the best compromise.