RE: [APML] RGB -> CMYK

[Matt BenDaniel <matt@starmatt.com>]

I spent a few hours doing RGB->CMYK conversions, and here's what I discovered...

I'm waiting for the magazine to provide me some CMYK color setting specs, but in the meantime, I just used the Photoshop defaults.

(All of the images below are displayed in their original RGB format.)

The first two images I converted were:

http://starmatt.com/gallery/astro/cyg_ceph.html
http://starmatt.com/gallery/astro/sky_myles.html

At first I thought it was going to be easy, because those two images do not have a lot of saturated colors. Unfortunately the shadows were modestly desaturated by the conversion, but I was able to deal with that by curving a bit before/after conversion. Pretty easy. Next image:

http://starmatt.com/gallery/astro/pleiades.html

Larry warned me that saturated blues are tough, and he was right. This Pleiades image is pretty saturated, and many of the blues are outside of the CMYK gamut. I had to use more involved and stronger curves on it, and the resulting image still lost a bit of saturation. Well, maybe the starting image was oversaturated anyway, so I suppose the result is fine.

The last image I did was:

http://starmatt.com/gallery/astro/ic1396.html

In some ways, this one was the hardest of all. I like the way my image came out in RGB. It has a lot of textures. The CMYK conversion was failing around the edges of nebula, losing the delicate transitions there. I had to lift the shadows into the CMYK gamut, convert to CMYK, then push the shadows down again.

The experience was quite interesting. I learned a lot, but I still am not "thinking" in CMYK color space yet. That'll take some more practice.
--
Matt BenDaniel
matt@starmatt.com
http://starmatt.com

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