Re: [APML] RGB -> CMYK

[Larry McManus <lmcmanus@clearpointadv.com>]

Matt

Excellent job.

Larry McManus


on 3/7/03 3:35 PM, Matt BenDaniel at matt@starmatt.com wrote:

> 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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