Loss of colors with Adobe 7.4 RC RAF development

Started Feb 27, 2013 | Discussions thread
Imagefoundry
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Re: Loss of colors with Adobe 7.4 RC RAF development
In reply to baobob, Feb 27, 2013

What you are seeing, most likely, is the result of over-processing of chroma channels. I invite you to do the following experiment:

1. download a dpreview standard test shot both for X-trans and some decent bayer-pattern based camera, let's say D7000.

2. process both in C1, ACR 7.3 and ACR 7.4. Make sure to process to a wide gamut color space, such as say ProPhoto, and keep output to 16bit.

3. open all these files in Photoshop and convert then to LAB color mode.

4. Go to Channels pallete and review luminance and both chroma channels. Observe the differences.

Why is this relevant? Because most raw processors look at the color and luminance data in a manner similar to LAB mode, and so you can better understand what is going on.

You would probably notice that in bayer pattern images the A and B channels match the luminance L channel pretty closely (every time the color information does not match the luminance information you see effects such as color smearing, color halos, loss of saturation in small brightly colored objects and so on).

Now have a look at the chroma channels of xtrans output. You'll see that chroma channels of xtrans look strikingly different from chroma channels of bayer output. This is not an accident, xtrans design seem to be favoring luminance detail over chroma detail. One would think that Fuji weighted pros and cons of this approach very carefully before plunging ahead, and by all measures most people seem to agree - witness the high marks for Xpro1/xe1 image quality all over the internet.

Once you had a chance to compare chroma output from different raw processors, you would probably come to your own conclusions re: which one is better for your needs, but ACR 7.4 without a doubt applies some pretty heavy-handed blurring to chroma detail. Ironically, OOC jpegs from XPro1/XE1 exhibit same artifacts (to a smaller degree though) and most people don't seem to mind. So I think it's solid step forward for Adobe.

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