D800e Red Oversaturation

Started Apr 15, 2013 | Discussions thread
Julian Vrieslander
Contributing MemberPosts: 919
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Gamut limiting (with example)
In reply to Tony Beach, Apr 18, 2013

Tony Beach wrote:

michaeladawson wrote:

All I do know is that you have to be very conscious of the red channel because that is the one that will tend to blow out first.

This is very infrequently true.  The green channel blows out first far more often than the red channel.

I have seen the red channel clipping first only in rare, rather pathological cases.  It can happen if the scene has intense red, orange, or yellow, and there is not enough content from other colors for the white balance algorithm to compute an appropriate solution.

The only thing you can really do is expose for the red channel and handle correction in post.

How are you evaluating exposure for the red channel?  Do you set your camera up with neutral settings such as a linear curve?  Do you use uni-WB?  If not then it is likely you are underexposing the entire file to address a problem that lies elsewhere.

Yes, you can underexpose and then correct that in post processing; or better still, you can expose properly and address the problem with oversaturated reds in the conversion of the Raw file by avoiding high saturation, possibly applying a negative exposure compensation, and watching your output gamut.

Tony's comments throughout this thread are right on the mark.  Some of the people posting comments do not seem to understand how white balance affects the scaling of the contents in the RGB channels.

Most of the time, when I am having problems with the red channel, it is because of gamut limits. The Sony sensor in my D800E can capture very saturated reds (contrary to rumors repeated here).  Consider this image, which I shot yesterday:

http://julian.marmotandweasel.com/photos/20130416_0852small.jpg

This was captured as a RAW file, and processed in ACR and PS CS6, using Adobe Standard camera profile.  I made minor tweaks to WB, shadows and highlights, but no significant changes to color.  All processing was done in the ProPhoto color space, and the JPEG was saved with ProPhoto profile.

I edited the image on a NEC PA271 wide gamut monitor. The red and yellow flowers appear as I recall them: vividly colored and three-dimensional. If you are not viewing the image on a calibrated wide gamut display and using a color managed application, the flowers may look flat, pasty, and dull.  When I want to put shots like this on web, I have to convert to sRGB and the results can be heart-breaking. The difference can be huge. Sure, I can desaturate the clipped colors to recover some detail in the L channel, but it's just not the same image.

On a possibly related issue: some people claim that ACR and the Adobe Standard profile produces oversaturated colors.  When I compare with raw conversions in ViewNX 2 and Nikon's SD profile, the colors look muted and undersaturated.  Maybe this is matter of personal taste.  Or perhaps Nikon's software is tuned for sRGB monitors.

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