More about red channels and what happens when you convert color spaces. And why
Joel may have done his orchids
perfectly, yet I found clipped red channels in some.
This expands on my last posted image comparisons by adding histograms.
<http://www.moosemystic.net/Gallery/tech/BrowserColorSpaces/TulipH.htm>
Color space conversion were done using Perceptual intent, which is, I think,
why they all appear the same.
Apparently, none of the colors, ACR default or after pretty strong LCE and
Curves, exceeds the aRGB color space, so the
ProPhoto and aRGB histograms are identical.
But, in order to maintain the same appearance the sRGB conversions move the
channels up toward the top. As this was shot
at -2/3 EV, the ACR default version still doesn't clip. But the post version
clips a fair amount.
Soooooo ... If you convert from a larger space to sRGB as the last step, and
don't check the histogram, or if you post
in a gallery that converts aRGB to sRGB, most likely with a less sophisticated
conversion engine, it's possible to have
a clipped channel without knowing it.
I was at first disappointed that this particular image doesn't show the effects
of clipping. That it is not nearly as
heavily clipped and the orchids certainly helps. The striations and other color
variations also help it avoid that 'big
blobs of one color without detail; effect that's common in red-orange-yellow
flower images.
Perhaps it's just as well, though. We've already seen the effect on a couple of
Joel's web images. To not have it
visible here shows how tricky these shots can be. And how proper technique in
shooting and processing can avoid trouble.
As shown in my previous post, one may avoid one big pitfall by posting aRGB
JPEGs, at least for the huge majority of
viewers using current version of the big four browsers.
Unshorn Moose
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What if the Hokey Pokey *IS* what it's all about?
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