Re: gamma 1.0 and loss of detail
Re: gamma 1.0 and loss of detail
- Subject: Re: gamma 1.0 and loss of detail
- From: Todd Flashner <email@hidden>
- Date: Sat, 23 Feb 2002 02:36:16 -0500
on 2/22/02 10:39 AM, Bruce J. Lindbloom wrote:
>
DeltaE_8bit_gamma1.0.tif shows the posterization problem Carl identifies.
>
This scene is illuminated with a soft edged spotlight, which produces very
>
gentle gradations of tone (without any noise). Look at the "Dark Skin" patch
>
of the ColorChecker chart (upper left patch) and also the periphery where
>
the light falls off to nothing. You can plainly see the posterization.
>
>
Compare that to the DeltaE_8bit_gamma2.2.tif, which is exactly the same, but
>
with gamma 2.2 instead of 1.0. No posterization.
Bruce,
I don't have enough experience on this topic to have an opinion yet, but I
did take a look at your images at 100% magnification in PS. To my eye the
8-bit gamma 2.2 image may have posterized a bit less than the 8-bit gamma
1.0 image, or in slightly different locations, but I still saw plenty of it.
My interest in the topic stems from the suggestion that dark images can be
improved by assigning a lower gamma working space to them, and that doing so
is less destructive to the image than lightening to a similar extent with a
curve. If that is true it gives compelling reason in favor of entering that
space. Thus, I'm wondering if the very act of bringing an image into a gamma
1.0 space is destructive to the image, or just that editing an image in that
space is destructive?
To me it becomes a question not of whether or not a thing is damaging, but
whether it is more or less damaging than other possible manipulations to
effect the same result?
Todd Flashner
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