"How Camp" <hac### [at] gmailcom> wrote:

> So, according to the docs, then, POV-Ray stores the gamma value as
> 1.0/display_gamma.  It also says "PNG is the only one that has any gamma
> correction features and is therefore preferred for images that will be
> displayed on a wide variety of platforms."  Isn't this somewhat misleading?

Yes, I think you're right. I was likewise confused, for quite a while. My
own guess is, that part of the POV documentation was written when PNG was
"the next big thing" and had great promise as a cross-platform and
cross-browser image display standard. But as Warp explained, things just
didn't work out the way they should have. Too bad. But you're right--that
part of the documentation should be rewritten.
>
> I'm not complaining, I'm just making sure I understand (from a user
> perspective).  If I want my image to display as I intended it, I should use
> PNG, and blame the program (browser, etc.) if it doesn't implement PNG gamma
> support properly.  On the other hand, if I want to be sure my image is
> displayed as consistently as possible, regardless of the program used to
> view it, I should opt for some other image format, and complain quietly to
> myself that I don't get to store the gamma info as I want.

Yep!  It may not be a perfect solution, but a non-gamma-embedding file
format would probably be a better choice. I use plain 'ol JPEG, but
that's lossy, of course. BMP or PICT are good choices, but the file
sizes are large. Alas, no ideal solution!

You and Warp have explained the present PNG situation quite clearly.

BTW, since I have both a PC and a Mac  -- with their different display
gammas of 2.2 and 1.8 respectively -- and since I do my POV'ing on the PC,
I've elected to alter IT's display gamma to be "in the middle" (2.0) so
that my final POV renders will look *almost* the same when viewed on both
platforms. (I do this with a utility called Adobe Gamma.) Just a small
detail, but better than nothing!

Ken

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