POV-Ray : Newsgroups : povray.binaries.tutorials : Check(er) Your Gamma : Re: Check(er) Your Gamma Server Time
26 Oct 2021 22:55:24 EDT (-0400)
  Re: Check(er) Your Gamma  
From: Edouard
Date: 6 Nov 2009 04:25:01
Message: <web.4af3eaec2d58a2835b81d0ec0@news.povray.org>
Ive <"ive### [at] lilysoftorg"> wrote:
> A quick note about Photoshop and it's PNG support:
>
> I'm using Photoshop since version 4.0 and currently CS3 (still not sure
> about updating to CS4) and every version had broken PNG support in one
> way or another. Usually the gamma and sRGB chunk was ignored, some
> version did completely mess up 16 bps images and CS3 writes colorimetric
> chunks (color primaries and whitepoint) but 'forgets' to add the gamma
> chunk (and it claims when saving to PNG that this file format does not
> support any metadata - a plain lie because PNG even supports XMP, the
> way that is favored by Adobe itself for storing metadata).
> Given the long time and that PNG is a quite simple format it seems not
> that far fetched that PNG support is broken deliberately - as some
> people claim - but I fail to see the reason behind it.

Yes - it should write the gamma chunk when adding  profile. It says so in the
spec.

I think PNG has never been a "pro" format in terms of their production
customers, so Adobe hasn't given it the love. I don't think it's anything more
sinister than that.

Photoshop 4? Pah - luxury! I started using version 2.0 - it didn't even have
layers!

> clipka wrote:
> |...]
> > (BTW, to scale a gamma-encoded image without messing up the colors, I
> > can highly recommend IC. It does properly convert the image to linear
> > color space before resampling.)
>
> Thanks for the advertising ;)

When's the Mac version coming out? :-)

> -Ive

Cheers,
Edouard.


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