POV-Ray : Newsgroups : povray.binaries.images : assumed_gamma makes a lemon out of U and my orange Server Time
8 Aug 2024 06:12:42 EDT (-0400)
  assumed_gamma makes a lemon out of U and my orange (Message 21 to 28 of 28)  
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From: Patrick Elliott
Subject: Re: assumed_gamma makes a lemon out of U and my orange
Date: 15 Nov 2005 21:04:44
Message: <MPG.1de44179a6dd9d45989e5c@news.povray.org>
In article <437a37a8$1@news.povray.org>, spa### [at] spamcom says...
> > Note of doom 1: chances are, the source image will probably be
> > converted from a PNG to a JPEG by a news server or blog site.
> > Doing that will either adjust it for a 2.2 display or drop the
> > gamma altogether, leaving it suitable only for the creator's
> > display.  To test this, I have attached a POV render of the
> > following scene.  The image gamma is an obscene 30, which has
> > caused all the 128/255 colour values to be elevated to 249/255.
> > When viewed in a gamma-aware viewer, the "outside" three squares
> > are much darker than the inside three, and the bottom right
> > quadrant is more orange than yellow.
> 
> Rather amusingly, Outlook Express displays it as intended, and PaintShopPro 
> screws it up :-)
> 
Was noticing that myself, at least about PSP. Figured maybe its just that 
I am using 6.0, and later ones work right. Spent an hour trying to figure 
out how, or even 'if', you could get it to work right. :(

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}


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From: Thomas de Groot
Subject: Re: assumed_gamma makes a lemon out of U and my orange
Date: 16 Nov 2005 03:29:33
Message: <437aeded@news.povray.org>
"Patrick Elliott" <sha### [at] hotmailcom> schreef in bericht
news:MPG.1de44179a6dd9d45989e5c@news.povray.org...
> > Rather amusingly, Outlook Express displays it as intended, and
PaintShopPro
> > screws it up :-)
> >
> Was noticing that myself, at least about PSP. Figured maybe its just that
> I am using 6.0, and later ones work right. Spent an hour trying to figure
> out how, or even 'if', you could get it to work right. :(
>

I am sure you looked at the monitor gamma in PSP...
I use PSP8, have its monitor gamma set at 1.00, and images are identical to
originals.
I use a flat screen, so there may be differences...

Thomas


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From: Patrick Elliott
Subject: Re: assumed_gamma makes a lemon out of U and my orange
Date: 16 Nov 2005 22:26:53
Message: <MPG.1de5a60161c9cd49989e63@news.povray.org>
In article <437aeded@news.povray.org>, t.d### [at] internlnet says...
> 
> "Patrick Elliott" <sha### [at] hotmailcom> schreef in bericht
> news:MPG.1de44179a6dd9d45989e5c@news.povray.org...
> > > Rather amusingly, Outlook Express displays it as intended, and
> PaintShopPro
> > > screws it up :-)
> > >
> > Was noticing that myself, at least about PSP. Figured maybe its just that
> > I am using 6.0, and later ones work right. Spent an hour trying to figure
> > out how, or even 'if', you could get it to work right. :(
> >
> 
> I am sure you looked at the monitor gamma in PSP...
> I use PSP8, have its monitor gamma set at 1.00, and images are identical to
> originals.
> I use a flat screen, so there may be differences...
> 
> Thomas
> 
Well. I have 6, I can adjust the gamma some place in it (its at 1.0), but 
it won't color correct when showing the image. Did you try it with the 
example image Ard gave? Opera with that one produces colors of #B80000, 
#00B800, #0000B8 for the dark squares, with #FF000, #00FF00 and #0000FF 
for the smaller squares, but it screws up the yellow, making both 
#FFB800, instead of #B8B800 and #FFFF00. With PSP 6, all I get is the 
#FF0000, #00FF00, #0000FF and #FFFF00 colors for 'everything'. The screen 
isn't the problem, the application is simply refusing to correct the 
image, so it displays properly. The image browser doesn't show it either, 
nor does the eye dropped tool show different colors for the sections, 
even though it should, unless PSP6 was simply ignoring the Gamma in the 
file entirely. Point is, you can't know if it looks the same, unless you 
know what it is supposed to look like in the first place. If its ignoring 
the gamma information, then anything 'you' produce will look the same on 
'your' system, when the gamma information is being ignored.

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}


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From: Ambis
Subject: Re: assumed_gamma makes a lemon out of U and my orange
Date: 19 Nov 2005 06:17:50
Message: <437f09de$1@news.povray.org>
Gama here and gama there. How does this gama talk apply to Flat LCD and TFT 
screens?

Greetings
Ambis


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From: Alain
Subject: Re: assumed_gamma makes a lemon out of U and my orange
Date: 19 Nov 2005 10:47:13
Message: <437f4901$1@news.povray.org>
Ambis nous apporta ses lumieres en ce 2005-11-19 06:17:
> Gama here and gama there. How does this gama talk apply to Flat LCD and TFT 
> screens?
> 
> Greetings
> Ambis
> 
> 
ALL monitors have a specific gamma value. I can't tell you the specifics for LCD, TFT
and plasma.

-- 
Alain
-------------------------------------------------
Fundamentalism #2: If shit happens to a televangelist, it's okay.


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From: scott
Subject: Re: assumed_gamma makes a lemon out of U and my orange
Date: 21 Nov 2005 16:04:36
Message: <43823664$1@news.povray.org>
"Alain" <ele### [at] netscapenet> wrote in message
news:437f4901$1@news.povray.org
> Ambis nous apporta ses lumieres en ce 2005-11-19 06:17:
>> Gama here and gama there. How does this gama talk apply to Flat
>> LCD and TFT screens?
>>
>> Greetings
>> Ambis
>>
>>
> ALL monitors have a specific gamma value. I can't tell you the
> specifics for LCD, TFT and plasma.

Most LCDs are designed to have a gamma of exactly 2.2.  It's very easy to 
set this accurately on an LCD because it just uses a look-up table to 
convert incoming bits into a voltage to apply to the LC.


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From: Kenneth
Subject: Re: assumed_gamma makes a lemon out of U and my orange
Date: 21 Nov 2005 23:05:01
Message: <web.438297ca1f234627a7b7bf6c0@news.povray.org>
I've run some gamma tests (on both .png and .bmp file types, using different
computers and monitors), but thought it best to post over on
NEWSGROUPS:GENERAL.

Ken


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From: Thomas de Groot
Subject: Re: assumed_gamma makes a lemon out of U and my orange
Date: 22 Nov 2005 03:14:35
Message: <4382d36b$1@news.povray.org>
"Patrick Elliott" <sha### [at] hotmailcom> schreef in bericht
news:MPG.1de5a60161c9cd49989e63@news.povray.org...
> In article <437aeded@news.povray.org>, t.d### [at] internlnet says...
> >
...Point is, you can't know if it looks the same, unless you
> know what it is supposed to look like in the first place. If its ignoring
> the gamma information, then anything 'you' produce will look the same on
> 'your' system, when the gamma information is being ignored.
>

Aaargh! You are right! Forgot to use my brain!

Thomas


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