POV-Ray : Newsgroups : povray.beta-test : Beta 37 changes to file gamma? Server Time
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From: clipka
Subject: Re: Beta 37 changes to file gamma?
Date: 5 May 2010 07:51:11
Message: <4be15baf$1@news.povray.org>
Am 03.05.2010 20:25, schrieb JJ:

> I have the same problems with PovRay 3.7 beta 37.
> Previous beta version was OK for me : 3.7 beta 36. But for installation of beta
> 37 it was need to uninstall beta 36... Now all pictures are white...
> I tried with this ini seetings:
> ====================================================================
> ; Persistence Of Vision raytracer version 3.5 sample file.
> File_Gamma = 0.980
> Display_Gamma = 0.980
> Antialias=On
> Sampling_Method=1
> Antialias_Threshold=0.1
> Antialias_Depth=4
> Input_File_Name=name.pov
> Output_Alpha=off
> Output_File_Type=N   ;; S= bmp, T=uncompressed tga&   N png output
> +w800
> +h600
>
> ;+w3200
> ;+h2400
> Cyclic_Animation=off
> Pause_when_Done=on
> ===================================================================

Are you sure these are the same settings that you used with beta.36?

To be frank, I can't imagine you used PNG output when working with 
beta.36 - because with PNG files, it doesn't matter what encoding gamma 
(derived from File_Gamma) is used: They will only seem to match the 
render preview if you set the proper Display_Gamma for your system 
(provided the image viewer does a proper job).


Anyway, a beta.37a is just about to be released that will restore 
beta.36 gamma behavior.


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From: JJ
Subject: Re: Beta 37 changes to file gamma?
Date: 5 May 2010 08:50:00
Message: <web.4be168fc90dc9ef6cdadb0b0@news.povray.org>
clipka <ano### [at] anonymousorg> wrote:

> > ====================================================================
> > ; Persistence Of Vision raytracer version 3.5 sample file.
> > File_Gamma = 0.980
> > Display_Gamma = 0.980
> > Antialias=On
> > Sampling_Method=1
> > Antialias_Threshold=0.1
> > Antialias_Depth=4
> > Input_File_Name=name.pov
> > Output_Alpha=off
> > Output_File_Type=N   ;; S= bmp, T=uncompressed tga&   N png output
> > +w800
> > +h600
> >
> > ;+w3200
> > ;+h2400
> > Cyclic_Animation=off
> > Pause_when_Done=on
> > ===================================================================
>
> Are you sure these are the same settings that you used with beta.36?
>
> To be frank, I can't imagine you used PNG output when working with
> beta.36 - because with PNG files, it doesn't matter what encoding gamma
> (derived from File_Gamma) is used: They will only seem to match the
> render preview if you set the proper Display_Gamma for your system
> (provided the image viewer does a proper job).
>
>
> Anyway, a beta.37a is just about to be released that will restore
> beta.36 gamma behavior.

Hello Clipka and Alain,
If two povman have the same problem, may be they are a problem somewhere in the
beta 37?
I use this ini file:

> > File_Gamma = 0.980
> > Display_Gamma = 0.980
> > Antialias=On
> > Sampling_Method=1
> > Antialias_Threshold=0.1
> > Antialias_Depth=4
> > Input_File_Name=name.pov
> > Output_Alpha=off
> > Output_File_Type=N   ;; S= bmp, T=uncompressed tga&   N png output
> > +w800
> > +h600
> >
> > ;+w3200
> > ;+h2400
> > Cyclic_Animation=off
> > Pause_when_Done=on

 With file gamma AND (so both) Display gamma values 0.98, 1.0, 2.0 and 2.2,  the
picture in the povray window and the picture in the file is not the same for
povray 3.7 beta 37 but it was OK with the previous version. My input files are
all the same, but with beta 37 the gamma is not the same. It's to much time ago
that I don't use v3.6. But finally, may be I will return back to v 3.6 because
the time need for rendering picture is the same with v3.7 beta 37 so why to use
full charge of the CPU for the same result and time consuming.

- So how to obtain the same gamma settings in the povray render windows and file
and which file format you recommand for povray 3.7 beta 37 windows XP, Vista and
7.
- If it is possible to find the previous version somewhere?

many thanks for your advices,

best regards,


JJ


Post a reply to this message

From: clipka
Subject: Re: Beta 37 changes to file gamma?
Date: 5 May 2010 10:05:39
Message: <4be17b33$1@news.povray.org>
Am 05.05.2010 14:47, schrieb JJ:
> clipka<ano### [at] anonymousorg>  wrote:
>
>> Are you sure these are the same settings that you used with beta.36?
>>
>> To be frank, I can't imagine you used PNG output when working with
>> beta.36 - because with PNG files, it doesn't matter what encoding gamma
>> (derived from File_Gamma) is used: They will only seem to match the
>> render preview if you set the proper Display_Gamma for your system
>> (provided the image viewer does a proper job).
>>
>>
>> Anyway, a beta.37a is just about to be released that will restore
>> beta.36 gamma behavior.
>
> Hello Clipka and Alain,
> If two povman have the same problem, may be they are a problem somewhere in the
> beta 37?

Believe me, one of the primary principles I go by when assessing alleged 
software errors is that the software /is/ guilty unless evidence 
/strongly/ indicates otherwise. So typically I'd try to reproduce the 
error scenario as faithfully as possible, and see if the error does 
occur or not. If it doesn't, next assumption is that I /misunderstood/ 
the error scenario, so I start toying around within different 
interpretations of the description. If that still doesn't produce the 
reported error, I go by the assumption that the error scenario was not 
/described/ properly, so I toy around even more. Only if I run out of 
ideas what might have gone wrong with the /communication/ about the 
error (and believe me, I'm quite creative at that) - or if during the 
process I find a scenario which plausibly fits the error description but 
is definitely not a bug - do I find the software not guilty.

I did some tests here, and I did find that in the scenario you 
described, beta.36 /does/ give the very same results as you report for 
beta.37.


Also note that as of now, you are the /only/ person reporting this very 
error; Quietman's problem was obviously of different nature, as the 
proposed workaround did work for him.


So I do repeat: I cannot find anything like what you report in beta.37 
(aside from the File_Gamma=1.0 issue seen by Quietman) that hadn't been 
there in beta.36 as well.

I'm not saying you can't possibly see what you claim to be seeing - but 
I do suspect that the File_Gamma=1.0 bug in beta.37 found by Quietman 
motivated you to have a much closer look at Gamma than ever in beta.36, 
and now you're surprised about 3.7 behavior that has been there for 
quite a while already, and you just never encountered it before. To me, 
the most plausible assumption is that you never tested with PNG output 
file format in beta.36 and earlier.

>   With file gamma AND (so both) Display gamma values 0.98, 1.0, 2.0 and 2.2,  the
> picture in the povray window and the picture in the file is not the same for
> povray 3.7 beta 37 but it was OK with the previous version.

That's not what I see here:

- I /do/ see outright /broken/ behavior in beta.37 with File_Gamma=1.0. 
but not for 0.98 or 2.0 or 2.2.

- I also /do/ see gamma discrepancies between preview window and written 
file for some other combinations of File_Gamma, assumed_gamma and output 
file type, but I do see those very same effects with beta.36 as well.

So my conclusion is that yes, beta.37 does behave as you report, but 
your memory of beta.36 behavior is not as accurate as you believe.

> - So how to obtain the same gamma settings in the povray render windows and file
> and which file format you recommand for povray 3.7 beta 37 windows XP, Vista and
> 7.

I strongly recommend to:

(0) Do /not/ use assumed_gamma anymore.

(1) Set Display_Gamma to a value that does really fit your display 
subsystem - so that you see in the preview window what POV-Ray expects 
you to see.

(2) If your display subsystem gamma is significantly different from 2.2, 
make sure that your image viewing program is aware of this fact - so 
that you see in your image viewing software what that software expects 
you to see (and what POV-Ray expects you to see there).

(3) Use File_Gamma=2.2 unless you want to generate height field data 
(unless you are perfectly sure you will never want to view the images on 
any other computer or share them via internet) - so that any person 
(including you possibly) viewing the output images on any other computer 
or with any other image viewing software have the best chance of seeing 
what POV-Ray expects them to see in those images.

(4) Depending on what you intend to do with the image, use either 
OpenEXR (because it's simply the best) or PNG (because it's one of the 
two most common, and does increases the chance of being displayed 
properly on other computers) as output format, or JPEG if you don't 
intend to post-process it (because it's the other of the two most common).

(5) Design your scenes to look good with these settings right from the 
start.

For /legacy/ scenes, make sure to use the "#version 3.6;" statement (or 
whatever applies), /do/ use the "assumed_gamma" statement, and do /not/ 
use the "File_Gamma" setting. Also, do /not/ use PNG output, but rather 
BMP or some such.


> - If it is possible to find the previous version somewhere?

The POV-Ray dev team has no interest whatsoever in older betas being 
circulated freely. You may want to test the brand-new beta.37a though, 
which fixes the issue reported by Quietman; I also gave it some thorough 
testing to verify that behavior is really identical to beta.36 again 
regarding output gamma. (See http://www.povray.org/beta/)


Post a reply to this message

From: Alain
Subject: Re: Beta 37 changes to file gamma?
Date: 5 May 2010 22:08:37
Message: <4be224a5$1@news.povray.org>

> clipka<ano### [at] anonymousorg>  wrote:
>
>>> ====================================================================
>>> ; Persistence Of Vision raytracer version 3.5 sample file.
>>> File_Gamma = 0.980
>>> Display_Gamma = 0.980
>>> Antialias=On
>>> Sampling_Method=1
>>> Antialias_Threshold=0.1
>>> Antialias_Depth=4
>>> Input_File_Name=name.pov
>>> Output_Alpha=off
>>> Output_File_Type=N   ;; S= bmp, T=uncompressed tga&    N png output
>>> +w800
>>> +h600
>>>
>>> ;+w3200
>>> ;+h2400
>>> Cyclic_Animation=off
>>> Pause_when_Done=on
>>> ===================================================================
>>
>> Are you sure these are the same settings that you used with beta.36?
>>
>> To be frank, I can't imagine you used PNG output when working with
>> beta.36 - because with PNG files, it doesn't matter what encoding gamma
>> (derived from File_Gamma) is used: They will only seem to match the
>> render preview if you set the proper Display_Gamma for your system
>> (provided the image viewer does a proper job).
>>
>>
>> Anyway, a beta.37a is just about to be released that will restore
>> beta.36 gamma behavior.
>
> Hello Clipka and Alain,
> If two povman have the same problem, may be they are a problem somewhere in the
> beta 37?
> I use this ini file:
>
>>> File_Gamma = 0.980
>>> Display_Gamma = 0.980
>>> Antialias=On
>>> Sampling_Method=1
>>> Antialias_Threshold=0.1
>>> Antialias_Depth=4
>>> Input_File_Name=name.pov
>>> Output_Alpha=off
>>> Output_File_Type=N   ;; S= bmp, T=uncompressed tga&    N png output
>>> +w800
>>> +h600
>>>
>>> ;+w3200
>>> ;+h2400
>>> Cyclic_Animation=off
>>> Pause_when_Done=on
>
>   With file gamma AND (so both) Display gamma values 0.98, 1.0, 2.0 and 2.2,  the
> picture in the povray window and the picture in the file is not the same for
> povray 3.7 beta 37 but it was OK with the previous version. My input files are
> all the same, but with beta 37 the gamma is not the same. It's to much time ago
> that I don't use v3.6. But finally, may be I will return back to v 3.6 because
> the time need for rendering picture is the same with v3.7 beta 37 so why to use
> full charge of the CPU for the same result and time consuming.
>
> - So how to obtain the same gamma settings in the povray render windows and file
> and which file format you recommand for povray 3.7 beta 37 windows XP, Vista and
> 7.
> - If it is possible to find the previous version somewhere?
>
> many thanks for your advices,
>
> best regards,
>
>
> JJ
>
>

My ini file DON'T contain ether File_Gamma nor Display_gamma and my 
renders show and display correctly.

Maybe it's a problem that occurs only when you explicitely set those 
parameters...



Alain


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From: Chris Cason
Subject: Re: Beta 37 changes to file gamma?
Date: 6 May 2010 01:56:11
Message: <4be259fb@news.povray.org>
On 29/04/2010 18:56, Thomas de Groot wrote:
> OK. Anyway, the choice was taken out of hands as beta 36 crashes when going 
> automatically to the update site. I produced a mini-dump file, should I send 
> it somewhere? Have others the same experience?

I'd like to get the mini-dump please - can you email it?

-- Chris


Post a reply to this message

From: Thomas de Groot
Subject: Re: Beta 37 changes to file gamma?
Date: 6 May 2010 03:40:51
Message: <4be27283$1@news.povray.org>
"Chris Cason" <del### [at] deletethistoopovrayorg> schreef in 
bericht news:4be259fb@news.povray.org...
> On 29/04/2010 18:56, Thomas de Groot wrote:
>> OK. Anyway, the choice was taken out of hands as beta 36 crashes when 
>> going
>> automatically to the update site. I produced a mini-dump file, should I 
>> send
>> it somewhere? Have others the same experience?
>
> I'd like to get the mini-dump please - can you email it?
>

OK. I send an e-mail with the mini-dump file attached, to the address 
indicated in the licence page. Subject name of mail will be "mini-dump of 
crash version 3.7"

Thomas


Post a reply to this message

From: Chris Cason
Subject: Re: Beta 37 changes to file gamma?
Date: 6 May 2010 05:05:44
Message: <4be28668@news.povray.org>
On 6/05/2010 17:40, Thomas de Groot wrote:
> OK. I send an e-mail with the mini-dump file attached, to the address
> indicated in the licence page. Subject name of mail will be "mini-dump
> of crash version 3.7"

Got it, thanks a lot, it enabled me to find the bug.

-- Chris


Post a reply to this message

From: Thomas de Groot
Subject: Re: Beta 37 changes to file gamma?
Date: 6 May 2010 09:52:20
Message: <4be2c994$1@news.povray.org>
"Chris Cason" <del### [at] deletethistoopovrayorg> schreef in 
bericht news:4be28668@news.povray.org...
>
> Got it, thanks a lot, it enabled me to find the bug.

Glad to have been of help  :-)

Thomas


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From: clipka
Subject: Re: Beta 37 changes to file gamma?
Date: 7 May 2010 09:00:41
Message: <4be40ef9$1@news.povray.org>
Am 27.04.2010 23:39, schrieb Quietman:

> The display seems ok but the output file is lighter, even with the
> default file type (BMP).

Any feedback on beta.37a behavior in this respect? Anyone still 
experiencing gamma issues?


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From: JJ
Subject: Re: Beta 37 changes to file gamma?
Date: 11 May 2010 12:45:01
Message: <web.4be9889290dc9ef6cdadb0b0@news.povray.org>
>
> To set both to the same thing, use the same value in the ini file.
>
> Set Display_Gamma to the gamma of your system. It sets the gamma for the
> preview.
>
> Set File_Gama to that same value or 2.2
>
> Maybe you have a problem with your viewer.
>
>
> Alain

Alain,

Thanks for your advices, it seems near to be OK with beta 37a now. Just need to
adjust a little bit.

Best,

JJ


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