[Sidefx-houdini-list] OT: sRGB to linear question

John Coldrick jc at axyzfx.com
Tue Jul 8 09:42:43 EDT 2008

On Tuesday 08 July 2008 09:25, Sean Lewkiw wrote:
> A question for everyone, not exactly SESI related....  When you use an
> image downloaded from the internet as a texture, do you do a sRGB to
> linear correction before using it to render with?

	Depends on your pipeline.  Strictly speaking, yes, you should.  If every 
single point along the pipeline is all sRGB all the time, including where 
you're rendering to and you don't have a problem lighting your renders in 
sRGB, then you can simply pretend it's not there and do nothing.  However, 
increasingly there's reasons to not do this, with PBR, physically accurate 
lights, etc.  If you are even coming close to having something in your 
pipeline that's not sRGB, then you should be converting everything to the 
same space(linear).

	It took us a long time and lots of conversations with lots of people to 
figure this out.  I've decided the problem is if you've ever done any film 
work of any kind, your brain suddenly switches to a world that seems to have 
a very difficult time explaining precisely *why* this is important to people 
that have traditionally worked in video only(like for advertising).  I see a 
lot of misinformation and extremely poorly explained posts all over the net 
regarding this issue.  Most of the time, people just start pointing fingers 
at others and accuse them of having incorrectly calibrated monitors(which 
does happen of course, it's just become a catch-all explanation).



John Coldrick                  www.axyzfx.com        Axyz Animation
416-504-0425                                         477 Richmond St W
                                                     Toronto, ON Canada
jc at axyzfx.com                                        M5V 3E7
When I was born I was so surprised I didn't talk for a year and a half.
  - Gracie Allen

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