Render channels gamma?

Numb69 · Post by **Numb69** » 30 Aug 2012, 05:48

Im basically trying to output a couple of render channels for compositing, the thing is I think the gamma doesn't get applied to the channels. ( I did enable "Apply display gamma correction" in pass options). Render looks fine, but as soon as its finished with FG and renders the image, it gets darker...I can basically add the gamma back in PS, but just wondering how would it be possible to fix this?

Thx guys!

Kzin · Post by **Kzin** » 30 Aug 2012, 06:42

Numb69 wrote:Im basically trying to output a couple of render channels for compositing, the thing is I think the gamma doesn't get applied to the channels. ( I did enable "Apply display gamma correction" in pass options). Render looks fine, but as soon as its finished with FG and renders the image, it gets darker...I can basically add the gamma back in PS, but just wondering how would it be possible to fix this?

Thx guys!

output all at gamma 1, so no gamma pass correction and do linear comp, if this is finished, do the gamma correction. and kick ps out of your comp workflow, its a bad tool then it comes to floating point. the framebuffers should not be corrected because they are then false and you cannot recreate your main pass in comp (i know you could degamma them as a minimal solution). use proper linear workflow and do the gamma thing at the end of your comp. ;)

Numb69 · Post by **Numb69** » 30 Aug 2012, 18:04

Hey Kzin thx for your reply

Just to get this straight, I still keep Softimage in Linear with color management set to 2.2 gamma but I dont write the gamma to pass, I just output the framebuffers,composite them then gamma correct them? Its just that Im used to straight output,then adjust in Photoshop. And one more thing if i can ask, Im still learning this stuff...concerning the floating point why is PS bad,and right now Im just rendering to tiff, so that wouldn't make a difference since it doesn't contain floating point values (right).Im doing stills that why I prefer photoshop, Im used to it and I find it faster..

Thx for your help man! ;)

Kzin · Post by **Kzin** » 31 Aug 2012, 06:54

you render complete linear, output all as exr, except object masks. then load all in your comp app without to do some gamma corrections. do your comp without gamma corrections except for your view. for your view to see the right result, but dont gamma correct any of your framebuffers at that point because the compapp is also expecting linear inputs. when your comp is finished, put a gamma 2,2 node at the end and save as tga or jpg or what you need.

Numb69 · Post by **Numb69** » 04 Sep 2012, 03:13

Sounds good, thx for your help ;)

Rork · Post by **Rork** » 04 Sep 2012, 08:26

No offence, but try to read up on linear workflow and compositing.
your questions seem to come from a unfamiliarity with this.

there's some really nice stuff on the web to be found on this.
not sure on your comp app, but nuke and fusion have some nice training online, free as well as paid.

rob

Numb69 · Post by **Numb69** » 04 Sep 2012, 16:57

Good point Rob. As of linear workflow I'm already familiar with it (there's always room for more training tho). It's the compositing part that Im a noob at. Im trying to render custom passes,but Im new to this, so Im still abit struggling with it. I found some good tutorials on the web,but they're not always showing the thing that I need for my specific scene so I need to experiment.
And Nuke,well forget about that I barely touched it so I have big time training to do there, luckily there's Digital Tutors

Maximus · Post by **Maximus** » 04 Sep 2012, 19:08

What parts are darker? Are you using sun+sky system? Is the sky (background) that gets darker?

Numb69 · Post by **Numb69** » 04 Sep 2012, 19:31

Well I kinda fixed the problem.There's no sky,just studio setup with planes.
Its cuz the 2.2 gamma setup in XSI (for linear worflow) doesn't get written to custom channels I output from Arch material. It only gets written to the actual pass. But its ok now, I render it in exr format and can comp later in Nuke (Once I looks at some tutorials),or worst case render to tiff and fix everything in PS

Rork · Post by **Rork** » 05 Sep 2012, 09:00

When rendering anything for compositing, stay away from gamma correction. Passes, channels or otherwise ;-)

With linear workflow gamma equals 1. And some things regarding textures have to be taken care of:
http://kobayashystips.blogspot.nl/2009/ ... image.html
http://www.rowu-media.nl/rwmblog/using- ... -or-higher

In Nuke, gamma correction is applied automatically to the viewport, so what you see is correct(ed) images.
When your comp in Nuke is done, just render to a format that will bake in the gamma. (.exr will give you comped gamma=1 images btw)

oh... PS isn't the best way to deal with stuff like this

rob

Numb69 · Post by **Numb69** » 09 Sep 2012, 19:46

Hey Rob thanks for the links, I read those awhile ago, was actually looking for those specific articles to refresh my memory lol. The thing that got me confused is the compositing part. I didn't know that Nuke would apply the gamma correction automatically and most of all I didn't know openEXR was rendering with gamma correction too, Im still trying to figure it out properly, but everything is good. rendering to exr is much better!

Oh and I figured PS wasn't that good at compositing after failed tests...but Ill stick with it until I learn nuke ;)

Render channels gamma?

Render channels gamma?

Re: Render channels gamma?

Re: Render channels gamma?

Re: Render channels gamma?

Re: Render channels gamma?

Re: Render channels gamma?

Re: Render channels gamma?

Re: Render channels gamma?

Re: Render channels gamma?

Re: Render channels gamma?

Re: Render channels gamma?