[cgbeige]

I'm unable to get a correct colour space from 32-bit renders. If I assign an sRGB profile to 32-bit renders in Nuke (which works fine with Mental Ray's renderer), the color is way off:



Is there some trick to getting this to work?

[Mihai]

Looks like the exposure changes, not the colors?

[cgbeige]

hard to say since the red isn't just darker, it's clamped badly

[cgbeige]

another bug: other channels only render as PNGs, not the specified output format.

[juan]

We are checking your issue right now. Are you able to get the correct color space in other depths (8/16..)? What 32 bits format are you using? (If you are using tiff32 please try with EXR and let us know)

Thanks,

Juan

[juan]

another bug: other channels only render as PNGs, not the specified output format.

Please open the preferences panel in Maxwell/Menu/File/Preferences and go to the Channels section. The format used by channels is not affected by the format used by the render output, because usually you always want your channels in the same format. In example you'd never save the velocity channel in a low depth format, if you did it this channel would be unusable. Therefore we decided to add this option at preference level instead of at project level, this behavior could be changed if most of the people asked for it, although we've already asked a lot of people and it seems the current way to do it is fine.

Thanks,

Juan

[cgbeige]

it's the same regardless of whether I use EXR or TIFF.

[cgbeige]

Can I request that EXR be added as a format in the Maya plug-in? thx

oops - wrong thread.

[juan]

Besides to this, I forgot to mention that now MXI files embed render channels as well, so if you want to change the channel format after the render is done, you just need to open the MXI file, select the channel you want, and save the image. Since the image is generated using the high precision MXI buffer, there is not loss in this step. (You can also create a simple script for doing it in in a group of files and convert the whole sequence to another format in a few clicks)

Thanks,

Juan

[cgbeige]

ok - thanks. unfortunately, I can't embed alphas in 16/32-bit EXR or TIFF files though. Is that on the list of bugs to fix? Is the forum the best way to submit bugs?

[jfrancis]

I'm not sure if this is relevant. Maybe you already know, and maybe it does not apply, but...

When I open in Photoshop CS4 a Maxwell 32-bit image that was rendered with gamma 2.2 and burn 0.8 the color is way off until I ask for an 'Exposure' adjustment layer and set the gamma slider to 2.2 and the exposure slider to -0.2

Maybe something analogous would help you?

gamma 2.2 in Nuke, and brightness of .80 --- and if the gamma makes it worse, try 1/gamma = 1/2.2 = 0.45

[juan]

ok - thanks. unfortunately, I can't embed alphas in 16/32-bit EXR or TIFF files though. Is that on the list of bugs to fix? Is the forum the best way to submit bugs?

Embeding alpha is working but for tif32 maybe you will need to make a workaround, as I've explained it here
http://www.maxwellrender.com/forum/view ... 77#p308977
Please let us know if you need more help here.

Thanks,

Juan

[Mihai]

I tried rendering a 16b tiff with embedded alpha from Studio and it works. Could you please confirm? Seems it's plugin related then and I'll move it to plugin bugs. But please try to keep one issue per thread.

[cgbeige]

ya, I guess I should have thought about degamma-ing. I just tried it in Nuke and it seems that 1.8 was the right setting, not 2.2 and then I had to use a Color Correct offset of -0.02. This got me very close:

http://www.3eige.com/cgtalk/mr2fixednuke.jpg

So that seems like it. It's still an issue with Maya though with 32-bit files since the returned tonemapping is off.

[jfrancis]

Now I thought I had it figured out, but my colors are still off.

Photoshop is asking for a color profile. Profoto is a little too peach-colored, and srgb and adobe1998 seem too green-yellow.

Is there a correct procedure for 1.7? Or should I just use Photoshop color correction tools as necessary?