linear workflow

[bottom]

Hi there,
I've just started with Octane and having quickly scanned through the manuals I can't find anything on setup for linear workflow.
In vray/mentalray/modo I would set the gamma to 2.2 and then make various other adjustments and say in vray would then use the srgb adjustment in the frame buffer to get an adjusted feedback.
Now I guess with octane you would set all the inputs to linear, set the gamma to 2.2 and then click the linear/off button this seems to give a correct looking adjusted image?
Just wanted to run this by the pros and see if this is the correct course of action?

Cheers

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[hadouken]

I'm curious about this too. Does the linear options really function for a linear workflow or does it represent something else? Also, do camera filters observe the linear workflow or should all camera filters be turned off? Do texture maps come in gamma corrected? In max I have the option of using the systems gamme, image gamma, or manual gamma per image.

[Hastule]

I too am curious about this! This sounds alot like the workflow that the person I am interning for talks alot about. He uses Maya+Vray,2.2 gamme srgb etc etc.....and gets really good quality images. In octane however, when I render the same scene,even with linear/off camera filter and 2.2 gamma my colors look WAY worse and dingy compared to the images he renders out

[matej]

I was doing some material which colors I tried to match from a reference pic. So I opened the pic in GIMP, picked the color and then pasted the HTML code into Octane. There I realized that the color in the Octane picker looks a lot more different (on the same monitor) than in GIMP. As you can see the HTML code (circled in light blue) is the same in both pickers:

So, yeah, I'm interested too how Octane treats colors and which would be the right workflow? In GIMP I have the default monitor color profile, but Octane doesn't support color profiles. Is that why there is such difference in the apparent color?

[hadouken]

Wow, that's interesting... hmm. I wonder if Octane gamma corrects the color picker or not. In max, there's an option to show gamma correction in color picker and materials. As far as I know, there's no similar option in Octane. I'm not sure how to explain the disparity.Anyone?

[matej]

@hadouken, I think you are right about gamma. If I gamma correct the color from GIMP (the one that is more dark) with 2.2 (default Octane gamma) I get the same washed out color as in Octane. And if I gamma correct the color I picked in GIMP with 1/2.2, then past it's HTML code to Octane I get the right color that matches the original reference.

The question now is; does this input gamma correction happens also with textures? If someone would clearly explain things around the color workflow with Octane, it would be great.

Also, about the original question; The tonemapper applies only to output not to input, it seems, so there's no way to change how Octane treats input?

[roeland]

The inputs of the color picker, including the HEX input are linear. So it is unfortunately not very useful for web colors (which are normally given in sRGB space). We will look at how to resolve this issue.

Image textures have an input to specify their gamma correction (it is set to 2.2 by default).

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Roeland

[matej]

Thanks for the clarification.

If we could eventually have the option to use a linear or gamma corrected picker in Octane, it would be great. For example all the graphical applications I use, have gamma corrected picker, so a color of (0.5, 0, 0) is consistent among them, except in Octane where is brighter.

[dkreset]

so I did some fiddling around with the info here .. migrating from Vray to Octane but I'm finding some weird differences. In Vray I would set the output gamma to sRGB which is 2.2 so the image gets the adjusted response like mentioned above .. but I would then set the textures on import to 0.454 which is the inverse of 2.2 to make sure my images are in linear color space so it won't get brightened by the gamma out put again and become blown out. So I tried to do the same in octane, set the gamma to 2.2 and that makes my render brighter as expected. I then went to my imported texture gamma setting and did an inverse of .454 but it ended up getting brighter? It turns darker if I do it in photoshop and works properly for Vray and Mental ray...

can anyone shed some light regarding this? If i wanted to get a linear workflow going, what would I have to do in Octane to make sure things are in the same color space so I'm not getting unexpected results?

Thanks in advance guys!

[roeland]

Most images are encoded with a gamma correction of 0.45455, and to get the data back in linear space Octane needs to do the inverse correction (with gamma = 2.2). Some programs ask the gamma value used to encode the image (the input gamma) and apply the inverse correction. Octane asks the gamma value for the correction, so you have to set it to 2.2.

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Roeland