Crazy Homeless Guy

What is your gamma output set to in the Max preference dialog? ...also, are you using color workspace are you using in PhotoShop, and if your monitor is calibrated, what is it calibrated to?

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Travis Schmiesing
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danb4026

I enabled Gamma/LUT Correction & Load Enable State with Max file.
Gamma set to 1.8
Check "effect Color Selectors"
Check "Affect Material Editor"

Bitmaps input = 1.8
Bitmaps output = 1.8

The only thing not checked is "Autodesk View LUT"

I set my gamma output to 1.8 in max's prefs. Whe I open the file as an exr in PS, it is a bit washed out, but as a JPEG it looks fine, matches my rendrering great. I am using Working RGB in PS.

Crazy Homeless Guy

You have your output gamma set to 1.8, which is means that any rendered file you are saving has this gamma value saved with it. When saving to EXR formats, you typically save out the files with a gamma of 1.0. When you open your EXR file in PhotoShop, it will display it with the gamma of the color space you are working in. Hence you are applying a gamma correction of 1.8 when you save out of 3dsmax, and you are applying a gamma correction again when you open the file in PhotoShop.

Bassically you are double gamma correcting you EXR's. If you set 3dmax's output gamma to 1.0, and save a EXR, then your EXR should open fine in PhotoShop.

But you jpeg will appear to dark.

To illustrate this, open one of your EXR's that appear to bright in PhotoShop. Now use the exposure control to adjust the gamma to 0.555. It should now look identical to you rendering as it was in 3dsmax. The 0.555 is the inverse of one of the gamma's. It is basically removing one of the gamma's that you applied to the image.

The equation.....

1 divided by 1.8 equals 0.555

or

1/1.8 = 0.555

While this corrects your image, it should not be the way you work. If you are going to leave the output gamma in your Max pref settings to 1.8, then you need to be saving out as a TIF, TGA, Jpeg, or other standard format.

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SandmanNinja

I'm gonna have to re-read this a few times.

I just rendered a scene with frame buffer set to 16-bit and saved it to a JPG and it's too dark in photoshop and web browsers.

I set the frame buffer to 32-bit, saved it as a HDR, opened it in photoshop - and it looks the same as in 3DS. I adjust the image to 8-bit, save it as a JPG with no gamma correction, and the final jpg looks fine.

Am I doing it right?

(edit: I need coffee)

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Mike.

THAt is a revelation for me. i never cared about all this gamma thing.
Just spent 2 hours reading, and i must admit i've been doing things the wrong way for some years now!!

thanks all for sharing your knowaledge.

SandmanNinja

Oh - I'm starting to see the light.
Let me get this straight.

The gamma correction depends on the file format that I'm saving to?

So:
If I save to a JPG, TIF, BMP, any-8-bit-format, set OUTPUT GAMMA to 1.8
If I save to a HDR, EXR, or any 32-bit format, set OUTPUT GAMMA to 1.0
Hope I can wrap my head around this.

[time passes - experiments performed]

Okay - I think I finally get it.

I click Customise -> Preferences -> Gamme/Lut -> set gamma input and output both to 1.0

I click Render -> Renderer tab -> Frame Buffer set to 32-bit

I did a very basic render with a HDRI and a primitive.

If I set the OUTPUT GAMMA to 1.0 and save it as a HDR, then it looks just like it does in 3DS.
JUST CHANGING THE FILETYPE TO JPG yields a very dark image - wrong gamma.

If I set the OUTPUT GAMMA to 1.8 and save it as a JPG, then it looks just like it does in 3DS.

So, I need to adjust my OUTPUT GAMMA according to what my file type is going to be.

Attached Images

comparison.jpg (173.7 KB, 55 views)

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AJLynn

Yes, you've got it. And I still say Max's gamma handling is really messed up.

shaneis

Completely agree. Maya's just as bad. Much better to render to a 32-bit format and apply gamma correction and tone-mapping in post.

On a side-note, have been experimenting with Cinepaint for the last week. Excellent with exr! Currently linux-only, but the developers are working on a Windows port. Stay-tuned or install linux...choice is yours

Crazy Homeless Guy

Now I need to do some experimenting to see if I should be working with a gamma of 1.8 instead of 2.2. I have been using 2.2 for the last couple of years, but most in this thread like a 1.8, and Rodrigo Neoscape was pushing 1.8 at the DMVC.

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Travis Schmiesing
www.hok.com

Timothy Saunders

Ninja, Thanks a load for the summary of your understanding of Travis's explanation. It simply wasn't clicking for me, He's just smarter than me, or his hair is just cooler than mine (it is by the way).

I still have problems with hdr and exr renders, even set at 1.0. 1- they appear too dark in the frame buffer, 2- they still open with the washed out look of 2.2 in photoshop.

At least 8 and 16 bit images are opening great in photoshop--and for that, I am ready and able to have babies for both Ninja and Travis. I'm sure I'll see you in SanFran next year if that's where they decide to hold DMVC09.

Anyway, I suggest rendering tifs (either 8 or 16-bit) as you can open them as Camera RAW images for extra control.

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