LWF rookie has just bought new gamma-corrected monitor

[Metin_7]

Hi guys,

I've just bought a Samsung SyncMaster 226BW monitor, because my old monitor died this weekend. The Samsung has a great dynamic screen, which is gamma-corrected. So I am more or less forced to dive into Linear WorkFlow now. With my previous monitor a Max gamma value of 1.7 did the job.

I've read a number of threads about LWF and there's a whole lot of confusing theoretical babble about 0.4545454545, sRGB, EXR etc. I just want to render in the Max VFB, 8-bit TIFF output, no post-production.

I read somewhere that in V-Ray 1.5 final the right procedure is as follows:

1: Max prefs gamma to 2.2, bitmap input gamma also to 2.2 (furthermore check the 'affect ...' options).
2: V-Ray color correction linear, gamma value 2.2 (equivalent to the old value of 0.454).

But if I do this, then the render becomes too light and washed-out, as if there's a double gamma correction.

So what I've got now is:

1: Max prefs gamma to 2.2, bitmap input gamma also to 2.2 (furthermore checked the 'affect ...' options).
2: V-Ray color correction Reinhard with 0.5 burn value and gamma value left at 1.0.

I guess I should leave the V-Ray gamma to 1.0 because my monitor is already natively gamma-corrected and the Max prefs gamma is already correcting the output to 2.2.

But please correct me if I'm doing anything wrong. At this moment, the difference between full black (RGB 0,0,0) and a very dark grey value (e.g. RGB 8,8,8 ) is too drastic, causing black areas to appear here and there. Here's an example I rendered yesterday evening:



As you can see on the back of the woman character, there's a relatively large difference between black and dark grey.

Thanks very much in advance for your feedback!

All the best,

Metin

[bob-cat]

There are heaps and heaps of posts about this but simply:

1. Max - Enable gamma and the input bitmap gamma @ 2.2, check the affect color and Mat editor.

2. Set Vray Color mapping to linear and enable the Vray frame buffer.

3. To render either:

a. Set the Vray color mapping gamma to 1, and check the srgb button in the VFB, save as exr (floating point).

b. Set the Vray color mapping gamma to 2.2, and uncheck the srgb button in the VFB, save as jpg. (non-floating point).

[Metin_7]

Thanks very much, I guess I'm going to say goodbye to the Max VFB then. Hello V-Ray VFB!

[bob-cat]

No, this was just the easiest way to explain it.

I always use the VFB while doing tests to view locally, and swap to the MFB for network rendering.

Just remember if you want to save as floating point (.exr, .vrimg) set gamma @ 1, if you want to save as non-floating point set gamma to 2.2.

[DanielBrew]

Hi Metin,

I think most of what you're doing is right.

I also have a Samsung flat screen and I use first setup you tried. I believe this is correct if you use the VRay VFB as I do but as you realised it is double correcting for the max VFB.

I guess you are finding it necessary to use a Reinhard burn value of 0.5 because you are using the same lighting setup on this scene are you would have done before you switched to LWF. I found that I could reduce light intensity by 25% to 50% when I switched to LWF.

I'm not sure how to fix the black of the woman's dress but it might have something to do with that you are gamma correcting your bitmaps for materials as they go into Max but you are not correcting your material colours. You could try using a VRaycolor map for materials that use colour chips or procedurals to fix this.

I hope some of this helps,

Dan

[Metin_7]

Ok, tried your steps, but the result is exactly the same as doing this:

1: Max prefs gamma to 2.2, bitmap input gamma also to 2.2 (furthermore check the 'affect ...' options).

2: V-Ray color correction linear, gamma value 1.0.

3: Render with Max VFB.

So I guess to get the render result I want I have to experiment with the different color mapping methods (Reinhard with a 0.5 value is the best so far, to my liking).

[Metin_7]

Hi Dan,

Thank you too for your feedback. I posted my previous message right after you posted yours, so I didn't read it yet.

I'm going to experiment now. At least I know that I'm not forgetting something important, but it's just a matter of tweaking to your personal liking.

Cheerio,

Metin

[bob-cat]

In the VFB you need to check the sRGB button at the bottom of the VFB to see the corrected image.

This will be different to the Max frame buffer.

[sea2stars]

You may also want to check to see which version of the monitor you have.

"The Samsung 226BW, there are three versions!"

[CGdiggs]

If your are working with a gamma 1.0 (linear) monitor you do not need to set the MAX Gamma to 2.2 when working with a LWF.

Use option III from the following thread:

http://chaosgroup.com/forums/vbullet...ad.php?t=33917

Cheers,

Diego