More gamma stuff and linear workflows

[gilpo]

this is to be expected, since the max frame buffer is now double corrected

Are you sure? Since he followed method 2, it doesn't appear that he's burning the gamma into the final rendering. And look at the bottom of his VFB. He doesn't have the color correct curve enabled. And since his max FB materials match his material editor, it looks to me like his max fb is the correct one.

If I'm wrong, I stand corrected (no-pun intended)

_jaro: What are your color mapping settings?

[Neilg]

The VFB looks better, so use that.


Regardless of it being a question of taste - thats correct anyway. I think

[_jaro]

to gilpo I'm using Linear Multiply, value 1 for bright and value 1 for dark

to gijs ... but when I disable gamma correction in 3ds Max, image is the same as in V-ray frame buffer.
Which one is than correct?
Vray frame buffer with no correction ( but than, what is the reason for correcting mat. editor ) or corrected Max frame buffer? And how should I proceed with tweaking my textures, to have same colours in photoshop and in render, if gamma corrected frame is correct one?

[_jaro]

The VFB looks better, so use that.

I totally agree on that ( but It may be only with king of scene ).
I'm pointing to "jujubee" ( I guess ) when he pointed to fact, that he is getting better and more realistic renders with less time ( I guess because there is no need to lighten the scene so much )

[gilpo]

_jaro:
When you use LWF, your material editor will match your final rendered output. Therefore, the max FB is correct. The Vray FB doesn't read Max's gamma setting so it doesn't display correctly. You have to tell it how to show the gamma correction. There are 2 different ways to do this. ONLY DO ONE OF THESE, NOT BOTH.

1. Burn the gamma into the final image: Set your color mapping to Gamma Correction. Set your Dark Multiplier to 1 and your bright multiplier to .454545 (this is 1/2.2, the inverse of your gamma). When you do this, your vray FB will be correct, but your Max FB will be double corrected (like Gijs said).

2. Turn on the VFB color correction: There was a site that visually told how to do this but it seems to be down. I'll try to explain it here the best I can. Open up your vray frame buffer. Click on the button on the very lower left-hand corner. When the curve editor pops up, right-click on the lower left-hand point and select 'Bezier'. Grab the point's 'handle' and drag it straight up. If you notice in the upper right corner, there will be numbers shown. Drag that handle until the numbers read [ 0.00 ; 0.64 ]. Those are from memory, someone correct me if I'm wrong. Then, right-click on the upper right-hand point and select 'reset tangents'. Now close that. You've just configured the 2.2 gamma curve. Now you have to tell vray to use it. Back in the Vray Frame Buffer, click on the button that has the tool tip 'Use colors curve correction'. It's the 2nd to last at the bottom. Now your vray FB will match your Max FB. When you save an image out of Max, make sure to tell it in the save dialog that it's gama is 2.2.

Then, just adjust your materials to look like how you want them. You'll also have to tone down your lighting to make it look good.

Hope I didn't lose you. Good luck!

[_jaro]

Then, just adjust your materials to look like how you want them. You'll also have to tone down your lighting to make it look good.

I greatly appreciate your effort with explainig the stuff.

Ono more fact. When I'm not using gamma correction I have same colour in mat. editor and in frame buffer, but not in photoshop. But I would like to have same texture colour in photoshop, mat. editor and frame buffer when using gamma correction.
... or I'm loosing basic point of all that stuff with gamma correction. I do understand all the step I need to do to have gamma corrected image, but what is the basic point to do that? Maybe I'm asking wrong questions or pointing to wrong facts, but I would really like to make the thing clear for me.

[_jaro]

Which pictures are close to "real world"? Gamma corrected or non gamma corrected?

[gilpo]

Some basic advantages to working in LWF:

Realistic color bleed: 1 red wall doesn't tint your entire room red. Better light falloff: you can actually light a room with 1 light as you would in reality. Material editor better matches final render. Overall, I think LWF looks and acts more like the real world. It does take a little more work to get exteriors looking right with it, but I think it's worth it.

There might be others but these are the ones that have impacted me.

Now, as to your photoshop question, are you talking about bitmaps? As in textures? Or are you talking about the RGB values of solid colors?

[_jaro]

I mean both. Simply when I take color in photoshop it looks washed out when using gamma correction ( whatever RGB value is ), same is with bitmap textures. Then I'm not able to see what I will get when painting a texture in photoshop, or tweaking some textures based on real world scaned sample.

... LWF mean working with no gamma, or with gamma correction?

[Gijs]

Sorry for mixing things up, I hadn't taken the time to read it all over again (Vlado's post) but indeed Gilpo you're right that the max fram buffer is in this case showing the gamma corrected result. From that standpoint the only conclusion I can take is that either your materials are too light and/or the lights are too bright.

Jaro, when you turn off the max gamma, no gamma correction will be performed on the display side, that's why VFB and Max FB will look the same.

For correct results, you should basically have checked that:
your input bitmaps have either linear gamma or are converted on the fly to linear gamma during rendering
when you use colors for materials, these should be gamma corrected as well.
your lights are way less bright than you are used to.

[_jaro]

I definitely need to do some test on that topic, to make some things clear for me.
I'll post my test results later on ( and I guess with some more questions )

[alexthg]

Vlado, what if we use BOTH CRTs and LCDs ?
we got several computers here, and one of them is LCD. All CRTs are calibrated to 2.2, and our main workflow follows your method 2. Should we calibrate the LCD to gamma 2.2, or keep it to 1.0 ? though I've tried calibrating the LCD to gamma 2.2, and it looks way too dark compared to the same image on CRT 2.2 (don't know why )

will there be any problem opening the same max file using the CRT (with gamma 2.2) and LCD (with gamma 1.0) ?
if there's too much problem with having both monitor type running, then at least i know it firsthand and keep the LCD away from any render preview job.

[Burnsyman9000]

testing

[YoyoBoy]

I'm confused. How do you have Max save the image so it looks the same in Photoshop as it does in the frame buffer?

Thanks.

[jow]

in the save roll out, tick" override default gamma" and change to 2.2