"Dont affect colors" problem

[ARTECONI-CGI]

I'm already testing. I get much more noise from the lights but I guess this is correct.

[rivoli]

I'm glad if that helped. and yes, I'm in the rainy milano right now..
here's another one with a white-ish mat at 120. if you start from there and tune any other mat in scene accordingly, you can get quite a bit of contrast..

[ARTECONI-CGI]

London. I think I win in terms of rain.

Seriousely you gave me a great hint!

What was the white of the 1st test? 64?

Giacomo.

[rivoli]

yes, well, I guess you do
those were both under exposed, so the whites came out as grey, but the actual colours were 255 for the first one, and 180 for the second one.

[simmsimaging]

Hey all - sorry for the late reply. Been out of commission for a week.

Luke: I guess I am double gamma'ing my files, depends on whether I'm rendering to 32bit or 8/16bit.

Bear in mind that my goal is this: images that look good, have good contrast, and that appear consistent in Vray (VFB) and Photoshop where I do my post work.

To get this I have come down to this workflow:
32bit:
Max: gamma at 2.2 input at 2.2 output at 1.0
Vray: gamma at various values, mainly well >2.2, "don't affect colours" is OFF.
Saving files via PSD manager to psd 32bit format.
VFB: set to display with sRGB active.

16bit:
Max: gamma at 2.2, input at 2.2, output at 1.0
Vray: gamma at various values, mainly well >2.2, "don't affect colours" is OFF.
Saving files via PSD manager to psd 16bit format.
VFB: set to display WITHOUT sRGB.

* for 16bit, if I use sRGB then in order to get the VFB and Photoshop to show the file consistently I have to set the Max output to 2.2 as well, but then I end up using a much lower value in the Vray gamma setting, for example going from 1.6 or 1.7 down to .9 or .85 etc. In that case I am definitely doing some double-gamma but the image *appears* fine to me so I am not too bothered.


What I would really like is the figure out the simplest setup that allowed me to use Vray like I would maxwell: just look using the gamma adjustment in Maxwell, leaving Max's off, and have things match up nicely between the rendered image as seen in the max FB or in Maxwell render, and Photoshop. It doesn't matter whether I save the output as 8bit or 32bit, it always looks the same in Photoshop. It's nice, simple, and predictable - which is all I really care about.

I did get simple/predictable results with Vray and LWF by using the full LWF method in vray, but then I just got crappy contrast and would spend too much time adjusting white values to highly non-intuitive ranges, using VrayColor to get good blacks, and still doing a lot in post. My new method just seems easier to me, even if it's "wrong"

/b

/b

[ARTECONI-CGI]

Rivoli: I think we both agree that to darken the white is not intuitive anyway. If I think of a white wall I'll probably go and grab color in the range between 210 and 250. You don't look at 128 as a white but a grey color.

Brett: I agree that what looks good is good. The problem is that I want to get it look good out of the LWF for compositing reason. If I start to mess with color mapping and gamma values, it will screw the compositing in nuke then.
And the main problem is that sometimes I struggle to make it look good in linear. mainly lack of contrast and dark tones that you can always restore in post with some grading but that to me always lacks of something. In particular to render believable photorealistic architectural interior scene. A design object is easier to lit, a character beside the sss i think is easier too.

On a test I did recently I've compared mray and vray with the standard LWF. gamma and lut all sets to 2.2.
The scene consists of a bedroom with an override material of a .5 white and a big vray light / portal light out of the window.
mray has only the fg gather on and gives me a greyish but decently contrasted render. vray has bf+lc on and gave me a greish image but without contrast. so to be fair i switched off the secondary and left only brute force for primary. i thought that was a reasonable set up to compare to mray without gi but just fg. the render improved but it is still lacking of blacks. the biggest problem i've notice is that no matter how strong is your light mray will always give you dark, black areas meanwhile in vray the black shifts to grey. if I go with the color picker I can't sample a 0.0.0 nowhere. I need to raise my blacks with the levels in post or vfb and althought i can improve it in post i never feel like that my image is photorealistic 100%. maybe hyperrealistic. colorful and nice but you'll say immediately that is a render.

Meanwhile I remember of my early renders in gamma 1 and exponential more believable. more time to find the right light but more real. and I'll probably stick with it if it was not for compositing reason and because they made me a sort of brainwash with this lwf making me belive this is the way things has to be done. I'm not complaining about vray or comparing it, i think it's great, i'm just trying to find out what I'm missing.

sorry if I'm not posting the render comparison. I did a fast test while I was free and didn't think to save it.

Giacomo.

[simmsimaging]

I would actually say that my main area of problems was mid and 3/4 tone areas. I just could not seem to get a decent range of contrast in that area, even more than the blacks. Blacks you could pump up without much problem, but my mid tones always seemed more washed out.

I was working on a project that needed gold materials and was spending hours trying to tweak the material properties and lighting to get something close to a gold I hit very easily in Maxwell. I just couldn't hit it. Eventually I turned off the sRGB button and realized that the gamma was what was killing it. This was the point when I switched out of the full LWF so I could better control the contrast in my images inside of Max and the VFB.

/b

[rivoli]

yes, I think it's not intuitive, but if you pick any value below 1.0 as white, then it probably makes sense if it ends up much darker once it's gamma adjusted. of course, at the end of the day, whatever works and looks good it must be right

[Deflaminis]

I would actually say that my main area of problems was mid and 3/4 tone areas. I just could not seem to get a decent range of contrast in that area, even more than the blacks. Blacks you could pump up without much problem, but my mid tones always seemed more washed out.

I've been getting around this by doing a sort of light based AO. Using a 200 white override mat with AO enabled on the GI tab, set to a very high value like 5 feet or 10 feet. (Giving the whole scene some elements of AO.) Then comping in post, works quite well.

I still struggle to get those darks and mids with the normal renderer. We tried using a lot white base value such as 153 but it all broken down once we started loading textures in. Getting the junior artists to clamp the texture colors turned out to be harder than expected.

[simmsimaging]

I've been getting around this by doing a sort of light based AO. Using a 200 white override mat with AO enabled on the GI tab, set to a very high value like 5 feet or 10 feet. (Giving the whole scene some elements of AO.) Then comping in post, works quite well.

I still struggle to get those darks and mids with the normal renderer. We tried using a lot white base value such as 153 but it all broken down once we started loading textures in. Getting the junior artists to clamp the texture colors turned out to be harder than expected.

I agree that there are ways to do it in post, but I have found that it's just so much easier and more intuitive to see it in the render stage, so you can build the scene lighting and mood more accurately, and get materials zeroed in better/faster. Clamping textures is just a PITA as well For me, just using the color mapping and burning in the tone mapping and gamma, but still keeping the render as float (so I can adjust the highlights and shadows later) seems to give me the best of both worlds. I don't really feel any loss occurring, at least not so far.

[kimgar]

Getting the junior artists to clamp the texture colors turned out to be harder than expected.

exactly. i can live with the process of darkening materials, there's scripts and whatnot for doing that, but as mentioned it is not a very flexible workflow in a working environment.
there's always why this and why that...

[ARTECONI-CGI]

Sadly, it's nice to hear that I'm not the only one to spot this problem.
The more I go on the more I honestly think there is a mistake, something wrong in the way VRAY approach the LWF in terms of code. as per a double correction on the reflection or I don't know what. As I've said recently I'm using the LWF tick on the color mapping and to me it seems one of the best option. Does anyone use it?

Deflaminis: I've gone your way for a while and in production as well they pretty much always comp an AO pass on top of the lighting / gi but It's always a sort of guesswork. You always have to imagine what will come out after the post and honestly the more I mess up in post the more I think I'm ruining the image in terms of physics (for as much vray can be considered physic). Moreover I think it's easier to get away with it on a movie than on an interior viz.

What you see is what you get is probably the way to go, and Brett seems to have grabbed the concept really well. I still wonder what to do when I have to stay linear....

[rivoli]

as per a double correction on the reflection or I don't know what.

may be worth trying to adjust the reflections to compensate for the gamma shift, if that's the most critical point. like plugging a falloff into a colour correction map, and then in the reflection slot. or maybe a vray colour map and specify the gamma correction?

[ARTECONI-CGI]

Hi Rivoli,

yes I've tried few times but this LWF button in the color mapping seems to do exactly this to my eyes. BTW I'm testing ai interior starting from a white 128 and yes I get more centered values in the histogram. Previously my histogram was concentrated on the highlights but I have to say that the render looks grey. Anyway I am at the beginning, there's room to improve it.

Giacomo.

[rivoli]

I never used the lwf button myself, but it would make sense if it applied a gamma correction to any map in scene.
as for the white being more grey than white, well I guess that's relative. if you expose that as white, and everything is adjusted accordingly, it should work and result in a much more contrasted image.