Color temparatures, sky color, ect. and COLOR SPACE

[pailhead]

double post

[pailhead]

Any idea why is it so blue without any of the gamma nonsense?


Are you saying that by default, its too blue and saturated, and that you need to wash out your images and your color settings by applying gamma to your images?


This is what max shows by default. It's pretty blue, its by default, it's something everyone would get.




This is what it shows when i apply 2.2 gamma to it, something that most people don't know how to do or don't understand (myself included). Meaning - you need to tamper with a lot of confusing settings in order to get an image like this instead of the first one.





*edit*


for instance

if i take the first image and increase the gamma in PS i get something thats almost the same as image #2.




You are saying that this is actually correct.





If i were to take a normal image:



And do the same thing:



The result would obviously be wrong..


Are you saying that simply increasing a gamma in an image which has an 8000K IES light in it will make it appear correct, while it's obvious that if the same thing was done on any other image, it would look washed out?

[ruud3dv]

This is because you first tell max your display uses a gamma of 2.2

If you want to see what no gamma correction does, you should also disable the gamma setting in Gamma and LUT, because LCD displays have a gamma closer to 1.0.

Here's a quick test i did with 6500K versus 8000K, neutral whitebalance, gamma correction of 2.2, adaptation only. Bright white gamma-corrected material. To me this looks quite accurate.

[pailhead]

Can you do the exact same test but with everything set to default. No gamma/lut in max, vray or anywhere else. The same image, same settings, 6500k vs 8000k, but without any gamma modifications.

Just as if you had done a fresh install of max, and made a new scene with some lights and these two color temparatures.

[ruud3dv]

Yup:

- Max Gamma disabled
- Vray Color Mapping: Gamma Correction 1.0, everything unchecked
- Material bright white 255.255.255, no gamma correction

The top one is vray framebuffer, with view in sRGB-space checked
The bottom one has it unchecked, this is the same result as the max framewindow.

Must say i expected the top image to look like that without sRGB-button on.. but somewhere in my head i must've taken a wrong turn, it's getting late i think

Time for the real experts to have a say about it me thinks

(note that for these examples i didn't aim for proper exposure, just wanted to see the difference between the two lightsources)

[pailhead]

There's nothing to say. Kelvin temperature colors, as well as vray sky and sun should be gamma correctable...

[ruud3dv]

In this thread i posted two pics that use the 'LWF' = Lele's Work Flow
http://www.chaosgroup.com/forums/vbu...ad.php?t=38783

I didn't have to correct anything in post, not even the background, these are straight renders with Sun and Sky multiplier on 1.0.
To me it looks like the sky isn't washed out and is properly contributing to the scene-lighting and reflections.

Can you post an example of a picture where you end up with a washed out sky, together with your settings?

[pailhead]

Can you do the exact same test but with everything set to default. No gamma/lut in max, vray or anywhere else. The same image, same settings, 6500k vs 8000k, but without any gamma modifications.

Just as if you had done a fresh install of max, and made a new scene with some lights and these two color temparatures.

Do the same, but with a vray sky this time.

[ruud3dv]

I'll run a test when i have some more time, working on a tight deadline atm.
But the link i posted to the thread with two images i did earlier shows clearly there is no mismatch between sky and lighting, nor a washed out look of either the model or the background, which was the complaint in your first post.

There's a difference between your workflow and mine though. You're gamma-correcting your textures with 2.2 (or a multiplier of .454), while i am darkening them even more, rgb-multiplier of around .255 for most textures, as per Lele's measurements with VraySky and VraySun. And, when using a VraySky, your background should be colormapped just like the rest of your scene, so you need to check 'Affect background'.

[pailhead]

No corrections, straight out of the box, this is what you payed for, this is what you normally would get. If you had never came across that gamma tutorial, or Lele's method, or Chris Nichols dvds, you would have been under the impression that this was correct:





However, you started playing with gamma, lut, .255 rgb multipliers (this is something that i totally don't understand), and now you believe that this is what your skies are supposed to look like.

[ruud3dv]

Hehe, good thing those tuts are around

I get your point though. But if with using a certain workflow and settings you still need to change the background for every render, i'd rethink my strategy. In the end it's all about what looks right to the artist/clients, it's no absolute science. It doesn't need to be physically accurate if it looks photoreal.

Baseline: for me it gives good and quick results, for almost every type of scene. Here's an quick and early WIP straight from the framebuffer with same workflow, i don't think the sky would look better with even more color in it.

Greetings, Ruud

[voltron7]

Linear Converter

pailhead, if you simply want an easy way to "correct" the color of those lights, try the free application floating (no pun) around called "linear converter" I think from Westlund Studios?) It doesn't get down to decimals, and for colors very close to black or pure white, it might not help, but it's really handy I've found for correction colors with no plug-ins (i.e. CC or Vraycolor.) By the way, i forgot who uploaded it, but thanks a million! If I can, I've been trying to use it for things like paint colors that get washed out. These are just my opinions and I know this "LWF" can be a very touchy subject, so please don't flame me guys 'n gals, just trying to add a helpful suggestion.

[pailhead]

It doesn't need to be physically accurate if it looks photoreal.

But this is very very subjective. I only took a glance at the .255 theory (can't open the original thread) but i for one, never had a problem with my skies being too dark. If anything, they always seem overexposed IMO.

The bottom line is, it seem sto me that i am given an alternative by being able to choose any gamma while loading an image, plus having vray color with a gamma parameter... not to mention the color correct plugin.

The only things that i can't color correct are vray sky, vray sun, and now IES colors (be it in kelvins, or actual RGB color).

@voltron7,
Can you upload the app again?

[voltron7]

link

Here's the original post, sorry, I don't know if I may re-upload it without permission, etc.

[gilpo]

@voltron7: Good to know people are still using my little app. Making it output floating point values and decimals is still on my list of things to do, but it's not a high priority as we don't have a use for that feature internally. I've got to do the work we get paid for first .