Color explained

[glorybound]

Does anybody have any literature a client can read on color? Something not to techie. I have the hardest time explaining to people why that little paint chip that they are holding up to the rendering doesn't match 100%. I explain the whole shopping for carpet and how it'll look different in you living room then in the showroom. Or I use the put a red carpet in a glossy white room and your walls will look pink. Then I usually get people wanting renderings without any color variances.... what to do?

[joconnell]

yeah it's an awkward one - there's a question on cgtalk regarding the same. There's no consistency in displays of any kind at all and people's preferences for brightness and contrast on tvs / computer monitors etc will throw things further out of whack. What's the final medium for the images - print or screen? If it's screen then you've got a huge amount of variables. For starters you have the monitor calibration to make sure it's accurate and correct, then you also have the lighting in your room - as you know since the sun and sky change colour at the different times of the day it'll have an effect on the way colours look in your office if you've got any windows or if light is coming in from outside. Ideally you'd have a sealed controlled environment with consistent lighting like a white office with daylight bulbs so you don't go mad - it'd mean that when you calibrate your monitor you'd know that no other lighting factors in your work environment will change at all. for example in commercial grading suites where they do colour grading of films or tv ads they normally work in a blacked out room with very low task lighting so they can just about see what they're doing but it isn't affecting their colour work at all. They pretty much work like bats. Then after that you've got the fact that if a client views it on their monitor there's no chance it'll be calibrated the same way as yours so the chances of a swatch matching both is nearly none. you can only really hold up the swatch and judge it by eye using the colour balance in photoshop.

[pixelstudio]

Aaahhh a very common problem to me!!!

Well maybe you are like me and am trying out a number of different techniques to do renderings, such a LWF. using HDRI, different lightsetups and such.
Well i do also, and i realy like trying out new thing. But

My boss has some hesattation for using for example HDRI or vraysun, simply cause of the effect it has on the colour's of the image. if a client says "Doors are RAL9001" and it looks different then white cause of HDRI light or bounching GI or vraysun we get feedback that the colours are not correct. We know what i causing it ( and find colours are correct but clients don't see that.
So often we are going back to techniques that don't affect colours that much. it's a bummer but well. what to do about it.

[RErender]

It might be interesting to take photos of jobs that you have done after they are built out. Then you could compare the color swatches to "real life" and demonstrate in real world examples what is happening.

Perhaps some illusions to demonstrate just how fragile our perception of color really is.

http://www.popularscience.co.uk/features/feat16.htm

http://www.coolopticalillusions.com/...minescence.htm

[crazy homeless guy]

this will always be a problem. the best luck we have is to provide a sample board in addition to the rendered images.

but as for the image itself, the 3 vital things for making the material look correct that i use.

- work in LWF, this elimnates extra color bleed in a scene.

- use Vray physical camera, with the white point properly balanced. this counteracts color shifts in a scene.

- make sure you rgb values of the material are as close to spec as possible, and that anything that needs to be gamma'd to match your workflow, is properly gamma'd.

____

edit, forgot to mention, make sure you monitor and printer are properly calibrated using a spectrophotometer or densitometer.

[Sawyer]

Take a color swatch and photograph it in a room then take the same swatch and photograph it in the sun and in the shade. Put these 3 swatches together in a psd file and add the online color swatch from a sight like

http://www.colorcharts.org/ccorg/

[glorybound]

RGB Match

The above illusions are amazing.

I can honestly say that I am not getting this gamma stuff. I watch DVD's like "Gnomon - Global Illumination Exterior" and he is getting great results with his gamma at 1. I run his scene and I need my gamma set to 2.2. I read threads here how they are getting great results with color mapping linear at 1,1,1, but I have no clue how they are accomplishing this. My monitor is calibrated and it is gamma 2.2 so should I assume these peoples monitors are gamma 1? I should get the exact same results with a monitor of 2.2 and color mapping gamma 2.2, correct? This is as long as my maps are also gamma 2.2? This to me is linear work flow (LWF) as long as they are all same you are working correctly.

How do I know my materials are gamma 2.2? In v-ray I can tell my v-ray color to be 2.2, but when I create a map in Photoshop or download something I how do I know what gamma that is?

[joconnell]

In that dvd he was using the colour correction curve in the vray frame buffer to get the same effect as using a gamma of 2.2

[ene.xis]

and he prob is saving the render to an exr file wich will aply the 2.2 curve when opened in photoshop for example.
in fact he is using linearworkflow, and keeping the gamma on 1.0 untill post-production app!

[Dynedain]

I recommend buying the book "The Art of Color" by Johannes Itten. It's small, thin, and a great reference.

It also makes it easy to pull out examples for clients to show them. Such as how the same color can look different with different backgrounds.

[glorybound]

Color

In the DVD he is showing the VFB and he has gamma set to 1, but he is raising the dark multiplier to 2 and the bright multiplier to 1.5. I tried this on his supplied scene, but I still need gamma set to 2.2. He doesn't have the Srgb check and I don't think he has a curve applied.




I'll check out that book.

[crazy homeless guy]

Re: RGB Match

My monitor is calibrated and it is gamma 2.2 so should I assume these peoples monitors are gamma 1? I should get the exact same results with a monitor of 2.2 and color mapping gamma 2.2, correct? This is as long as my maps are also gamma 2.2? This to me is linear work flow (LWF) as long as they are all same you are working correctly.

i think you set the gamma's in your preferences to be equal to what your monitor is calibrated to. so this basically cancels out the gamma you have your monitors calibrated to, and makes max behave with a gamma of 1.

not sure if that is correct, but i think that is what is going on.

[glorybound]

gamma

My understanding is max's gamma is for max's frame buffer. It also handles incoming textures.

[crazy homeless guy]

let me edit what i said after a little reading.

max, be default, is set up to work with a gamma of 1.0. my monitor is calibrated for a 2.2 gamma. so i would guess that the adjustment in the max preference file compensates for my monitor, since it displays 2.2?

you were right.

[pixelstudio]

Crazy home guy : if you want to save images as TIF or JPG the output gamma should also be set to 2.2 right?

Now for the workflow with this preferences.
- All bitmaps are gamma corrected cause of the input gamma setting what will adjust all incomming bitmaps with an gamma of 2.2 so textures are fine.

- Affect material edit and selectors are for visibility in max only .... ? cause
people are adjust the diffuse colors. i have seen two different ways.
1. Colour correct and set 2.2 gamma on a diffuse color.
2. Use the .255 value for adjusting the values
Reading this forum more people are saying methode 2 is the 'best'

- Now what remains are material reflection/refraction and light colour values and such. i'm not sure what to do about those. refl and refr colours can be adjust with the .255 methode. but i'm not sure about light colour values. (there no map slot somewhere right? )

Hmm after reading what i type, i say texture are corrected, and the .255 is the best methode for adjusting diffuse's. but .255 isn't the same as gamma 2.2. so textures and diffuse are getting correct not the same. so i guess i'm wrong.

Hmmmmm i need to do more reading.