Help - Color management in maya 2016
I am really confused to anything related to linear workflow, I have been trying to understand it by watching videos on youtube, I thought if someone who has experience to everything related to rendering would maybe chat with me privately that would be great in order to help me understand the process, and here I am posting this wierd request on polycount, so.. if anyone would like to help me msg me privately
P.S
Q:Why won't you just write your Q's here?
A: I have got too much of them and I would rather just to do this privately, this is wierd, I know
P.S
Q:Why won't you just write your Q's here?
A: I have got too much of them and I would rather just to do this privately, this is wierd, I know
Replies
Wish you luck into finding people who can explain it simple with the appropriate words.
Usually without a linear workflow the highlights are over burn, considering the real amount of lighting, with linear workflow you correct that too.
There's nothing complicated, Maya already corrects the viewport and the Hypershade Material Viewer so that what you see, is what you render (you can turn both off if you want, or change the gamma value). On the other hand, the Attribute Editor shows a non corrected preview, but since it's quite small I'll consider that irrelevant.
Your request is against the purpose of a open forum, so, don't ask for personal messages about your issue.
Why does linear workflow even exist?
I have seen an explanation by Digital tutors on Color Management which is related to maya 2015, now in maya 2016 its quite different, so here are some questions related to that:
1) From what I understood all lights are in a linear colorspace from the first place, is that true?
2) is scene-linear Rec 709/sRGB is linear or sRGB?
3) DT explained you should gamma correct using a node that is designed doing so the colors of each material, does it include the colors black or white?
3) DT fixed a normal map by setting its color space to linear, but they said that all jpgs, tifs, pngs etc are in sRGB color space, how does it fix that? if maya wont downgrade it, the gamma curve will be doubled, wont it?
4) when maya encouters a file in sRGB color space does it downgrade it to a linear color space?
5) Output transform is the tab which transforms the output (the render) to the inserted color space?
6) View transform just changes the transform to the inserted color space?
7) is it safe to color pick from the viewport, will the resulted color in the render will be the one color picked?
8) Rendering space is the color space the render is calculated at, right?
9) question 3 related to input color space rules, and in general to fixing materials for linear workflow, how does that process work? does maya just recognize an sRGB and downgrade it (assuming I insert sRGB as the color space) to linear color space?
One thing I've noticed with Maya 2016 while using Renderman (although I wouldn't be surprised if this applied to other renderers) is that the color picker has "Color Management" turned on by default, which doesn't communicate with Renderman's default "linearize colors" option, which causes procedural textures to look darker than what you initially chose. Just turn off Color Management and you should be good to go.
this is a good source, but just a question, how do you reapply the gamma compensation at the end? (target gamma)
2) It's sRGB, it's used to "linearize" the color space by neutralizing the curve introduced by the monitor.
3) Because it's not used to render any color information, so you don't need to color correct them. For standard texture, you have to leave them as they are. If it's not corrected you'll get the wrong result.
4) Usually a 8-bit texture it's already on sRGB, Linear is used for 32-bit pictures, like high dynamic range backdrops.
5) Yes, but if you have already using the global setting, it will apply the color correction again, so don't do that.
6) Yes, for the rendering it's an override.
7) This depends on how the lighting is set up, you can't get the same color of the color picker with random lights. The color in the color picker is the same you see on the Hypershade view, unless you ticked off Color Management.
8) Yes, if you change that, it will change the whole color space
9) When you load a picture, you can change its Color Space on the Attribute Editor, usually color textures are saved in sRGB, and that's the default color space that Maya uses, so that they are read correctly.
If I made some mistakes, please feel free to correct me.
Why are there so many color spaces?
- Color spaces are 3d spaces described relatively to a reference space that encompasses all human color vision. These are usually either XYZ or LAB. Because all of the mixing and rendering is maths, each tiny variation in size of a given color space will give different results in the maths.
Imagine having two different 3d cubes and finding the center point of both of them. If their sizes and positions differ, it makes sense that you get a different result for the center point, right? So each color space has a slightly different result as well.
Why is there linear workflow?
- Linear is actually the default way of handling and measuring colors in real life. Rather the question is, why is there gamma-corrected workflow, and the answer to that is: Humans have logarithmic senses when it comes to our senses' response to light. This means that an 8bit linear image looks like it has really nasty color banding artefacts to human eyes. We have gamma-correcting/encoding to work around this. Linear workflow thus exists for those situations you need physically correct input for the physically-based maths, such as a physically-based renderer(PBR). The workflow itself is actually a lot easier once you get around the scariness of the toggles, and once you realise all the program actually needs to know is whether to linearise the image you gave it before using maths on it:
* Mark sRGB albedos you made in your favourite graphics editor as sRGB inside the program. The conversion will then be done internally.
* Mark linear space images with linear, this will prevent any attempts at linearisation.
* Mark images that don't hold color data, like normal maps, height maps, metalness maps, as either non-color data, raw data or linear, to prevent any color management to be applied to it, because in this case it is not about how the color looks, but rather about its specific RGB pixel values which then can get converted to a vector or variable.
2. RGB colorspaces can be seen as 3d cubes. But instead of saying they have an X, Y and Z, we instead say that the have an R, G, and B. And each coordinate within this cube thus corresponds to a color. So asumming that the size of our cube is 10,10,10. 50% grey is at 5,5,5.
Using gamma correction node, you convert the gamma-encoded RGB values of a diffuse or albedo to linear coordinates. Thus, our middle gray in sRGB will be linearised into a linear value. So 5,5,5 becomes through this function 2.1, 2.1, 2.1. This prepares it for the PBR functions and will give prettier results.
However, there are situations, like heightmaps, where you aren't actually painting colors, but rather you are mapping values. 50% grey in a heightmap means "50% elevation of the maximum this (displacement) shader can output". It would become really weird if you would make a heightmap and stick it into a gamma-correction node before sticking it into a displacement shader, because then Maya will turn your carefully chosen 50% grey, and thus 50% elevation, into 21% elevation.
Other non-color data images, where you or a baking device carefully selected the right numerical value, would also be affected by such a thing, so for example, normal maps and uv-displacement textures aren't showing colors, but they are showing vectors, and you do NOT want Maya to gamma correct those, so hence why you say it's linear(or avoid the gamma correction node).
Edit: I made a little rundown of what is going on under the hood for the krita docs here, maybe it'll help: https://userbase.kde.org/Krita/Manual/ColorManagement#Linear_and_Gamma_corrected_colours.
What you need to realise is that the computer doesn't see colors, it only knows the coordinates, and it uses those coordinates in rendering maths. For pictures that are genuinely color, you thus linearise to get prettier and more correct results, for images that actually represent numbers, like a heightmap, you don't linearise, because you want the renderer to use the precise coordinates you picked.
also, if you use maya, when using sun and sky in maya 2015 there was a node created which would automatically connect to mia_physicalsky1 which was named mia_exposure_simple1, any clue what happened in maya 2016? I am reading about color management with the physical sun and sky and it appears to not exist in maya 2016 when creating the physical sun and sky,
also should I move on and learn how to use the MILA material? currently I am using the mia material
Officially, normal maps and similar textures need to be assigned 'non-color data', which is a special space to indicate that color management should keep its grubby hands off the file. According to this page: https://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2016/ENU/Maya/files/GUID-631C665F-3092-4B2B-90B7-2A94158870C9-htm.html (which is about something different, but does answer which space should be assigned to normal maps) the non-color data space in maya is the 'raw space', so assign the raw space to your normal maps.
The issue with assigning a random different space is that there's still a chance that the color management does little tweaks to the file, like white balancing or minor conversions. Setting it to linear is thus the next best thing if there is no defined non-color data or raw color space. However, to be certain to stop color management from doing ANYTHING, a non-color data or raw color space is the prefered assignment for normalmaps.
Good luck!
Don't know how I missed this checkbox
Thanks!