Color Mapping After Rendering

[Jer25]

If it's possible to change the color mapping after your render finished I think that would be useful to have less test rendering. (At least for people that don't know exactly what they are doing).

[instinct]

Well you can color map as you wish in post when rendering to float images. The reason why there's also integrated colormapping is that it is also used during rendering to assist the adaptive sampling. So when changing color mapping in post massively you will most likely face noise problems and have to re-render with different color mapping settings anyways. Would be nice to evaluate before re-rendering tho admittably.

Regards,
Thorsten

[sv]

I thought you could do this with the VFB, or am i missing something?
Just use the colour correction controls, and match these graphs:

The Reinhard color mapping does not apply any gamma transformation on the result. Here are some curve graphs demonstrating how different color mapping modes work. The x axis is the input (original) image color, and the y axis is the output (color-mapped) color.



Useful observations:

• In the last image, although this is not clear from the limited graph window, neither the Exponential, nor the Reinhard with Burn 0.0 curve ever go above the 1.0 (white) value (e.g. no burnt-out areas). However, the Exponential graph goes very close to white very quickly, while the Reinhard curve is more gradual.
  
• Near the dark colors, the slope for both Exponential and Reinhard modes is similar to the slope of the linear mapping, which means that those modes preserve darker colors near their original value.
  
• When the Burn value is 0.5, the Reinhard curve intersects the y=1 line (the white color) when x=2 (the original color has an intensity of 2); when the Burn value is 0.2, the curve intersects the white line for x=5; the same relationship is true for any other color and allows you to choose presicely the values of the colors that you want to be mapped to white.

Here are larger versions of the images:

http://www.spot3d.com/vray/images/re...ard_burn10.png
http://www.spot3d.com/vray/images/re...ard_burn05.png
http://www.spot3d.com/vray/images/re...ard_burn02.png
http://www.spot3d.com/vray/images/re...ard_burn00.png
http://www.spot3d.com/vray/images/re...xponential.png

Best regards,
Vlado

But as thorsten rightly points out, the sampling is done based on your settings, so messing around too much can tear the image apart...

[Jer25]

Thanks for the info.

[3LP]

Hi, thoses curves are really intresting...

Does someone hase copied thoses curves info curves files for the VFB? Can someone post them here as file so we could save them. And in the same idea, does thoses curves has been done by someone in afx? And could thoses be saved as comp file so we could use them as well? Otherwise, I will just try to replicates them by hand.

Really nice to know that anyways.

Thanks

Stan

[LarsSonparsson]

Thare is also this free AE plugin for tonemapping. Works well, but is kinda slowish.
It has Reinhard mode build in.

http://www.3dcg.net/software/atlas