New compositor mix types
Aug 21st, 2008 by admin
As I prepare The Beast for its web release, I’ve been looking for a way to make the standard Blender render look a bit more film-like through the compositor. I came across a great method using Photoshop that was devised for making digital stills appear more like their film-based counterparts. I prepped a couple of frames directly in Photoshop, and it gave a nice effect. Unfortunately, Blender’s compositor was lacking one very important Blender method: Soft Light. A little Google-fu turned up the proper equations and a little poking around in the sources and begging on irc turned up the proper portion of the code with which to fiddle.
Soft Light is a blend method that is particularly suited to colorizing and grading images. It has other uses (balancing luminosity, for example), but I’ve mostly used it for tinting in my career as a Photoshop professional. The “film look” procedure called for heavy use of this blend method, and I found that there was no decent way to simulate it in the compositor. So, a little work and it was done. Pictures are below the fold…
Patch in the tracker:
Here’s a raw frame from The Beast (click for 720p HD):
Here is that same frame colorized by blending a solid RGB blue (in the first) and orange (in the second) into the image with a Soft Light mix node (once again, click for 720p HD):
Other blend methods tend to ruin the existing color. Soft Light does a great job of retaining the look of the original while tinting it. If you’re considering any serious color grading with the compositor, a Soft Light blend will be give more natural looking results than pulling curves.
And now, consider this node network:

This takes the RGB image and tone-maps it so that shadows are purple and highlights are orange. Blended back into the original image with a Soft Light mix node, the result is this really cool color graded image:
And finally, another raw frame from The Beast, followed by the more filmish effect I’ve been experimenting with. Note that, as complex as it is already, this effect really wouldn’t be possible without the convenience and natural color blending ability of Soft Light.
Raw:
Composite:
If you didn’t click for HD on the earlier ones, you should really click on these two. The difference is substantial.
Okay — the odds are the none of you have been clamoring for a Soft Light mix type, but hopefully this little set of samples may have awakened you to its super useful… um… usefulness. So, if you think this is cool, you could do worse than bug someone to make a build with the patch, give it a shot, and post your artwork.
Next on my list (tomorrow if I get time), is to add the Linear Light blend type. That’s a necessary pre-requisite for a true High Pass filter group in the compositor, which I’m sure lots of people would find useful (high pass is an image, inverted and blurred, then recombined with Linear Light at 50%).






very nice work. are you posting the pynode script anywhere for others to test?
Actually, it’s not a script. The new blend nodes are coded directly in the sources and are available as a source patch.
is this planned for inclusion in 2.47? is the patch available online?
[...] | user-saved public links | iLinkShare 3 votesNew compositor mix types>> saved by zupernano 0 days ago1 votesTao Te King (o livro chinês do “dharma”), v. 22>> saved [...]
Thanks for the Blender nodes setup info. Soft light is a tricky thing for me. I typically do the editing in GIMP.
[...] working on some image processing projects in the node compositor, namely the previously-mentioned Soft Light and Linear Light nodes, and something new: Screen Space Global Illumination. It’s not even [...]
very cool, Harky! Glad to see you haven’t been hibernating in your HarkeyCave. This is a very cool post-pro node that will save endless hours fiddling with lights and gamma and such. I think different color ramps may emulate different film stock and the tone low light and high light is captured in. It’s very nice bringing out flesh tones, and also blending in ambient light in the shadows. And that is an ugly baby!