Join us this week on Logik Live as we kick off a special two-part series all about Matchbox Shaders! These powerful GLSL shaders are a must-have for any Flame artist, offering limitless possibilities for image manipulation—from color grading and texture generation to skin retouching and additive keying. In this episode, I’m excited to be joined by two expert Flame Artists: Sinan Vural from Oslo, Norway, and Vermont’s own Andy Dill. Together, we’ll explore some of their go-to Matchbox Shaders and how they seamlessly incorporate them into everyday compositing tasks. Tune in to discover new tips and tricks that could transform your workflow!
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Exclusive Post-Show Q&A
After the show, Patreon patrons will continue the conversation with Sinan and Andy over on Zoom to dig deeper into Matchbox and answer any questions or dive deeper into subjects that we didn’t have time to cover during the show. If you’d like to support what we are doing with Logik, get access to exclusive content and earn yourself a Challenge Coin, consider becoming a Patron at http://patreon.com/logiktv
We’re LIVE on YouTube TODAY, November 17th @ 2pm ET
Like many techniques in flame, it will sometimes work flawlessly and other times not work at all. I like it because it’s a very fast technique to try, so when it works you save hours of paint time, but I still do plenty of edge painting.
Before you go all out on paint, use a Mastergrade node, set the color sampler in the spill region, go to the H-H and H-S curves. Set new points (using A+click) left and right of the guideline from the color sampler and drag in the respective direction. In some cases you may need a lose gMask around the whole region in case the spill color shows somewhere else in the frame.
That should work pretty well regardless of dark/light background.
The reason Andy’s version works better as much as I can tell, is because the Look node neutralizing the skin tone takes it out of consideration when you then do any color suppression, because neutral colors don’t have any color information the color suppression algorithms can discern. That allows you a more liberal selection of the spill color which then makes it cleaner.
The Mastergrade curves without the neutralization trick work, but have to be tighter margins, which means they will miss some elements and the result is not as solid.
(spent some time with Andy’s setup last night trying to understand why it works so well)
As you can see the main spill region looks decent. But there’s a fine purple line left in the transition zone where the curves cannot pick up the spill color reliably. Signal to noise is not big enough.
I had overlooked the curves in the master grade but used them recently and found them to be far superior to the old colour curves I was used to.
I loved seeing @andy_dill ’s trick. Surprising use of the look node, taking advantage of the invert option. It reminded me of a trick I saw for pulling a key.
I have always found the colour curves to be a little twitchy and hard to refine. I think Andy’s trick works so well because is puts the image into a place that the colour curves are really good at handling. By removing the subtleties and cranking the saturation, colour curves has an easier time and then you can invert back with only the blue/magenta spill effected. Fantastic. Can’t wait to try it out in the field.
@andy_dill I notice that you put the entire image through the process of 4 Looks and the Colour Curves. Do you ever try to just replace the effected area so that the whole image isn’t stepped on? And I just familiarized myself with the trick and it’s really great. I can’t wait to get a shitty blue screen to try it out on for real.
And even though you can copy/paste these channel values, for some reason linking them, and particular ‘link & negate’ doesn’t seem to work. The frustration of an inconsistent UI - Ugh
If you have a few artifacts left, you can even them out with the AK_ColorCompressor matchbox. Sample the skin color and nudge the ‘Hue Compression’ with a light touch. Don’t overdo it.
What this does is takes all the pixel and pushes their hue towards your sample color. So if you have a few pixels off from your target skin color you can reel them in ever so slightly.
But it will affect the whole image, so you need to mask the area. And if you set it to 100% you get a flat even color, which is too much.
That matchbox could also come in handy on @Sinan’s infill trick. Where he ended up with all the infill color, but there’s just some color drift going on, you can even the color out a bit with this matchbox.
Haha. Not usually, or at least not at that stage. With most phone-type comps I’ll use some variant of the screen matte to just comp the area inside of the screen, but that’s usually it. I’ve found the look nodes to be reasonably nondestructive in most cases.
Be sure, when using this to always pull a new one out of the bin. Never copy one that is already in the batch. The expressions will remain linked to the original when you do that.
Exclusive Post-Show Q&A 
We’re LIVE on YouTube TODAY, November 17th @ 2pm ET 
