A few new shaders

I’ve added 3 shaders that may be of use to some folks…

ak_skinoverlay is a skintone line overlay focused on hue, not IRE. Use as context view and it will show an overlay for pixels that are within the skintone hue range, making it easier to align your skintone color. Best used in combination with false color scopes which handle the exposure aspect.

ak_colorcompress is a hue/sat/luma compressor, similar to the Resolve FX. You select (sample) a target color. Then separate controls for hue/sat/luma pull all other pixels closer to this target color. There’s a curve for the effect strength as well. It honors a matte input to restrict the shader to certain image areas.

Often used to remove slight color variations in skin or product.

ak_vibrance is repacking of available GLSL code similar to vibrance control on Resolve. Not too different from a sat/sat curve, but easier to use. Also honors a matte.

Right now these shaders assume that you are working in video (Rec709) color. So you may have to add a ColorMgmt node in front of them. I’m working on a version that supports both linear & video.

Did some basic testing on these the last few days. Feedback and improvement ideas welcome.

Skinoverlay controls:
Screen Shot 2023-08-12 at 7.03.44 PM

Color Compressor controls:

Example of Skin Overlay (may look to improve with some filtering to eliminate the single pixel noise)



I updated the skin overlay. It now supports both linear and video sources, and has a number of filters to help denoise the mask.


These Shaders are very interesting!
But since this skin overlay update, I can’t see the result when I connect the clips and press F4.

Thanks for flagging that. Will look into that.

Did you get any error messages in the terminal or console? If no image shows for F4 there’s most like an execution error that occured, like unknown function called.

Also, are you on Mac or Linux?

I use M2 Mac Studio!
Also, when I press F4, I get the following syntax in the terminal.

ERROR: One or more attached shaders not successfully compiled

dlCheckGLError: Texture::pre-bind()

Thank @ROI.

MacOS didn’t like something I did on Linux. Fixed it and tested both Linux and Mac. Give it another try.

Had to do with the overlay color customization. Removed that for now. The way shaders are written doesn’t make it easy to have color inputs that transition seamless between color spaces. Will get back to that part at some point.

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Thank you! It works fine!

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One more shader addition - the equivalent of Resolve’s Texture Pop effect. Matchbox filter name is ak_texturecontrol

A 5-band frequency separation that can sharpen or blur each band, with range control for shadows, mids, and highlights, honoring matte input.

Pretty straightforward.

Two things to keep in mind:

You can change the blur radi for each band, I’ve started with some defaults that seem to work for me, but we’ll have to see how what the right values are across a wider set of images. If you use the shader and have to adjust the radi, I would love to know the values that worked for you, and the resolution / nature of your image. I can refine the defaults over time.

Also, if you mess with the radi, keep them in an increasing order, each must be bigger than the previous, or the band filter logic will break.

And as before, I’ve done a good amount of testing, but there may be issues or things that need tweaking. Let me know.


Hi Jan,
Where can I find ak_texture inteil please? I don’t see it at logik-matchbook.org. Thanks!

I did upload it to logik-matchbook, but let me check.

@GPM Looks like something went wrong in the last upload (must have overlooked the notes prompt). Just did it again, and I can see it listed now.

Got it – thanks Jan!

Hi @allklier Are these shaders in the Logik portal? I can’t see them

Hi @johnag,

Saw your Discord ping as well. Looks like you found it now. Not sure why new shaders don’t show up in search, I noticed that too. Does Flame build a search index and is there a way to refresh it?

Let me know how it worked for you, after you found it.

Search now working. My default shader path was wrong.

Just a curious question. Can the shader be aware of it being used in Image and if so can the default input be front?

I have to look at that, so far I’ve used it only batch.

I think to be used in Image they have to be classified as ActionFX, but that may be possible.

@johnag Updated the shader so it works properly in Image and also selects the front properly.


Thanks for the update.

Is there a reason I can’t install from the logik portal? I don’t see it in the list. I’m using portal 5.6.1

That may be a question for the portal experts, I don’t know how it builds its list and if it’s based on what is on matchbook? Maybe another cached index either on your system or the portal backend.