Re-creating the $600 Brim Linny LUT in Resolve
The Brim Linny LUT
A few months back the Brim Linny LUT ( https://www.thebrim.pictures/sucomo.html) caught the attention of many colourists around world. Not only because of the "film-like subtractive color model" but also because of the eye watering $607 price tag.
I actually quite liked the effect it had on the sample images. A lot more organic than the standard Arri LogC to Rec709 LUT. And because it's a neg emulation it's a lot more gentle compared to standard film print emulation LUTs.
Like most other colourists I soon forgot about it... That is until a post popped up asking about it on the r/colorists subreddit. The LUT creator chimed in and sung its praises etc. Amongst one of his claims was that there was no way to reproduce the LUT inside a grading app.
So with a spare hour or two, I set off to re-create it. Around 45 minutes later I arrived at the destination you see below.
The Node Graph
The bulk of the re-creation is achieved by two 3x3 matrices. There is no keying, no hue vs hue, no hue vs luma and no hue vs saturation or anything that would make the re-creation only work with the select few example images. The two 3x3 matrices are as broad of strokes as you can get. If it matches one example image, it will match all the others. And it did.
Breaking down the node graph
So breaking down the node graph from left to right. In the first node we have a simple exposure adjustment curve, this can actually come at the end, but I moved it up front as it kept the corrections consistent between all the examples. Then we have a Layer Mixer with the blend mode to Subtract. The top node is setup to invert the image. The bottom node is a 3x3 matrix which is shifting the saturation and luma of some of the colours. The second Layer mixer is also set to Subtract, with the top node setup to invert the image back to normal. The bottom node is a 3x3 matrix which is operating on a negative image. This was the big breakthrough and the bulk of matching the LUT. Without operating on a negative image, I couldn't match it this easily. This is what is adding the saturation to the image, and the correct density to all the colours. At this point the it's about a 90% match. The colorimetry through most of the image is correct and if I was to use this re-creation, I would probably stop here.
But to get a better match we're going to do two more corrections. So next up we have a Luma vs Sat curve that gently desaturates the brightest part of the image. Followed by a Sat vs Sat curve that keeps overly saturated colours in check. And thats it.
The transforms for the first two samples are identical. Apart from adjusting the exposure, there where no other tweaks. Sample 3 has tinting in the highlights and shadows to match the original film scan the Brim Cinny LUT was trying to match. Plus a slight tweak to one of the 3x3 matrices.
For the heck of it I've added another image to the end of the first two samples where I adjust the hue vs luma curves to get a closer match. It's probably a little too form fitting to the available examples, so I don't consider it a valid correction.
In all these samples we start off with the base standard Arri LogC to Rec709 LUT, then the Brim Linny LUT, my re-creation and then ending with the hue vs luma cheat version.
Open them in seperate tabs and flick back and forth to see the differences. Remember I'm trying to do this as broad stroke as possible. I could get identical matches if I endlessly tweaked curves etc.
All images used are available to download from CML: http://cinematography.net/compare.htm