on Dec 18, 2017 at 10:24:43 am Last Edited By Michael McCune on Dec 18, 2017 at 10:59:28 am
LAB color nodes offer advantages and looks that are useful and appealing. Usually setting up nodes and adjusting the LAB A & B curves works well. And LAB A & B can also useful in splitting chroma (A & B) and luma (for sharpening, for example). Most of the node tree is in RGB.
And of course one common and constantly-used tool is the eye-dropper with the "Show picker RGB value" selected.
But lately this -- within seconds -- reliably crashes the program. First the cursor does not change to an arrow when moved out of the viewer pane but remains as an eye-dropper. This situation means it will crash within a second or two.
Of course we all know that this stuff is magic--shifting from one color space to another on the fly, from node to node, must make a mathematician's head explode.
I have no answer for the crashes -- so much depends on hardware configurations and source formats -- but if I need to do something like this, I set up three parallel nodes with keys set to grab specific luminance bands. Top one for highs, middle one for mids, bottom for blacks -- and then adjust those accordingly. You could also use a YUV splitter node to sharpen just luma only.
The new ResolveFX Sharpen Edges and Soften & Sharpen plug-ins also allow some very tweaky kinds of sharpening that are very good at excluding everything you don't want to grab. I tend to use these in combination with tracking masks for certain soft photography issues.
I specifically don't use LAB because it slows me down too much and I'm generally on a pretty tight schedule. I could see it being used to create a prefab look for a very, very specific situation, but beyond that, it's too "fiddley" for me.