I know how to merge individual channel images in photoshop, but I can't seem to find a tutorial or even mention of how to achieve this with video clips. I have satellite footage shot at different wavelengths (R, G, B). I could take single frames and easily make images but I'd love to do a false color video. I guess I could do all of the frames individually but I'm curious, is there a way to do this in Premiere or After Effects? Any suggestions would be helpful.
I would put all three files on three layers in either Premiere or After Effects, and play with the different blend modes and opacity of each layer until the image looks right. Screen, Add, or Overlay modes will probably be worth trying.
Just to build on @tomh answer, to get false colour you will first need to get true colour by added the layers in after effects, use the "Add" blend mode as mentioned, which will get you true colour (rough enough without grading).
Not sure this is exact "false color" but it will work near enough for your purpose I think:
You will need to select all 3 layers and pre-compose them.
Then go into Photoshop, create a blank, empty document of the same size as your footage.
At the bottom of the layers panel, create a new Gradient Map adjustment layer.
Select a gradient map that fits your requirements, or create your own. This is what will map light and dark values to colours.
Now you can export the gradient map as an LUT:
Go through the save steps and note where you save the LUT files to. Back in After Effects, you can add the "Lumetri Color" Effect to your pre-comp, open the Effect, then Basic Correction, then on Input LUT click Browse and import the LUT you just created.
Your footage should be gradient mapped to the LUT you created. Hope that helps!
EDIT: couple notes, the
.3DL files seem to work best and go for about 60 grid points. Can add LUT's in After FX or Premiere Pro.