Thanks for your detailed answer.
I am trying to produce 'SpecMaps' for a cars livery in iRacing. https://www.iracing.com/painttextures/
It takes the Red value of a pixel and makes the pixel on the car metallic between 0 and 255
It takes the Green value of a pixel and adds roughness between 0 and 255
It ignores blue
https://i.imgur.com/s3AdThB.png
In photoshop it seems possible to take these and only 'paint' an individual colour from each layer/ group, I'm looking for the best way to do so in Gimp.
I am trying to produce 'SpecMaps' for a cars livery in iRacing. https://www.iracing.com/painttextures/
It takes the Red value of a pixel and makes the pixel on the car metallic between 0 and 255
It takes the Green value of a pixel and adds roughness between 0 and 255
It ignores blue
https://i.imgur.com/s3AdThB.png
In photoshop it seems possible to take these and only 'paint' an individual colour from each layer/ group, I'm looking for the best way to do so in Gimp.