RetroTINK-4K Profiles Instructions
Custom shadow masks are stored as 32-bit RGB
BMP files (yes, it MUST be 32-bit, not 24-bit). If you are using Photoshop,
this should be one of the options in the save dialog. The maximum size of a
shadow mask is 16 x 16 pixels.
The shadow mask image represents a gain
factor that is applied to the output image. Mask pixels with the value 128 do
not alter the underly image while value 0 performs a complete mask and value
255 performs a gain of 2x.
output_pixel
<= (mask_value/128)*input_pixel
The RT4K mask engine supports full RGB
operations and treats each color channel separately, allowing for complex shadowmasks or aperture grilles that closely mimic a real
CRT.