I have an image that is a logo; a word written in a single solid color but the edge pixels of the letters originally had some transparency
The original was lost and now all I have is a version of it that has a white background. This image is thus predominantly either white (RGB html code #FFF, say - appreciate it would be #FFFFFF but using 3 characters for brevity/clarity) or pure red (#F00, say) but the edges of the letters have a band of pixels that are somewhere in between, such as "very white reds" #FEE or #FCC down to "very red reds" like #F22 or #F11
I wonder if there is a process that can paint the whole image as red #F00, but have an alpha component that is "how proportionally close to white the pixel was" or said another way "where the pixel color falls in the range #F00 to #FFF, determines how transparent the red needs to be (when laid on white) to look like the pink it does now"
I know how I'd do it if I had to code it up myself in C# (basically the maths of the above, to work out where the G and B values fall in the range and use that as the alpha component percentage), but is there anything out there technique wise that can "find and replace my red-with-white pixels" with "their equivalent red-with-transparency pixels" ?