How can I convert a grayscale value (0-255) to an RGB value/representation? It is for using in an SVG image, which doesn't seem to come with a grayscale support, only RGB...
Note: this is not RGB -> grayscale, which is already answered in another question, e.g. Converting RGB to grayscale/intensity)
The quick and dirty approach is to repeat the grayscale intensity for each component of RGB. So, if you have grayscale 120, it translates to RGB (120, 120, 120).
This is quick and dirty because the effective luminance you get depends on the actual luminance of the R, G and B subpixels of the device that you're using.