A Complex Selection Using Both Colour and Luminosity
Sometimes a selection is more than a simple matter of surrounding, painting and refining. This is an example of how you can use the Black and White adjustment to initiate a complex colour-based selection (sometimes this is all you need), then using Curves to push remaining areas to black or white, plus a masked Fill layer to include the remaining areas into the black-and-white grayscale layer which you can then convert to a mask.
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