>>1468239You only lose detail if you don't know what you're doing.
My tip, for whatever worth they may have, are;
1) Don't use pure black. Dark greys, browns and possibly purples and blues work far better.
2) Just like the skin to retain detail make a duplicate layer of the image you're colouring, desaturate or colourize it, set it to multiply and link it to the hair mask. Maybe repeat this but set the layer to hard light or overlay if the result is too dark.
>>1468256I use Photoshop, personally. I've tried GIMP but the lack of soft edge brushes is kind of a deal breaker but maybe that's changed since I last used it. As long as the program has: Layers, masks and the ability to set layers blend modes you're in good shape.
