I keep trying to color edit the image with the Rotating Colors tool in GIMP, but it will only effect the hair and skin. I have tried only images where they are wearing a white shirt and it still only effects the hair and skin. I am trying to avoid Selection Tooling around all the fine hairs.
It does not target the hair and skin. It targets saturated colors. That tool rotates the hue of a color. Lets say A to B
Because the shirt has no saturation, it can not rotate it. C to D.
You need to mask the shirt and, move for example the curves of one channel, and now, with that initial coloration, you can now use that tool.
To avoid the hairs, try using Color>Decompose and use HSV.
Now you can use that channel as a start for a mask.
Technically, white isn't a colour, and so you can't really rotate the colours in a white t-shirt. Also you are going to need to use layer masking here if you want to target specific areas.
I would separate out the parts I want to colourise using layers and layer masks. That is having the background separate from the t-shirt, and separate from the head and arms, and so on. I'm sorry but there are no real shortcuts here. To get a good mask for a human subject with hair, you can use the Foreground Select tool in GIMP. There are tutorials on youtube on how to use this, and an answer I gave here which might help. You don't have to select individual hairs. This tool will do that for you. For other parts, using the Pen Tool is probably easier.
In the example below, I am using the Colors > Colorize filter to change the colour of a white t-shirt which I have masked on its own layer. The background layer contains lots of colours, and you could use the Hue-Saturation filter to rotate the colours on that layer.
And here is an example rotating the colours using a Colors > Hue-Saturation adjustment on the background layer only. Note that the animated GIF colours in my screen capture are not smooth. The real colours on screen are much better.
