This will be much hard work to get right.

The effect you're looking for is the 'Color Pass' video effect under 'Image Control'. This filter takes a given colour and desaturates everything outside of a given tolerance of it.

If you can picka great colour for your subject then your job will be over in seconds. However, the chances of that are about zero methinks because you'll have both sklin tones and clothes to worry about.

So I think you'll have to find a way to do it in multiple passes using masks but I'm not sure you'll do that in Premiere pro.

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