If you convert the footage to ProRes, it's now 10 bit. No, the footage suddenly won't look like it was recorded 4:2:2 10 bit...it'll still be an 8-bit 4:2:0 source. But when you push the colors...you are grading in a 10-bit 4:2:2 space...it won't fall apart as quickly as grading in a 4:2:0 8-bit space will.
Things fall apart sooner if you grade in 8-bit vs 10-bit. You'll be grading in a 10 bit space. HOW? Well, you saw for yourself what happens. I don't know the exact science around it, I'm a user, not a programmer. I just know what happens when you do things.
Shane
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