This week I got called by a buddy of mine that owns a shop in town. He has a 67-72 style custom painted truck in the shop. They were doing some touch up work and couldn't get the color to match. They had already spent 2 days on the color.
I went down to see what was going on and found this.
The color appears to be a pastel peach type varient. This color when you spray your base color, lays down fine, covers in 3-4 coats. Sounds normal right.
You can get a very close match holding the freshly spayed test panel to the vehicle. Now let it flash for ten minutes and you've got a color 10 shades darker

. Ok had that's happened before. The strange part is this. You apply clear over that color as it was and it becomes lighter again, but no longer matches as the wet basecoat did.
The shop was trying to tint it as best they could but to no avail.
I asked what they were using to tint with, and gave it a go. Got the color so it was close and didn't change much from the wet base look, to the flashed base, to the cleared color. Problem was the tints they were using kept it muddy looking.
I finally told him to just go get me the corrrect tints that were supposed to be in this color, no substitutes. I started with base white and added the tints as my eyes saw it needed reguardless of what the actual formula wanted. (colors in the formula were: white, transparent orange, Yellow oxide, black and clear)
With in two hours I had him a near perfect (to my eye) sprayable panel match. The customer only wanted the hood sprayed, but nothing else. so that was their biggest reason for needing a perfect match
So with that info here is the question for the paint gurus.
In the original formula what would have caused the color to flop from light wet base to dark flashed base then back light again just because it had clear over it (even after the clear was dry)?
I don't recall the exact amounts of each in the original formula, but they were something like this:
White 178 units
Orange 54 units
Yellow 47 units
black 4 units
Clear 278 units