I don't claim to be a paint expert but here are a few things I have seen
that can cause the differences in colors that you mention.
1. The paint on the car has faded due to exposure to the elements.
2. The paints from different cans (you mentioned remainder of one can)
may be slightly different, especially when mixed in small amounts.
Because of this, you should always mix all cans that you intend to
use on one vehicle.
3. The paint may not have been uniformly mixed either when originally
applied or at touch-up time.
4. The appearance of some paints (mainly metallics) is seriously affected
by application techniques such as air pressure, paint volume, distance
from the spray gun to the painted surface and even direction of
application (right to left, top to bottom, etc.)
The moral of the story: When touching up paint, always paint entire panels
or paint all the way to a break in the surface if possible.
> From email@example.com Mon Apr 15 14:27:59 1996
> Date: 15 Apr 96 14:50:03 EDT
> From: Rick Huber <102221.1716@CompuServe.COM>
> To: mgs <firstname.lastname@example.org>
> Subject: Best BRG colors
> Sender: email@example.com
> Reply-To: Rick Huber <102221.1716@CompuServe.COM>
> Content-Length: 533
> Answering Don Mathis' question about the best BRG's, I repainted my 68 B the
> original factory code GN25, medium dark green, which is my favorite BRG. I
> don't remember which brand of paint we used, but it was one of the ones in the
> Moss catalog matching the factory color. One thing that's unusual about the
> color is that when I used the remainder of one can of paint for touching up a
> couple of dings, the touch up paint was much darker than the finish of the
> Anyone know the reason for that ?
> Rick Huber
> '68 B Daily Driver