Is there a difference in primer colors?

[partonkevin]

I was just looking at primers for a small painting project. I saw the gray, red oxide, and a yellow buff primer. I've always used the gray, but is there a difference in the primers? Are there guidelines to go by? I once heard that paint doesn't stick well to the red oxide, so that's why I've always used the gray. Any comments?

[Kubel Nick]

I heard red oxide is better, but in reality it's not the color but the manufacturer of the paint is what really matters. Everything else is just color choice to me. Using different color is good for block sanding to see high/low spots. Worry about the brand, not the color for rust protection IMO.

[buguy]

Only real differance is the color that will be under your color coat. Different primer colors change the hue of the color coat.