[chadeast]

Having just (nearly) finished collecting the set, and being a stickler for colors, I'll share my 2c. First off, I suspect that the two cards you have shown are a lot closer in color than those photos would lead you to believe. You can see how much lighter the PSA slab looks in the one with the "lighter" brown background. Even the black on the label in the washed out photo is more of a gray. This is one of the big challenges in buying Goudeys online, variation in scanner settings and/or photos. I've been pleasantly surprised with cards that looked washed out online, and I've been saddened to receive cards that looked like they had great color but were faded when I received them.

That being said, yes, there is a big variation in actual colors as well. This has been perhaps my biggest challenge in collecting the set, getting cards with strong vivid colors. Some cards look factory fresh with amazing color (I love those!), others have some fading that seems reasonable considering their age, and yet others appear to be either badly faded or soaked in some chemical that has bleached out the color. I can't say for sure whether or not these are factory issues, but given the very wide range in colors that I've seen, I believe that most of the variation are due to aging, probably from exposure to sunlight in varying degrees over the last 88 years, and dirtiness or toning or whatever the term is that you care to use. The yellow cards can vary quite a bit, and are tough to find with bright yellow, because they are so susceptible to toning. Here is a photo of five Max Bishops that I happened to end up with. That toning can occur on all of the cards to some degree, but isn't as visible as it is on the yellow, so with other color background often results in dull looking colors.

I added a couple of my nicer cards below, the Combs came from REA and is probably my favorite of all of my 33's as far as background color, it looks even better in person! Happy hunting!

EDIT to add that grading companies seem to not really know what to do about faded colors, so grading is often completely independent of color saturation. The recent discussion about the #144 Ruth PSA 7 in the SCP auction is a great case in point.