Firstly, Indiana Jones and the Kingdom of the Crystal Skull is a terrible title; for the same (mediocre) movie, Indiana Jones and the Secret of Akator would have been leagues better. This post, however, examines KOTCS through the lens of its visual palette. It was inspired by a particularly astute quote from one JacksonArcher on the message board TrekBBS.com:
What I liked most about Raiders of the Lost Ark was that rough-around-the-edges, gritty type of sensibility that has gradually dissolved throughout the series.... Plus, I think a big factor in separation from the rugged quality of Raiders to the quality of Crystal Skull was that everything seemed too polished and neat. The cinematography was way too polished and clean for an Indiana Jones movie. Even the locations and sets and special effects had this very pristine quality that felt totally out-of-place.
This is an excellent and, to my mind, decisive point. Let's compare some college shots from Raiders... (click all pictures to enlarge)
to some college shots from Skull:
Here's Indy's house in Crusade:
A creepy place from Raiders (note how both Indy and Satipo are in the frame, albeit barely visible in the realistically underlit temple):
Crusade (the set design being already too fancy and showy, IMO, but at least the lighting and color palette fits):
I agree with JacksonArcher. Storybook/painterly color can be used to great effect in outright fantasy (LotR, Harry Potter 3 and 4), contemporary comic book fantasies (Iron Man, Dark Knight), or even drama (The Good Shepherd covers periods close to Skull's, and with a similarly dreamy look). But the downside to the perfect lighting, super-high contrasts and general prettiness is a creeping sense of unreality. This may not be a big deal for Frodo, Tony Stark or even Casino Royale's Bond, who all live in fantastical, glamorous worlds, but when Indy and his series' defining characteristic is gritty, sweaty authenticity, painterly visuals and the character are badly at odds.
Heck, take a gander at 2001's The Mummy Returns:
Its visual palette is closer to Raiders than Skull's is!
Ultimately, KOTCS's color scheme reveals the movie's core nature as the work of a trio of old softies waxing nostalgically about the era they spent their childhoods in and having a bright, cheerful time doing so, all the while making themselves and their surroundings as pleasant and good-looking as possible, to the extent that the outlines of their heads often seem framed by halos of divine light: