Why do those early Disney animated films have that certain "look" to them?

[Steelmaker]

After watching Snow White, Pinocchio, Fantasia, and Bambi I have noticed something with all of these EARLY early Disney films, probably up to Cinderella. The inking (or painting, coloring, whatever the technical term) seems to always have a more fuzzy, grainy, "faded" color pallette when compared to other Disney films, probably starting with Alice in Wonderland which suddenly has a much richer, brighter color pallete and sharper. All Disney films from Alice going forward has this change in coloring. My question is, why did this happen? Was it an artistic decision? Did the tools and techniques suddenly get better? Or is it that the original source of these older films became so deteriorated, that even with painstaking remastering they were unable to FULLY recapture what these older films originally looked like?