The sky is not supposed to be blue, but “greyish”
Color correction discussions are often quite entertaining.
HEY MAN I’M LOOKING OUT MY WINDOW AT THE SKY RIGHT NOW AND THAT SHIT IS BLUE
OK, the sky on Tatooine is not supposed to be blue. The ILM guys specifically talked about it in one of the many 1997 featurettes, and if I remember correctly it’s also mentioned on the Episode 1 DVD bonus features.