Star Wars Episode 5: The Empire Strikes Back - Is R2-D2 Black?
During any scene where R2-D2 is in space, blue screening messes things up. Blue screening makes any thing in blue take a different color. R2-D2's once blueness has changed to black because of the blackness of space.
Actualy no, it was never fixed in the specail edition and r2d2 is still black. They should have fixed it and they should have fixed the rancor because he still has the black mat lines around him and the screen of the rancor which looks hella fake!
This is a process known as 'chromakey' and seeing as it wasn't as advanced back in 1980 as it is today they ran into the problem of R2's blue insignia turning up black in space.
Chromakey is the process of replacing a nominated color (commonly blue or green) with a picture, image, video, or matte of your choosing. Because they were using this technology to apply the black matte of space infront of a blue screen, R2's blue insignia picked up the black matte also. Ideally they should have shot the R2 space exteriors infront of a greenscreen to eliminate the error, but oh well!