The 50c received ample use during the 1950s. I find five major types, of which three are well represented in this selection.
The 1951 paper, the 1L1, is bright white and has a medium RA. This stamp is only found with a distinctive deep orange background.
The 1L2 paper, with large to gigantic RA. This stamp is only found with a distinctive pale red frame and faint background.
The 1L3 paper, similar to the 1L1 paper. This stamp is only found with a distinctive deep yellow background.