Summary Color print with transparent middle layer. First option: one file with three color layers first: black 0.6 mm (starts at 0 mm) second: transparent 0.6 (starts at 0.8 mm) third: black 0.6( starts at 1.4 mm) Second option: to make a pair of earrings print: four times in black : wingTopAndBottom_make2.stl two times in transparent : wingMiddleTransparent_makeOne.stl glue them together in the following order: black, transparent, black.