|Welcome to Sprocket School! This project is maintained by volunteer editors. A guide to editing.|
The discussion of orientation is incorrect. For positive prints, A-wind vs. B-wind refers to whether the emulsion faces the lamphouse during projection. A-wind is the typical orientation with the emulsion facing the lamp, while B-wind would be reversal film where the emulsion faces the lens.
For 35mm projection, SMPTE RP 39 calls for winding emulsion-in at all times for 35mm release prints. Some projectionists don't agree with this standard because the testing was done with triacetate and was not repeated with polyester, but the same projectionists often don't wind triacetate emulsion-in, and emulsion-in remains the SMPTE recommended practice for all bases.
Some projectors (ex., many with enclosed magazines) cannot safely run film heads-out emulsion-in, although in some cases an extra roller can be installed to allow safe emulsion-in winds. See page 8 in the 1975 edition of the Century SA manual: