The Reflector reports that Book of Mormon translation was done with a sheet in between Harris and Joseph.
"Gold Bible, No. 6," The Reflector (Palmyra, New York) 2, no. 16 (March 19, 1831): 126
Smith and Harris gave out that no mortal save Jo could look upon it and live; and Harris declares, that when he acted as amanuensis, and wrote the translation, as Smith dictated, such was his fear of the Divine displeasure that a screen (sheet) was suspended between the prophet and himself.