Agreed! Light Impressions is a great resource. There are a few photographic processes, however, that have specific requirements regarding the use of buffered/unbuffered interleaving paper. For this reason, I would recommend identifying the specific photographic process for the photographs you would like to interleave to determine the best variety of interleaving.
Generally, “interleaving paper should be made of good quality materials and pass the PAT test. To avoid abrasions and to prevent photographic emulsions from sticking to each other when humidity fluctuates, place a sheet of interleaving between each photograph when stacking. Always stack photographs with the emulsion facing in the same direction, never face to face.”