The article on microencapsulation brought back many pleasant memories (C&EN, May 14, page 15). My first employer was National Cash Register Co., where research involved microcapsules made of gelatin using coacervation (phase separation). I recently viewed a 13-minute motion picture I made in 1960 with a Bolex 16-mm movie camera. The movie was entitled "Microencapsulation—A New Research Tool," and it employed time-lapse photomicroscopy, amateurish (by today's standards) animation without the advantage of computers, and live action. Actors included chemists Joseph Scarpelli, Marjorie Lyon, and Herbert Ezekiel (as narrator), among others.
The short film showed the process of making capsules (from a few micrometers in diameter up to a centimeter), testing them, coating paper, and (to us) wondrous things that could be accomplished with the finished product. Potential uses were predicted: timed-release drugs, photochromic self-adjusting sunglasses, rapid light intensity control with encapsulated magnetic particles, instant color changes of encapsulated dyes using the proper wavelengths of light, and (of course) carbonless carbon paper (called NCR paper–No Carbon Required). And, after all these years, I still have a tiny vial of those capsules.
What a marvelous way to launch a 50-year career in science!
Donald A Burns
Los Alamos, N.M.