Lubricating jelly helps improve image clarity of inclusions entombed in amber and copal

Abstract

While photographing fossils entombed in amber and copal, I began using lubricating jelly on the specimens as a temporary “mounting” medium to cover the area of photographic interest. Copal is partially polymerized resin (Santiago-Blay & Lambert 2007). Th e product I purchased (using personal funds, approximately USD 4.50 in a local supermarket chain, price for these products ranges approximately from USD 3–14) is described as an “alcohol-free” ... “clear” ... “greaseless, water-soluble, non-irritating lubricant for general needs”. Th ese products are commonly used in medical procedures and for sexual activities. Once the jelly is carefully placed on the specimen, minimizing the presence of air bubbles, a clean cover slip is placed gently on top of the jelly blob. Th e refractive index of amber or copal matches that of the jelly thus reducing scratches and lensing eff ects of rounded pieces. Th e improvement on image clarity is often obvious (Figs. 1–2). Removal of the jelly from the specimen is easily accomplished with lukewarm water and a towel. Lubricating jelly, a non-sterile product, has “chlorhexinidine, gluconate and methylparaben as preservatives, in a vehicle containing glucono delta lactone, glycerin, hydroxyethylcellulose, sodium hydroxide, and purifi ed water” and did not appear to damage the specimens. Th e jelly’s greater viscosity than that of glycerin, a compound commonly used to improve imaging, increases the possibilities of good imaging, particularly when specimens are located in areas diffi cult to photograph. Amongst several high viscosity translucent materials I used during the summer 2007 to improve image clarity, lubricating jelly performed the best. Acknowlegments. I thank Scott Whittaker (Electron Microscope Laboratory, Natural Museum of Natural History Washington, District of Columbia 20560 USA) for numerous discussions on improving the photographic quality of biological inclusions in amber and copal. Anonymous reviewers off ered suggestions to this manuscript. I am grateful to several colleagues who tested this method successfully for research and did not consider this subject matter “too personal”.