Be sure your boiling alcohol set-up is in a well ventilated area. When hydrating your leaf following alcohol bleaching, gently apply water to the leaf and avoid potential splitting or breaking due to its brittle condition. Check each set-up to make sure the slide image is in focus or a poor starch picture will result. When executing this lab, safety precautions involving boiling alcohol should be strictly followed. This includes a minimum of six slide projectors.
Much time is spent in positioning and focusing the image on the glass enclosed leaf.
This is unavoidable and necessary. If using a block or modular schedule, you may want to set up and develop the starch pictures during the same 90 minute class period. In ordinary photography, a print is obtained by illuminating a piece of photographic paper through a negative. A chemical reaction occurs where the paper is illuminated, and fine grains are deposited. A starch picture is made similarly.