This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
Most show cases have mirrors at the back, either in the form of sliding panels or spring doors. Lettering in distemper colors on these mirrors can easily be read through the fronts or tops of cases. If the mirror is on a sliding panel, it will be necessary to detach it from the case in order to letter it. When the mirror is on a spring door the sign can be lettered with less trouble.
By tracing letters in chalk on the outside of the glass, and then painting them on the inside, attractive signs can be produced on all show cases; but painting letters on the inside of a show case glass is more or less difficult, and it is not advisable to attempt it in very shallow cases.