Toronto. Nearly a half century ago, I modified my Heathkit Mitchell Fotoval enlarger light meter with a built-in timer that used a 555 chip, a tantalum capacitor, and a series of switches and resistors that set the enlarger timing in ever doubling steps – 1, 2, 4, 8, 16, … seconds realizing that you had to double exposure time for the equivalent to a one stop increase in light. I changed my Gralab darkroom timer to add a fuse, relay, and a foot switch outlet plug.
When colour printing came a long, I built an enlarger bench with a built in iron vane (true RMS) AC meter and a variac transformer so I could adjust for vagaries in Montreal’s somewhat erratic power system of the day (pre Hydro Quebec). Continue reading

















