Gibson: “Dr. Allison Jack and Family”
Dr. Allison Jack and Family
Media: Modern Tintype (Aluminotype)
Dr. Allison Jack and Family is a one of a kind image shot in the style of the tintype of the 1800’s. The procedure and chemistry is essentially the same wet plate collodion process from that time but the substrate is aluminum sheet coated with a black surface on one side and currently used commercially in trophy labels. The original plates were never tin, but thin iron sheets that had been ‘japanned’ with a black lacquer.
The plate, whether blackened metal or glass, is coated with a solution of ether, ethyl alcohol, gun cotton and salts of bromide and iodide. The ether and alcohol quickly evaporate leaving a moist but firm coating. This is then submerged in a 7% solution of silver nitrate for 3 minutes during which time, the bromide and iodide salts attract the silver nitrate thus making the plate light sensitive. The plate is then placed in a holder under safelight conditions to be carried to the camera and exposed. The sensitivity of the plate is quite low (~ ISO 0.2) requiring an exposure in the 3 to 30 second range depending on the light available and the f/stop opening used. The plate must then be developed in a darkroom before it dries, hence the ‘wet-plate’ collodion name. I have adapted the back of my van to be a darkroom and used it in the processing of this portrait while on location in Colorado this August.