[Captain Bob]

Prior to the turn of the 20th Century almost all black and white photographic negative plates had an orthochromatic emulsion which was only sensitive to blue and green colors. Additionally as much light as possible was used to shorten exposures, but caused the pupils of the subjects eyes to be closed down and small. A particular result was that portraits of people with especially bright or strong blue or green eyes would end up with strange unnatural looking all white eyes when prints were made from these negatives. The usual correction for this was “spotting” of the negative or print using primarily soft graphite pencils or special spotting paints applied with ultra fine brushes - obviously some photographers or their assistants were more skillful at this than others. This problem gradually went away after the turn of the century with the introduction of panchromatic films which were sensitive to all colors and faster as well.