Toronto. When we hear that phrase today, we think the speaker is flying over-night to the coast to wake up bleary eyed and fuzzy for breakfast thousands of miles from home But that wasn’t always so. In the 1950s, colour film and on camera flash bulbs combined to create a new problem. Even today with the ubiquitous modern smartphone cameras and flashes we somes times see red eye pupils.
In dim light, our pupils expand to let in more light. If light reflects back off our retina, the retina appears to be red. With an on camera flash close to the lens. this reflection makes people in the photograph have red, not the usual black pupils. Professional photographers would use off camera or bounce flash to avoid this issue.
When computers and image correction applications came along, a tool was added to allow the red pupils to be covered by a same size-disk of black with soft edges replicating natural pupils. Modern day smartphones have a sufficiently high ISO ratings that in most cases the flash becomes a fill flash and red eye is avoided. If not, similar edit tools on the smartphone apps usually do the job without recourse to computer-based applications as shown in the above image, courtesy of Skydocu Inc. on its iPhone site.