Using a Test Negative
Printer control follows broadly similar principles to process control except only one step is required to be plotted.
A typical printer control strip consists of a single picture frame with a patch of density reading about 0.8.
Several commercially available exposed and processed camera negative rolls are available for colour, but laboratories make their own standard negative on black and white. Some laboratories concerned with film production [rather than archive film restoration] not only make their own standard negative, but also cut a few frames of them into the leader of every negative roll to use them as a standard that is permanently present at every printing.
This practice became common throughout the world from the early 1960's and may one day be an important method for archives to identify the source of the film. The laboratories name is almost always present and the style of the picture that is usually part of the frame is often unique to a period.
