The multiplier phototube thickness indicator developed in this research detects the varying thickness of the carbon ink coating on a moving web of paper. The absolute effect of the density variations of any of the particular types of tissue tested on those measurements has not been fully determined as yet, but it is believed that if a given type of tissue is used the density of variations of the paper can be neglected or compensated for. Changing the type of tissue when coating would necessitate recalibration of the multiplier phototube thickness indicator every time a different type of tissue was used.

The multiplier phototube detects changes in density in a moving web of paper. This property can be useful in monitoring the thickness of tissue paper as it is being manufactured and in monitoring and compensating for changes to the density of different types of tissue fed into the ink coating machine.