Picture Tube Spot Analysis Using Direct Photography

An exact description of the characteristics of a picture tube spot at the screen of the tube -its size and shape as current level varies and its core/haze ratio as focus varies -is not readily obtained using most available analytical techniques. For instance, scanning slits or probes that are often used for this purpose fail to faithfully reproduce the lack of symmetry that may exist in a CRT electron beam; further, the results produced are time consuming to interpret and can be misleading.