This Recommendation deals with electronic tubes which perform the function of converting an optical image into electrical signals. These tubes are commonly called "television camera tubes" or "television pick-up tubes". At the present time, they fall into two classes: a) tubes having a photoemitting sensitive surface; b) tubes having a photoconductive sensitive surface. This Recommendation deals only with the image orthicon in class a) and with the vidicon in class b). Other tubes and/or classes may be added as the need arises.