Lev Manovich states that when we categorize a screen into "classical", "dynamic", "real time" and "interactive", what is displayed on a "real time" screen is not an image in the traditional sense, since the image displayed on the cathode-ray tube (CRT), the first real time screen, is constantly and continually updated at a sufficient speed. Here, Manovich clarifies the transformation in the nature of the "image" that we see. However, it is likely that this points to another important change. It means that light which makes it possible for us to see the "image" is changing. Since the CRT, we have been able to control electrical light freely and we have continued to look at it. That is different to looking at light reflected from the conventional environment and it means that we are looking at the light source created by electricity. In other words, the change in the nature of what we see is likely to be deeply related to the fact that we have been able to see the light source itself. Moreover, this change in light is believed to have drastically changed even the nature ofÂ behaviors including our interaction, i.e. drawing, with the environment which mankind has been carrying out since ancient times.
In this discussion, we will first present the specific qualities of the first computer graphics system, Ivan Sutherland's "Sketchpad" because it gave us the original experience of drawing with the computer. Secondly, we will refer to G. Berkeley and J. J. Gibson's theory of vision and G. Seurat's paintings in order to define what the radiant surface of the CRT is showing us. Finally, this presentation will show Sketchpad was the first system which reset the senses ration of vision and touch in our drawing act by controlling the electrical light source.