Schroeder, Manfred R. (1968) 1969. Images from computers. In: IEEE Spectrum. [unknown address]:[unknown publisher]

Abstract:
‘Modern digital computers, in conjunction with microfilm plotters, are capable of generating a wide variety of images. Beyond the mere plotting of curves, graphs, and labels, special programming techniques can produce halftone renditions of pictorial material with wide applications in optical signal processing and data portrayal. Other possibilities include the composition of images from alphanumeric characters, the generation of moiré patterns, and the encryption of images with subsequent recovery by optical means using computer-generated ’keys’. More sophisticated techniques allow the combining in a single optical display of different kinds of information in hitherto unforeseen ways.’ [IEEE, 2011]

‘Digital computers are widely used for the processing of information and data of all kinds, including the pictorial information contained in photographs and other graphical representations. Efficient conversion facilities for putting graphical information into the computer and retrieving it in graphical form are therefore much needed. One of the most commonly employed devices for obtaining permanent graphical output from digital computers is the microfilm plotter. Regrettably, present models have no provision for producing images with a continuous gray scale or “halftones.” In this note several programming techniques are described for obtaining halftone pictures from a microfilm plotter under the control of a digital computer. Illustrative examples of several methods are given.’ [ACM, 2011]

The article was first published in “bit 2” (1968) on pp. 65-79. It was re-printed under the title “Images from computers and microfilm plotters” in “Communications of the ACM” (Volume 12 Issue 2, Feb. 1969).