This plotter was constructed and built by the artist Wolfgang Zach in 1987. He is using the machine up to date.
To tell more about Wolfgang Zach the Computer and his Plotter …
Zach has been using computers for creating his works since 1983.
At this time there was no personal computer availlable which could supported his artistic ambitions. For this reason the artist programming his own software under a DOS System, but also designing the hardware himself: he has built his own computer as well as his own plotter.
Zach does not utilize computers and plotters in order to reflect on art and the artist, but rather on the specific process of drawing as well as the act of drawing. So for him the drawing is an independent medium, which he described frequently as as »setting a sign«. He is interested in finding themes where the result of pencil on paper which he use, provides more than what is possible with other methods. The computer allowes him to show new paths for the traditional medium of drawing. He rethinks the attendant conditions of hand drawing and optimizes them by machine.
The basis of his gray-shaded pictures is a complicated process comprising a number of technical steps. He has calibrated the drawing process to a particular paper ((lightproof and acid-free) ) and always use the same leads. The images are drawn by a graphite lead in various hardness grades which range from 2H to 4B. By using leads of eight different grades it can achieve a very broad range of gray scale values. Of the possible 256 gray values, he can print 200 and will certaintly reach 256 gray scales in time. It is guided by a drawing device, or plotter.
Zach works with two types of plotters:
Beside his selfmade plotter, Zach uses a conventional industrial plotter.
The industrial plotter, such as those used by architects, he uses for small-format drawings.
The self-made plotter is used for large-format drawings he has produced since 1987.
(width: 157 cm; length: infinite)
»This plotter functions in the manner of a drawing table across which a track-guided carriage passes over the flat paper parallel to two edges of the table« (p.14). The carriage contains a »drawing head« which moves through a stepping motor a graphite lead line by line, from left to the right, over the paper.
The plotter is controlled by a computer program which was written by Zach himself under a DOS System: in the beginning for each specific source image; later as a universal program.
The basic core of the program comprises data by means of which it is possible to match the scan lines of the original photo with the line width in the drawing.
A further core of the program is the conversion of color values in grey values through a formula ((red + green + blue):3). Sometimes the greyscale is editing in advance. The program adjust the drawing head to the right graphite lead which fits to the inquired gray value.
There the machine have to consider all attributes of the graphite pencil: The machine must determine the abrasion of the pencil, to regular the press of the lead and readjust the lead automatically, resp. to stop if the lead doesn’t sustain the press or break off.
The plotter needs about one week to complete a large-format drawing.
For this the plotter »allows the processing of paper having a width of up to 157 cm and theoretically of infinite length, for Zach has designed this plotter in such a way that it can write slowly on long reels of paper across the drawing table.«(p.14).
Die fremde Hand 2008 (The Foreign Hand), p. 11, 14-18, 20, 23, 25
Susanne Grabowski: Talk with Wolfgang Zach at January 29, 2009 in his atelier in Bremen (Germany).
