Art Articles & Reviews

} Using Positive plates in the waterless process Printmaking Series - Part 18 of 21 By Nik Semenoff The use of photographic techniques has become common amongst printmaking today. The simplest approach is the use of positive plates exposed to positives created photographically or drawn with opaque material. Collaborative printers prefer this method as they do not lose an edition if a color plate fails during printing; another can be burned from the transparency. Early in my research I discovered that any of the commercial plates I encountered could be turned into effective waterless litho plates by replacing the gum etch with silicone. The cost of commercial plates made me look at finding a method of producing my own positive supply and I have been using them for most of my editions. Toray waterless plates are the only one available commercially, but these are too expensive for most printmakers. I suggest that any of the common positive plates can be the best use of this technique. Do not purchase the gum finishing solution as it is not needed; just buy the developer for the brand you get. A good point source of light and a vacuum frame are needed for serious work. I strongly recommend a hole punch and registration pins for accurate registration. While commercial punches are very expensive, one can be made up from paper punches from a stationary store - but that is another article. Follow the exposure recommendations of the manufacturer, giving the plate the full exposure to eliminate any background tint. Make sure your positive artwork transparency has an opaque image; otherwise you cannot get the entire tonal range of the drawing. Develop the plate with a soft pad made of "fun fur" bonded to a piece of wood with contact adhesive. After washing off the plate let it dry and coat it with diluted silicone. The image is washed out with acetone mixed with about 5% brake fluid, which retards rapid evaporation. Printing the edition is the same as for other waterless lithography. An interesting variation on using positive plates is the ability to add a drawing to the developed plate before the silicone is applied. One can combine photographs and drawings in this way. For the many colors and plates that I use in my editions, I could not afford commercial positive plates and so developed a method of making my own with recycled plates and diluted screen emulsion. But this is also another story. One can use negative working plates as well, starting with HC line or halftone negatives. Again only the developer for the plate is used as silicone replaces the gum/asphaltum finishing solution. On some negative plates I encountered, the image would not washout completely, leaving the black developer lacquer; but acetone and retarder removed the silicone from the surface of the image and the plates print perfectly. Using positive and negative plates can make a big difference in the type of image an artist produces. This is another example of printmakers borrowing from the commercial printing industry. ________________________________________________ Copyright © 2004 Nik Semenoff Nik Semenoff Artist-in-residence University of Saskatchewan Visit Nik Semenoff's website at duke.usask.ca/~semenoff/ for more information.