Once the drawing is done, I prepare the copper plates for a transfer. To polish the plates, this time I borrowed a fellow printmaker's orbital sander which he had outfitted with an old piece of printing felt instead of sandpaper to which I applied jewellers' rouge and oil for a final polish. It worked like a charm and saved a ton of time on those two large plates (I need to get one of my own!!!). After the polishing, a hard ground (asphaltum) is evenly and thinly brushed onto the surface of the plate. This brownish-black and shiny coating will protect the copper in the acid. Transferring the pencil drawing is really easy at this point. Once the asphaltum is dry, I simply run the plate with the drawing through the printing press and the graphite transfers beautifully onto the black surface without smudging. In late September I started needling the plate, meaning that I draw the whole image with a steel needle (I also like to use my burnisher for thicker, bolder lines) through the asphaltum layer. Where the copper is exposed, the acid will bite and therefore create my line etch. In this close-up of my plate you can see part of the graphite transfer and part of the already needled lines.
Once the plate is etched, I strip the asphaltum from the surface. Left are all the etched lines in the plate, which I then fill with a special printing ink, polish the surface of the plate clean and run it through the press with a sheet of damp paper overtop. Voilá! I have the first proof of my line etch (click on image to enlarge).
Since My Minneapolis will be a colour print, I need a second plate which will hold the colour. My first plate, the key plate, will hold all the black lines and any grey-black tones or aquatints (more about that later). For the colour plate to line up with my key plate, I need to use a good registration system (more about that also later) that will ensure that both plates will always overlap properly and 'match up' correctly. For this to work, I transfer the key image onto my second plate. As soon as I pull the first proof, I exchange the just printed plate on the press bed with my second plate that is coated with the asphaltum. I then run the still damp paper with the fresh print through the press again on top of my second and blank plate. The wet ink offsets onto the plate and I can start needling the lines on plate two which will be my guides for where I want all my colour areas to go. The offset black ink is clearly visible on the asphaltum as you can see in the detail below. Now I have to draw (parts of) the image for a third time. Usually I etch the lines on the colour plate really lightly simply to be guides for the colour aquatints later.