I was commissioned to make a 6×8″ copper plate of Tommy the cat. After some back and forth with the client, we chose a photo and I got started.
The client provided me both with the original photo taken and one that she had adjusted to get better details in the face, which was a bit in shadow. In the end I used the adjusted photo to create the design in Inkscape. Next, I made the design monochrome to import into the cutting machine software, then cleaned-up, removed, and added a few cut lines in that program to cut out the final stencil in vinyl.
I had a 6×8″ blank on-hand, but I’ll summarize the steps to make them: rough-sand the mating surfaces of copper sheet and plywood; laminate them together using contact cement; cut blanks to size; file down sharp edges; final sand up to 220 grit. With the stencil cut and blank ready, I transfer the stencil to the copper surface.
Now to apply the colours. I weed-out the spots in the stencil to expose the copper that will get painted black. There is not much black in this design and I have found that it’s easier to work with an unpainted stencil, so I mask-off as much as the stencil as possible before painting. I find it saves me time and eye strain down the road, when I need to weed other colour layers, ha.
After a couple days of the paint curing, it’s ready to add another colour. I next weed the background, apply chemicals, and seal in the container to react. 6-8 hours later, I remove the plate and let dry in the air for a few hours more to “fix” the blue. I find the blue washes away more readily if I rinse when it’s still wet. I clear coat the plate before moving to the next colour.
Next is the dark brown. I weed the stencil, apply chemicals, let react, rinse, dry, and seal with clear coat. You need to babysit the brown colour reaction a bit – depending on the shade of brown and conditions in the reaction chamber, it could be a couple minutes, or a couple hours to wait. I repeat the same steps for the lighter brown colour.
I attempt to get an orange kind of colour for the next layer. I let this reaction occur in air, and I apply the chemicals, let sit, rinse, and repeat a few times in a row before the final rinse and dry. Before sealing, I remove all the “white” parts of the image, which will remain the shiny bare copper.
All that is left is the nose, which I try to colour pink. I apply the chems to make it dark brown, and let it sit in the chamber. Afterwards, I remove it, apply an acid to brighten the brown to pink and rinse profusely with water before drying and sealing.
In the end, I was happy with how the copper portrait turned out, and the client was pleased, too. There will always be random variables, but I am getting better at predicting an upper time limit to get a specific shade of brown. I still stay close by and regularly check on the progress while it’s reacting so as not to go too dark. If it does go too dark, worst case, I could brighten it, reapply chemicals, and try again, to some extent, but try to avoid that when I can.