Steel plates for intaglio printmaking have several advantages over copper or zinc plates:
- unlike zinc, steel does not oxidise the inks so colours stay pure;
- the metal is less expensive;
- it is tougher, less prone to wearing out during editioning and capable of larger editions;
- steel has a natural scope for fabulous mark-making. Open-bite areas may not need an additional aquatint to achieve strong blacks;
Steel also has a number of downsides:
- the plates are not as highly polished as zinc, so work is needed to polish them if you want to achieve white areas in the print on any un-etched areas of the plate;
- steel is tough, so prepare to bounce your weight on the guillotine to cut new plates;
- they will rust, so stores them in a dry, warm place and for long term storage oil them and wrap them in grease proof paper or plastic;
- steel plates usually come un-backed, so you will need to back new plates with tape, straw hat varnish or spray-on car paint;
- you cannot use the same acid for steel as for zinc or copper, so you will need to mix a fresh tray and keep it separate.
Preparing steel plates
- First, I recommend making test plates with any new technique. So cut a couple of small strips of steel plate, back them with brown packing tape, straw hat varnish or spray it with car paint and trial different resists over different times.
- A 1:4 acid solution is typically used for steel, but I made a mistake and started with a 1:2 solution for my test strips. Steel takes longer to etch than zinc. I used a hard ground resist and drew lines into it with a needle and with 1:2 acid I achieved a beautiful sharp line after five minutes. I feathered it constantly during this time. The line was darker but still controlled at 10 and 15 minutes but started to deteriorate at 30 minutes. For a deep open bite to achieve embossed texture you can expect to leave the plate in the acid for more than 40 minutes at a solution of 1:4. Do take the time to prepare your own test plates before you start your actual plate because many factors will affect exposure timings – room temperature, age of acid, quality of steel, feathering and other factors – so don’t rely solely on the times I have suggested.
- When you’ve got the test plate results prepare your main plate, start by backing your plate (as in 1).
- File the edges and corners as usual to protect the press/blankets and enhance the final print. I use a wooden handled cross-grain file and then a hollow scraper or burnisher. Some people finish with an Arkansas stone to achieve a smooth finish that is easily wiped.
- At some point in the process if you want white areas on your final print you’re going to have to polish the steel. This principally applies to black and white etchings, it matters less if you use colour. Some people do this at the beginning when it’s easy to polish without any risk of damaging the image. Start with fine wet and dry sandpaper, then move on to Brasso and work with the grain of the steel. Aim for a high shine and test progress intermittently with black ink to see if the plate still has fine marks which will hold ink. Other printmakers treat the natural light grey which the unpolished steel plate will give you as a mid-tone, so they etch the plate first then polish back only those areas they want as highlight tones. To do this use a small burnishing tool which can be readily controlled.
- All the familiar etching resist methods work with steel – hard ground, soft ground, sugar lift, photoetching, stop out… so prepare your plate as you would for zinc at this stage.
- I put a loop of brown tape on the back of my plates to make them easy to remove from the acid. You can see this protruding above the plate on the photo above.
- When you put the plate in its own acid bath use protective eyewear, chemical resist gloves, extraction and have a tray of water adjacent ready to wash out the acid. Don’t cut corners on this.
- Steel in acid produces clouds of black and exposed areas will bubble away, so prepare to stand over it and feather fine lines.
- Don’t be afraid to take the plate out of the acid, rinse and dry it and check it with a magnifying glass to check progress. You can always put it back in for longer. Designs with a lot of close lines are likely to degrade the plate quickly so watch it carefully.
- When the plate is ready, rinse, dry and print it as usual.
- For short periods of time the plate will be fine stored in a dry place, but for longer term storage oil it and wrap it in grease proof paper/plastic to prevent it rusting (and still avoid leaving it in damp basements/sheds!).