Aquatint

Aquatint allows for tonality to be achieved with the etching process. Tiny droplets of an acid resistant material, typically rosin or spray paint, are applied to a plate. The plate is submerged in acid which bites around the unprotected portions creating small pits, similar to stippling or a dot pattern. This can achieve a wide range tonal qualities when printed. The longer the etching time, the darker the achieved tone.

Process

  1. Thoroughly clean and degrease the plate.
  2. Check that the hotplate next to the rosin box is turned on and set to ~300℉ (The rosin begins to melt at 235℉, but hotplate thermostats may not be accurate.)
  3. Crank the rosin box fan for a couple of minutes.
  4. Wait a moment to allow the larger particles to settle out of the air. Larger particles, when melted, can effectively act as a dot of stop out.
  5. Place your plate on to a support at least a few inches larger then the plate itself. This helps keep internal air currents from disturbing rosin around the edges of the plate.
  6. Quickly open the rosin box and place the plate and support onto the rack, centering it inside as possible.
  7. The longer the plate is inside the rosin box, the more rosin will settle on the plate. I would recommend ~10 minutes.
  8. Remove the plate and without disturbing the dusting place it on the hot plate.
  9. Watch for the color change, from light yellow to almost clear, indicating the rosin has melted and bonded to the plate. Remove the plate promptly when this change occurs. If you overcook the rosin, it will spread out effectively shellacking the entire surface of the plate. If the rosin is not melted enough, it tends to fall off the plate during the etching process.
  10. Allow the plate to cool before applying any ground or placing in the etching bath.
  11. Stop out as needed before etching.
  12. Once you have etched the plate, continue to stop out areas and stage additional bites. Typically stop outs are performed in doubled times. For example 15sec, 30sec, 1min…
  13. When etching is completed, wash off the rosin using denatured alcohol, then clean any remaining stop-out or ground before proofing.