What is the best method for applying the emulsion to the plate, and how many layers of emulsion are ideal?
Room Temperature: 72 Degrees Fahrenheit
Researchers: Mady Lacaprucia and McKenzie Stuetzel
Test A. For our first plate, we decided to try to use a foam roller to apply the emulsion. We followed the procedure that is detailed below.
- Cut the plate to desired size.
- Degrease with Bon Ami.
- Pull mesh taught in embroidery hoop.
- Mix acrylic paint and water together, approximately 60% acrylic to 40% water, in small container.
- Layer a small additional piece of PETG (not the plate), then newsprint, next the PETG plate, then finally the embroidery hoop on top. The first piece of PETG plate was used to raise the actual plate closer to the mesh on the hoop.
- Apply diluted paint to the mesh over the plate using a paint brush in a thin layer.
- Use mat board to smooth the layer of paint.
- Let dry; it took approximately an hour and 30 minutes to air dry. A hair dryer will speed up the process.
- Carefully flip embroidery hoop over and cut around the plate, leaving a small border of mesh around the edges. It is helpful to start with an X-Acto knife and finish with scissors.
Application of Emulsion:
- In dark room, we applied one layer of MacDermid Autotype 6000 emulsion with a foam roller. It was already clear that the roller was not the best tool for application, as the emulsion applied in streaks and we could not get it to apply evenly. We tried to use a piece of mat board to smooth the application.
- We let the emulsion dry next to a fan.
- We then applied a second coat of emulsion, this time using only the mat board. It applied better, but there were still streaks from the first application.
Preparing the Photo Positive:
- The image used on this plate was a photo of an etching of a bridge. It was at a resolution 360 and converted to greyscale.
- Using Curves, the image was adjusted to add more contrast and reduce the tonal range.
- The image was cropped to the size of the plate.
- Next the image was bitmapped using a halftone screen with 75 lpi and a 45 degree angle using the “round” shape.
- We printed the image on a laser printer.
- We then left the print to dry for about 2 hours.
- Next, apply baby oil to the print using hands to make it transparent. Use a clean rag to wipe away excess oil.
Exposing the Plate:
- Place the positive (the oiled paper photo) on the exposure unit with the image side facing up, and place the plate on top with the coated mesh facing down. (Emulsion to emulsion.)
- Set the time on the unit – 5 minutes.
Wash the plate with warm water and use fingers to help remove emulsion from the plate. The areas that need to be removed feel a little gummier than the emulsion that will stay on the plate.
Let the plate cure overnight. Then, spray a light layer of Shellac from about 9 inches away from the plate to prevent emulsion from breaking off the plate. We let it dry for about ten minutes. Then, trim plate to desired size to remove excess mesh.
Printing the Plate
We printed this plate on the Praga etching press with a sizing catcher and pusher blanket with medium pressure. The paper we used was Hahnemuhle Copperplate white, which was soaked for about 15 minutes and blotted dry with a towel. We used Gamblin Bone Black ink, mixed with 00 burnt plate oil, and wiped the plate with a tarlatan like an intaglio plate. When printed, we found that the streaks created by rolling the emulsion onto the plate were visible as different grey tones.
We found that the more the plate was printed, the more the edges of the mesh would fray. After making 3 prints of this plate, the frayed edges did not show in the print; however, with continued printing, we suspect that this problem would only become worse. We also decided that using a foam roller to apply the emulsion was definitely not a good technique, as it left very noticeable streaks in the print.