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Printmaking with Hard and Soft GroundsJane Humphreys |
For my project, I tested etching, a type of intaglio printmaking, with hard and soft grounds. The purpose of my experiment was to test nitric acid concentrations of two, four and six molar to see which concentration would work best for each ground using zinc plates. I hypothesized that the soft ground would need a lower concentration of acid than the hard ground, because I felt the soft ground would come off the plate more easily. I continued to experiment with each ground, using an appropriate nitric acid concentrations. For the hard ground I used the stylus to remove the ground and for the soft ground I used both the stylus and fabrics to remove the ground. After working with each ground keeping time, concentration, and amount of acid constant while improving ground and ink application techniques, I was able to make a final triptych piece where the scene continues throughout the plates.
Engraving started thousands of years ago in cave art, while making multiples began 3000 years ago by the Sumerians. The Chinese started making prints possibly as long ago as the second century AD. The Japanese began making prints that were authenticated in the late-middle eighth century AD. Europeans were slower to start printmaking with paper, because they started making paper later on than the east. At first, printmaking was used for communicating (worldprintmakers). In fifteenth century, intaglio prints were being made by craftsmen like goldsmiths. Many of the first engravers had worked for goldsmiths (Ross, Ross, Romano 65). By the eighteenth century prints were becoming works or art and in the nineteenth century, prints were signed and printed in limited edition (worldprintmakers).
Although I had done the previous printmaking labs, I still learned a lot from my research. Printmaking can be done in many different ways with different techniques and materials. To understand intaglio printmaking, the purpose of each step must be explained. I chose zinc plates which are the most commonly used. They are backed with an acid resistant material so only the top side will be bitten by the acid. Their main draw back is that they affect certain colors when printed (Leaf 11). Two main chemicals are used for the printmaking process, mineral spirits and isopropyl alcohol. Mineral spirits both clean the plate and remove ground. It follows the rule that like things will dissolve each other. The ground and mineral spirits are non-polar and organic, therefore the ground gets removed. Isopropyl alcohol, also known as rubbing alcohol, is used to clean the plate even more. It follows the solubility rule as well, because it removes the finger prints made by fatty acids on our hands, which like the isopropyl alcohol, is relatively polar (chem&art). Ground is used to coat the surface of the plate, because it is acid resistant, keeping desired parts of the plate unbitten. Hard ground gives an appearance like an exact pen drawing while soft ground gives an appearance like a soft pencil drawing once the plates are printed (Leaf 81). Soft ground can be put in the same acid solution as hard ground, but will bite more slowly, so it is suggested instead to use a more concentrated acid when using soft ground (Leaf 84). The typically used nitric acid which etches the plate is known as the etchant. It oxidizes zinc creating the bubbles that can be seen on the plate. These bubbles are hydrogen gas and must be brushed away, mainly from the hard ground, to keep them from messing up the acid biting the plate (Leaf 116-117). The acid bites down and sideways, so the lines get both deeper and wider (Leaf 115). Once the plates are bitten, they need to be inked. The ink must be mixed with burnt plate oil, a material made from linseed oil, that thins out the ink making it less heavy (answers.com). Before printing, the paper must be dampened, because when soft, the paper can be pushed into the bitten areas of the plate (Leaf 134).
Printmaking is a popular art form that has long been in existence. Knowing the techniques used and the effects of both the hard and soft ground, I decided to experiment with them both.
Materials:
16 zinc plates, lots of paper towels, Putz-Pomade, minerals spirits, isopropyl alcohol, hard ground in beaker with brush (keep covered), soft ground in beaker with brush (keep covered), vaseline, beaker to make homemade soft ground, brush for homemade soft ground, stylus, 6 petri dishes, 6 molar nitric acid, RO water, graduated cylinder , small paint brush (to remove bubbles from plates), tweezers, clock or stopwatch, plastic wrap, ink, burnt plate oil, plate glass, palette knife, small cardboard squares, squares of newspaper, hot plate, 3 textured items ex. fabric, hand roller, computer paper (for template), printing paper, large shallow tub with water, blotters, 2 liter soda bottle filled with water, printing press, pencil, goggles, gloves
With each of the sixteen zinc plates, remove the plastic covering. Put Putz-Pomade
onto a paper towel and scrub the service of each plate till no more black
comes off of it. More Putz-Pomade may be necessary. Put isopropyl alcohol
on each plate and clean with a paper towel before putting ground on every time.
Wear goggles when working with minerals spirits, isopropyl alcohol, and the
nitric acid. Gloves can be worn too if desired.
Part 1: Testing Concentrations
Lay six zinc plates onto dry paper towels. On three put hard ground and on three put soft ground. For the hard ground, do one stroke across the plate applying no extra pressure. For the soft ground do a stroke in each direction across the plate without pressure. Let the hard ground dry for ten to fifteen minutes and the soft ground dry for three to five or until it no longer looks liquid. Draw a circle, an X, and a straight line spaced apart on each plate using a stylus. Get six petri dishes. In two put 30ml of 6 molar nitric acid. In two put 20ml 6 molar nitric acid and 10ml RO water to make 4.5 molar nitric acid. In two put 10ml 6 molar nitric acid and 20ml RO water to make 2 molar nitric acid. Put one plate with hard ground in each 2, 4, and 6 molar nitric acid concentration. Put one plate with soft ground in the remaining 2, 4, and 6 molar nitric acid concentrations. While in the acid, use a brush to remove the bubbles that form on the plates. Leave in acid for four minutes and then remove the plates with tweezers, rinse in cold water, and put on a paper towels.
(Second half of procedure for each part of project) Put mineral spirits on each plate and fully remove the ground. Next clean with isopropyl alcohol. Lay zinc plates on paper towels to ink. Choose a color to ink the plates and mix with burnt plate oil using a palette knife on plate glass. The paint should be sticky. Dip small cardboard squares into into the ink and ink the plate, fully dragging the cardboard in all directions to make sure the bitten areas get fully inked. Remove some excess ink with a clean side of a cardboard square. Lay plates flat and with newspaper squares, evenly blot excess ink off the surface of the plate. Once a good amount of the excess ink has been removed, move the newspaper in a circular direction with your hand flat and evenly, lightly distributing pressure to remove ink. If needed, the zinc plates can be put on a hot plate to make the ink easier to remove. Keep temperature relatively low and watch the plates. They get hot!! Make sure once the surface of the plate is clean that the back and sides of the plate are clean as well.
Next, make a template for printing.
On a sheet of paper outline the size of the printing paper you will be
using and then around the plate(s) where you want them to be located. Plates
can be printed together or individually. Put template on the bottom of the
press and then the inked plates in their outlined positions facing up. The printing
paper must soak in a tub of water fifteen to twenty minutes, then put between blotters. If it is removed
just before printing, place it between blotters and
roll over the top with a two liter soda bottle filled with water. No wetness
should be visible on the surface of the paper. Put the printing paper on top of plates in the outlined
spots. Lay another sheet of regular paper on top to keep the press clean. Put each cloth down slowly in the press, one at a time. Twist lever and
run the paper, plates, and clothes through the press. Carefully lift up each
cloth individually and remove the paper on top of the plates. Let the print dry.
Wash the plates with mineral spirits to remove the ink and clean with isopropyl
alcohol. Label each print once dry. Make sure to keep acid off of your hands,
wear goggles, and when pouring out the petri dishes have cold water running.
Part 2: Hard Ground
Lay three cleaned zinc plates onto paper towels. Brush hard ground onto each
plate and let dry for ten to fifteen minutes. (While drying you can start
preparing your paper and ink. Make sure to put paper between blotters and cover ink with plastic wrap.) Draw into the ground with your stylus, removing
ground from the plate to make your image. Put 20ml nitric acid and 10ml
RO water into three petri dishes. Place each plate into a separate petri
dish. Let the plates sit for four minutes, brushing off the bubbles as they
appear. Remove with tweezers and rinse in cold water. See Part 1 for second
half of the procedure.
Part 3: Soft Ground
Lay three cleaned zinc plates onto paper towels. Brush
soft ground onto each plate and let dry just until it no longer looks liquid.
Using three different textured items, like fabric, place one on top of each
plate. Put an untextured piece of paper on top. Using a mini hand roller,
go over the paper and fabric to press them into the plate. Roll over only
where the the fabric is placed. Once you have gone over it in each direction,
take off the piece of paper and remove the fabric from the plate. Be careful for finger prints. Get three
petri dishes and put 30ml of 6 molar nitric acid into each. Put one plate
into each dish. Carefully brush bubbles that appear, being careful to not
remove the ground. After four minutes remove from acid with tweezers and
rinse with cold water. See Part 1 for second half of the procedure.
Part 4: Both Grounds
Lay one cleaned zinc plate onto paper towel and paint half with soft ground.
Let dry and using a stylus draw into the ground. Cover the other half of
the plate with stopout. Put plate into a petri dish with 30ml of 6 molar
nitric acid. Carefully brush off bubbles as it sits for four minutes and
then remove with tweezers and rinse. Clean plate completely with mineral
spirits and then isopropyl alcohol. Put hard ground on the other half of
the plate. Let dry and then make your image in the ground. Put stopout on
the bitten side and put into a petri dish with 20ml nitric acid and 10ml
RO water. Let sit for four minutes while brushing off the bubbles and then
remove with tweezers and rinse. See Part 1 for second half of the procedure.
Part 5: Final Project
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Using your remaining three cleaned plates, choose which ground to put on each
plate. You can do the plates separately or make a design that unites the
three to print one piece. Use fabric and/or stylus to remove ground for
the plates with soft ground and the stylus for the plates with hard ground. Make your own soft ground by mixing hard ground and vaseline with a 3 to 1
ratio. See procedure in Part 3 for directions on using fabric and soft ground.
Once the images are made place in individual petri dishes in appropriate
30ml acid concentrations. 4 molar for hard ground and 6 molar for soft ground.
Leave in petri dishes for four minutes, brushing away bubbles as needed.
Remove with tweezers and rinse. See Part 2 for second half of procedure.
| Testing Concentrations | Hard Ground | Soft Ground | Both Grounds | Final Project | |
| Ground and Etching | 3 hard, 3 soft Hard ground looked very thick,soft ground was very runny. Soft ground dried too much so etching into it felt like etching into hard ground |
Tryed to use less ground, one exact coat, let fully dry. Easy to etch into and was able to draw exact lines. | Ground was semi-dry, tacky. Fabric placed on top and easily rolled into ground, slightly hard to get fabric off the ground without getting finger prints on the plate | 1/2 the plate was hard ground, 1/2 the plate was soft ground. Drew into soft and hard. Stop out was put onto hard ground side. | Outer 2 plates are done with soft ground, inner plate done with hard ground. Hard to place fabric exactly without finger prints. I rolled over very hard where the fabric was on the soft ground. Hard to use stylus on soft ground, because ground was goopier. Soft ground was made. Hard ground easily etched into. |
| Amount of Solution | 30ml | 30ml | 30ml | 30ml | 30ml |
| Acid Solution | soft 6m, hard 4m | 4m | 6m | 6m (only soft ground acid solution used, because hard ground side etched even with the stopout) | soft-6m, hard 4m |
| Time | 4 minutes | 4 minutes | 4 minutes | 4 minutes | 4 minutes |
Observations While in Acid
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Hard-lots of bubbles, constantly having to brush them away. Soft-less bubbles, had to be gentle brushing the edges, because I didn't want to remove the ground. Hard ground in 6m-constant, big bubbles, 4m-smaller bubbles take longer to return, 2m-very few, small bubbles. Soft ground-very few bubbles in all solutions, some in 4m and 6m. Need to put grounds more carefully on edges | Lots of bubbles around and on plate, constantly brushing and couldn't get all the bubbles to stay away, especially areas like the ears of the animals where lots of ground was removed.
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Not many bubbles. Likely the case, because only very small places had ground removed | Side with soft ground was bitten, but not many bubbles. Hard side didn't appear to be bitten and the red stopout stayed on the plate. | Hard-lots of bubbles, constantly brushing. Soft-still not many bubbles even though both fabric and a stylus were used to remove ground.
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| Color(s) | Van Dyke Brown | Spring Green | Black | Ultramarine | First print-outside plates done with ultramarine and black in a 20 to 1 ratio. Inside plate was inked with vermillion red and deep yellow mixture. Second print-left, more vermillion red added to the mixture with deep yellow from the first print, middle-deep yellow, right-spring green added to ultramarine and and black mixture from first print. (all the ink colors for the second print have some form of yellow in them) |
| Printing Press Setting | 10.75 | 10.75 | 10.75 | 10.75 | 11 |
| Final Appearance of Plate and Print | Lots of ink left on surface, some of the plates have plate marks. Soft 2m-not all lines bitten enough, not right pencil effect. 4m-lines not bitten enough, wrong effect. 6m-looks like pencil lines. Hard 2m-not bitten enough. 4m-good, exact lines. 6m-lines are too deep, dark. | Less ink left on the surface, still some plate marks, lines are smooth, exact, crevices are a good depth, held good amount of ink in them. | Ink removed well from plates. Mesh-darker in some spots than others. String-looks like finger prints (probably partially finger prints and partially the effect of the string), darker in some areas than other. Lace-not rolled over fully enough, on certain parts can see the pattern of the lace though. Looks darker where more ground was removed, so probably from how hard the roller was pressed over each spot. Print looks very much like a pencil sketch. | When ground removed from plate, I realized I should have only drawn one side at a time, because stop out needed to be removed from hard side after the soft ground side was bitten. When I removed both the ground and stop out from the hard ground side, the acid had still bitten through. On the plate there are very faint lines. On the print there is a faint showing of ink from the hard ground side. I removed too much ink from soft ground side and it did not print perfectly. | Plates look properly bitten from the acid. Less plates marks. The ink was properly removed. You can see all of the design on both the plate and the print. Soft ground-both fabric and stylus removed ground and the plates were properly filled with ink after being bitten. Hard ground-crevices have good depth and held the ink well. It is a triptych where the scene continues throughout the plates. The scene continues well even in the middle plate with hard ground, because I used the stylus to recreate the pattern the mesh made in the soft ground plates. |
I found that I originally did choose good times and acid solution concentrations for both grounds in Part 1 of the project. The hard ground in the acid had more hydrogen gas bubbles form, while the soft ground had very few. The chemical half reactions for the zinc is Zn → Zn2+ + 2e-. For the nitric acid, the chemical half reaction is 2H3O+ + NO3- + e-→ 3H2O + NO2. The chemical equation for the etching of these zinc plates with the nitric acid is 4H30+ + 2NO3- + Zn → 6H2O + 2NO2 + Zn2+. This means that when the zinc plate is put into the nitric acid, the NO3- is reduced while the Zn gets oxidized. This reaction is what causes the hydrogen gas bubbles to form on the plate. The hard ground did give more exact straight lines and the soft ground gave the expected pencil like effect. The soft ground could easily be imprinted with texture once I found the correct three to five minute time period for the ground to get more dry. I learned along the way how to clean the ink off the plate, which was the hardest part of the process for me, and found that newspaper and a hot plate were all that I really needed, but that it took time to carefully remove the excess ink . From doing the mixed ground plate, I realized that you can only etch into one side at a time and that stopout does not fully work. After doing this project, I found that printmaking is a timely process with lots of trial and error. My final project shows everything I learned in one piece. By the time I did my final piece, I had figured out much more how to smoothly and properly put on the ground, the correct acid concentrations, inking fully into the crevices, removing surface ink, and successfully printing my desired image. My initial question of the concentration of the nitric acid and time to leave the plates in the acid were solved with Part 1 of the experiment, finding that hard ground needed 4 molar while soft ground needed 6 molar, each needing to stay in the acid bath for four minutes.
There were many differences in my final experiment than in my original plan. I assumed that after measuring the time and concentration for the nitric acid, I would be more or less done with the chemistry or scientific part of my experiment. After figuring out my constants, I assumed the prints would be mainly art related. Part 1 of my experiment proved to be simply the scientific testing I had expected, but I got different results than I had hypothesized. I found that soft ground rather than hard ground needed the higher molar concentration of the nitric acid. Using the hard ground was simply testing whether I had chosen the correct concentration in Part 1 and making designs in the ground, like I had assumed. Had I not previously worked with hard ground, I would have had to do more testing for this hard ground Part 2 of the project. Part 3 proved to be different than what I had expected. I thought that if I followed the techniques for using soft ground after doing my research, that it too would be a simple process. Using the soft ground though proved to be quite difficult. I had to reapply the ground more than once and practice techniques for getting the perfect amount of ground on the plate. I also had to figure out the correct time for the ground to dry. After I had figured out how to put the soft ground on the plate and how long to leave it I then began struggling with the fabric. I had to clean the plates and reapply ground more than once until I felt like the fabrics had properly removed the ground. Part 4 of the experiment I thought would just be a fun idea putting together Parts 2 and 3 using both the hard and soft ground. I realized that I had mistakenly removed ground on both sides of the plate and instead should have only etched one at a time. Even with the use of stopout, the acid managed to bite beneath the hard ground side leaving very faint lines. By the time I worked on Part 5, my final experiment, I thought I had tested, tried, and retried all aspects of the printmaking process from cleaning the plates to pulling the print. My final project proved to be another unexpected mini experiment when Mrs. Fitz and I made soft ground with the vaseline and hard ground. It was different than the soft ground from the can and again I had to redo the soft ground sides more than once until I felt like I had properly applied and removed the ground. I found in this final project that the homemade soft ground was easier to imprint in, while the store bought soft ground was easier to use a stylus in. Going into my project simply thinking I would be testing acid, time, and then seeing the effects of the soft ground proved to be completely wrong. From this experiment where I came to repeated dead ends and had to refigure what I was doing, I was able to learn about applying both grounds, etching, biting the plates, ink, inking the plate, and properly printing. This experiment entailed way more than I had expected yet gave me a greater understanding of printmaking in areas I did not even realize could be problematic.
http://www.answers.com/topic/burnt-plate-oil
http://www.sewanee.edu/chem/chem&art/Detail_Pages/Laboratory/Printmaking/PrintmakingLab_1&3.htm
http://www.worldprintmakers.com/english/pmhist.htm
Leaf, Ruth. Etching, Engraving, and Other Intaglio Printmaking Techniques. Dover Publications Inc: New York, 1976
Ross, John, Clare Romano, and Tim Ross. The Complete Printmaker Techniques/Traditions/Innovations. The Free Press: New York, 1990.
Thank you to Mrs. Fitz for working extra to help me finish my project and guiding me in the right direction. Also, thanks to Mr. Syler for teaching me how to figure all this computer stuff out.