Multiple Plate Aquatint
Although a single plate aquatint can create a broad range of tones, there are
some images that call for color. One way to create color aquatints is to draw a separate plate
for each color and print them all together. The following step by step description relates
what has worked for me in creating multiplate aquatints. Though I specifically describe
how one of my aquatints is done, these techniques are applicable to a wide range of images
and ways of working.
One difference between drawing an image for a single plate print and for a
multiple plate print is that for a multiple plate print each plate will only have part of the
information, while with the single plate it will be the entire print. Thinking of a plate as
only one piece of the print adds an extra challenge to making a print. It also broadens the
range of what you can do.
First decide what image to draw. In my case I choose a photograph to work from.
Then choose a "key" color. That is, decide what color to use for the first
plate draw to be drawn. This key plate will be used to transfer the image to the subsequent
plates. Therefore it is important that it describe as much of the image as possible. The key
color should have enough tonal variation and detail to produce an image transfer that has
adequate information to draw the subsequent plates in register with the key plate.
My color choice for the key is usually determined by this factor. I generally find that blue
is the color that will have the most information in the images that I choose.
Next I must decide what sort of aquatint to use. I sometimes want grainy
textural effects and so choose to do a coarse-grained very dense or ultra- dense aquatint on
the plate. One advantage of very dense aquatints is that they can be etched very deeply so
that they hold a lot of ink, and yet they still print leaving open areas for the other colors to
show through. They can print as a rich veil of color. Some prints that I have done look
very pointillist when viewed up close and are in fact essentially made of dots of color.
One limitation of coarse, dense aquatints is that they are not as good for fine detail.
Finer grained medium dense aquatints allow for more detail and still allow for colors to
show through each other instead of sit on top of each other as they tend to do with very
fine aquatints.
A particular challenge of multiple plate aquatint is doing color separations in
ones head. You have to decide what etch times and what paint outs will produce the
desired color blends. I generally etch about eight tones from light to dark, doubling each
subsequent etch time. As long as the general range of tones is in the ballpark they can
be adjusted by using extender to lighten the ink when printing the plate. I etch
plates so that they will print too dark if inked with unextended ink. This allows needed
latitude when proofing the finished plates. Also as the plate wears
down the amount of extender can be reduced to keep the plate printing darkly enough.
Once the key plate is etched the fun begins. To do a tightly registered
multiplate aquatint you need to know where to draw on the subsequent plates. I use an
image transfer method that I learned working with Kay Bradner, whose printing shop,
Katherine Lincoln Press, printed my 24" x 36" multiplate aquatints from 1980 to 1985. This
method uses two "L" shaped pieces of metal that are no thicker than the plates to be
printed. (Thicker registration bars could damage the blankets). One bar is attached to the
press bed, and the other bar is cut to fit snugly inside of the attached bar. The outer bar can
be taped or spray mounted to the press bed. The inner reg bar is in place when a plate is
being positioned on the press, and is carefully removed before the plate is run through the
press. Be sure to lightly file the edges of the reg bar that will be taped down. It goes through
the press and can cut the blankets if not properly beveled, especially if high pressure is
used. The reg bars need to be long enough to hold everything in position firmly, with
absolutely no rocking or variable positioning possible.
A guiding principle of multiple plate aquatint is to keep all the variable factors
as consistent as possible. The image transfer is done in exactly the same order as the
editioning will be done. It is also crucial that the plates are all the same
size and in the same position on the press bed for each pass through the press.
The paper should be soaked the same amount of time for the transfer as it will be for the
editioning. Undersoaked paper will stretch differently and can create an editioning
nightmare. It is also very important to use the same type of paper as will used in the
editioning. Different papers have different stretch characteristics. Even the same paper will
stretch at a different rate if run through the press 90 degrees off from the image transfer
direction. Make sure that the press pressure is where you want it for the editioning and
make note of it. It is also advisable to use the same blankets for the editioning. Even
temperature and humidity play a part. An image transferred in Atlanta and editioned in
Phoenix would probably be a real headache! As paper dries it shrinks, so the printing pace
of the image transfer and the editioning should be as close to the same as possible.
For many of my prints a blank plate the same size as the others is run through
the press before the key plate. This plate will partially pre-stretch the paper before the inked
plates go through the press. Though it is not essential, the stretch plate does help to reduce
the amount the paper will stretch after the key is printed. It can also be used to make the
number of plates be even, so that the press will be at the starting position after the last plate
is run and the completed print is removed from the press.
An image transfer is ready to be done when the paper is fully soaked, often
overnight, the plates to be transferred onto are beveled and cleaned, the press pressure is
set, and the blankets are in place. The backs of the plates to be transferred onto should be
marked so that you will definitely know the order that they were transferred onto. I scratch
lines on the back of the corner that fits into the registration bar.
If a blank stretch plate is to be used, then start the transfer
with that plate. Otherwise start the transfer with the key plate.
Ink and wipe the key plate and use the reg bars to position it on the press bed.
Blot the paper, or take it out of the damp pack, and place it so that it will be held under the
roller while each plate is being positioned for each of the runs. When transferring to more
than one plate the paper will have to cover part of the taped down reg bar for it to be
possible to place the movable reg bar while the paper is pinned under the roller. This
registration method does leave a reg bar mark on the print, and for the edition the print is
torn down to remove this mark. Run the plate through the press, and after making sure
that the paper is pinned under the roller, lift the paper and remove the key plate. Reset the
movable reg bar and place the second plate in position. Remove the movable reg bar and
place the paper over the second plate. Run the second plate through the press and, keeping
the paper pinned under the roller, lift the paper and remove the second plate. Be careful
not to smear the ink that has been offset onto the plate. If there is a third plate, use the
movable reg bar to position it onto the press bed and run it through the press. Repeat this if
there is a fourth plate. Since the transfer is done in the same order as the editioning, the
key plate is inked only once and must transfer the image to all of the following plates with
this one inking. The ink does thin out, but there is still enough ink even on the third run
to make an adequate image transfer.
EXAMPLE OF IMAGE TRANSFER DONE FOR THE PRINT, "EVENING REFLECTIONS"
There have been times that I have "finished" a print, only to realize during
proofing that a fourth plate should have been done. When this happens I do an image
transfer to create the needed 4th plate. I do every thing as I would for a 4 plate transfer. The
ink from the key is transferred to the second. third. and fourth plates, In this case, only the
fourth plate is etched. While the ink transferred to the already completed second and third
plates is cleaned off.
Warning! If the image transfer looks uncentered on the plate, or if the paper
slips out from the roller, start over! This includes waiting the full time to soak the paper.
For that reason I usually soak an extra sheet of paper. The success of the image transfer will
determine the success of the entire editioning process. A flawed image transfer will make
editioning much more difficult!
It is important to keep an accurate record of the image transfer process. I make
an image transfer diagram of each print I do. This diagram indicates the orientation of
the plate on the press, the location of the reg bar on the press, the press pressure, and the
order and color of each plate. Also note the blankets used if there are more than one set.
When I proof the finished plates I add notes to the image transfer record if any of the plates
need to be adjusted to make them print in register. This guide is used throughout the
editioning.
EXAMPLE OF AN IMAGE TRANSFER DIAGRAM
When the image has been transferred from the key plate to the additional
plates, the next step is to acid etch the plates. The offset ink acts as an acid resist and will
create a ghost of the key plate image on the plate. I etch copper plates in Dutch Mordant,
(1 part potassium chlorate crystals, 5 parts hydrochloric acid, 25 parts water), for 30 seconds.
I etch zinc plates for 15 seconds in 12 to 1 Nitric acid. After the etch, quickly wash off the acid,
clean the plate with kerosene to remove the ink, and degrease the plate with alcohol.
There should be a clearly visible ghost image of the key on the plates.
The image transfer is a crucial step in the multiple plate aquatint process and must give you
enough information from which to work. The less information there is, the
more the likelihood of error and the greater the need for cutting stencils and other time
consuming and less accurate secondary image transfer methods.
Once the plate is cleaned and degreased it is ready to draw on. I used to aquatint
it before the first paint out. This made the image transfer harder to see and forced me to
develop some rather involved methods using stencils. Now I always do the first paint-out on
an unaquatinted plate, which makes the image transfer much easier to see. This does increase
the risk of doing a paint-out and then doing a bad aquatint, but since the paint-out is under the
rosin it will mostly stay if a bad aquatint has to be washed off with alcohol. An unaquatinted plate
is also more vulnerable to grease stains from your hands. I always put protective
sheets of paper over the plate when I paint, and am careful not to touch the metal, but even
more care should be taken on an unaquatinted plate. The extra risk is more than offset by the
improved visibility of the transfer.
There are times when the second etch also needs the increased visibility of an
unaquatinted plate. In that case I remove the aquatint, do the second paint out on the
unaquatinted plate, and reapply rosin and do an etch. This re-application of rosin can be done a
few times if needed. Be careful not to over do it and etch so much of the surface that the transfer
disappears.
Sometimes instead of removing the rosin I can get away with making very
small "registration dots" during the first paint out. That is, I make tiny dots to indicate
important image information that I can barely make out on the first paint out. Be careful
to make the dots small enough so that they don't show in the final print. Registration dots can
be particularly useful on the yellow plate. Yellow does not show the dots even if they are
rather large, and yellow is usually not nearly as detailed as the other plates.
Though the key plate generally has more detail than any of the other plates, I
tend to have quite a bit of detail on all of the plates. This adds to the textural richness and
subtle color variation in the finished print. I sometimes use dense and even ultra-dense aquatints
for multiple plate aquatints, though medium-dense aquatints also work well. One advantage
of a very dense aquatint is that even after the plate has been deeply etched the rosin still
protects enough of the original surface so that the image transfer remains quite visible.
With a medium density aquatint the image transfer will get harder to see more quickly,
sometimes making color registration of the darker etches quite difficult.
Even with a good image transfer it takes practice to learn how to see the subtle
details. "Ghost" is an accurate description of the transferred image, as parts of it will seem
to peek out and then disappear, depending on the lighting and viewing angle. It is important
to have a good light source. A lamp on a moveable arm is ideal.
For several of my multiplate aquatints I have had to cut stencils or use other
secondary image transfer methods. Now that I paint out over an unaquatinted plate the need
for stencils is much less frequent, but there are times when the ghost image just does not have the
information needed and a stencil must be used. Sometimes I just cut a piece out of a proof of the
key plate in a shape that corresponds to the needed information, and place it on the plate to guide
that part of the paint-out. Another stencil method that I employ uses tracing paper.
The paper is taped to a proof of the key, and then the information to
be transferred is traced, along with information that is clearly visible on the image transfer so
there will be a guide to get the stencil properly placed. The tracing is then removed from the
proof. To delineate the information to be transferred the paper is either cut or holes are poked
into it with a drypoint needle. It is then placed on the plate that needs the information and
lined up with the image transfer on the plate. A fiber tipped pen is used either to trace dots
around the cutouts or to deposit spots of ink through the poked holes. These spots are used as a guide
during the paint out. I sometimes also cut a proof of the first plate into smaller pieces.
This way I can hold a print of the area being worked on as close as possible to that area. This is
particularly useful with large prints.
With the help of the image transfer, and possibly stencils, a plate is drawn for
each color to be printed. It is advisable to proof each new plate as it is completed. This gives
you a sense of how the print looks so far and serves as a guide in drawing the next plate.
These preliminary proofs are also the beginning of the color proofing. As always, the
printing is done in the same order as the image transfer.
When the plates are done it is time to do a full-blown proofing of the plates.
Set the press up as it was for the image transfer and have fully soaked paper ready. Mix
small batches of each color of ink to be used. Usually the image transfer and early proofing
have given me some idea of what mixture of ink I want and will help me guess at what
color blends to use and how much extender to use. I use china clay (kaolin) as an extender. It
can be purchased at ceramic supply stores. The china clay is mixed with #00 Burnt Plate Oil
and the ink. The inks are mixed and the plates are wiped. Then, referring to the image transfer
diagram, the plates are run through the press in the same order as in the image transfer.
Usually the first few proofs concentrate on arriving at the desired color mixes. Even with the
reg bar method plates can shift a bit so it is advisable to make a few runs before deciding what
adjustments may need to be made to get the plates to print on register, particularly if these
adjustments involve burnishing in the image or plate filing. Often the final refinements
happen at the beginning of the editioning of the print.
As the editioning progresses and the plates wear down the amount of china clay
used in the ink mixture is cut back to compensate for the reduced ink holding capacity of
the plates. I have found that the plates print a little darker at first, partly because of the
extra ink held by the image transfer. After about 25 prints the plates seem to settle into a
stable printing stage that may last for a hundred prints or more. The plates should be
periodically cleaned with caustic soda or the buildup of ink will make them print lighter.
Finer and less dense aquatints will break down more quickly and may need steel
facing if larger editions are wanted. I hope that this article will be useful to those of you
who do, or are considering doing, multiple plate aquatints. Though the technical aspects
can be quite challenging, the results are well worth the effort.
Stephen McMillan © 1988, last updated 2002
