Please note: This article is meant to be a resource to printmakers and other interested people. Permission to reproduce this article is hereby granted as long as my name, Stephen McMillan, stays on it in all forms of reproduction. The Aquatint Class section has step-by-step examples of prints in progress. The one using creep-etch is: Skagit



While studying printmaking in London in 1970, I was introduced to

creep-etch. This etching technique creates gradual tonal change over an aquatint by

allowing the acid to gradually "creep" across the plate. This produces an effect that is

not possible when a plate is submerged in the acid all at once.

I used creep-etch from time to time to achieve tonal changes in the skies of

landscape images. Then in 1977, while working on a single plate image of a foggy

orchard, I realized I would need to use a whole series of creep-etches to accomplish the

desired range of tones. The technical challenges of this print, "Morning Fog", inspired

the development of my personal system of creep-etching. Over the years I have

developed methods to keep track of multiple creep-etches on single and multiple plate

aquatints. The following article details these methods.


Before I do a creep-etch I first draw a diagram of the plate and use it to

work out the etch times of the creep-etch. The diagram, often with a rough sketch of

the image, is drawn in pen. I use a pencil to draw in possible creep-etch times. I use

test plates and educated guesses to guide me in choosing the etch times. I often draw

and erase a few etch progressions before I settle on the times to be used.

When I have decided on the etch time progression, I draw a line beside an

edge of the diagram that represents the edge of the plate. On this line representing the

plate edge, I write numbers to indicate when the acid should cross that part of the

plate. These numbers are in the reverse order of the etch time numbers. For example,

the point to be etched the longest is where the creep-etch will start, and is marked with

a zero to indicate no time elapsed before the acid should arrive at that point. The area

to be etched the shortest time will get the highest elapsed time number of the

creep-etch since it indicates where the creep-etch ends.

Sometimes a plate will be removed from the acid and washed as soon as the

creeping procedure is completed, but in many cases the plate is submerged entirely for

a period of time after the creeping is finished. For example, a creep-etch of

ten-to-sixty minutes would be totally submerged after fifty minutes and would come

out in another ten minutes at sixty minutes.

The time at which the plate is to be removed from the acid is specified on

every diagram as the "OUT" time. The "OUT" time is the total elapsed time on the

stopwatch. If the plate comes out immediately after the creeping procedure, I write

"OUT" on the diagram beside the highest number in the creep-etch. If the plate is to

be submerged completely for a time after the creeping procedure, the "OUT" number

will be the time of the creep plus the time of total submersion.

Creep-Etch Diagram Example

Once the diagram is complete, the information needs to be applied to the

plate. I do that by sticking tabs or strips of masking tape on the back of the plate so

that they stick out from under the plate. On these tabs I write numbers that correspond

with the acid coverage times on the diagram.

Information Transfer Example

As successive creep-etches are done over a plate, the cumulative etch times

may vary a great deal from point to point on the plate. I use the creep-etch diagrams

as records of the etches that have been done. To determine the cumulative etch time

of a particular spot on a plate, I add up all of the etch times over that spot as recorded

in the diagrams. That number, plus any other etching done over that spot, is a close

approximation of the actual time that spot has been etched in the acid.

In designing a new creep-etch progression, I often I add up cumulative

etch times for several spots on the plate and transfer them to a new diagram. These

cumulative times are also useful in making an educated guess of what tones have

been etched into the plate so far.

For some images I only want to do a single creep-etch and then even out the

etch times across the plate. To do this I do a "reverse creep-etch" which simply

progresses in the opposite direction of the first creep-etch and thus evens out the etch

times. Variations of this can be used to even out the etch times in darker areas after a

series of creep-etches have been used for lighter tones.

In some images I do multiple creep-etches between paint-outs. For example,

on the red plate for the print' "Crater Lake" I did five creep-etches from five

different directions before the first paint-out. Almost all of the etches on the three

plates for "Crater Lake" were creep-etches, and most were multiple creep-etches.

Creep-Etch Diagram for Red Plate of "Crater Lake"


Since creep-etch requires that you spend extended periods very close to the

acid, it is particularly important that you wear proper lung and eye protection and that

the acid area have an effective fume removal system.

A basic creep-etch is just a matter of allowing the acid to gradually move

over an aquatinted plate. I used to lower the plate into the acid by hand, which does

work, but is hard to control and can get tiresome for longer etches. I now use a

gradual acid submersion method that is much easier to control.

I begin by propping up the acid tray, so that it slants at about ten degrees

from level. Next, I pour a small pool of acid into the low end of the tray, leaving

enough room so that the plate can be set in the tray and still be completely out of the

acid. It is important that the plate is dry. Acid will be pulled quickly into any damp

area. Now the stage is set for the creep-etch to start.

I set my watch to the stopwatch mode and place the plate in the tray. I push

the plate toward the acid until the acid is touching the zero point or line on the plate.

When a creep-etch starts at the edge of a plate, I carefully ease the plate into the acid

until the acid climbs the beveled edge of the plate and begins to move onto the plate.

At this point I start the stopwatch. The zero line for some creep-etches, however, is

located some distance in from the edge of the plate. In these cases, the plate is quickly

slipped into the acid until the acid arrives at the zero line. Then the stopwatch is

started and the creep-etch commences.

Example of Creep-Etch in Progress

The creep can be accomplished by either nudging the plate deeper into the

tray or adding more acid to the tray. I often use a combination, pouring the acid from

a glass measuring cup, and nudging the plate gradually farther into the tray with a

small piece of wood, such as the handle of a brush. Depending on the speed of the

creep I may have to nudge the plate frequently or may wait a minute or more between


A creep-etch requires constant or near-constant movement of the acid over

the aquatint to achieve an even, unstreaked tone. This is particularly true for quicker

passages over fine-grained aquatints.

By using the slanted tray method it is possible to make the acid move at a

very slow but steady pace up the plate. With gradual pouring and/or incremental

pushing of the plate, the leading edge of the acid will be a small wall moving very

slowly up the plate. Sometimes the movement of the acid on the plate is so gradual

l that it can barely be seen, such as when it is only moving an inch every five minutes.

If the acid is too slow in reaching a specific area, it can be gently pushed

into that area with a feather or brush. If the movement is too rapid the plate can be

slightly pulled out and the acid carefully blown back. Clearly, you should be very

careful if you try to blow the acid, and you should wear eye protection at all times.

A major unwanted acid incursion may require a rapid removal and washing of the

plate. If this happens, try to remember to stop the stopwatch (but don't zero it). After

the plate is dry the creep can be resumed from the location where it was interrupted

and the stopwatch started running again.

To lessen the chances of streaks, a single creep-etch can be done as a few

shorter creep-etches. For example, a zero-to-sixty-minute creep could be done as three

separate zero-to-twenty-minute creep-etches, thus evening out the variations of the


Sometimes I want to do a creep-etch that does not travel as a straight line

across the plate. Generally this requires that the tray be closer to level so that the acid

can be feathered into the desired areas. When the tray is close to level, any unevenness

in the plate is more likely to affect the progress of the creep-etch across the plate. For

this reason it is advisable to make sure that a plate is reasonably flat before planning

to do a creep-etch on it.

There may, however, be occasions when unevenness of a plate will be

intentionally created to alter the way the acid advances over the plate. For example, I

have set small pieces of wood under a plate to gently bend part of it up and thus alter

the progress of the creep-etch. This method is most effective for larger plates since

small plates don't bend sufficiently. The closer the plate is to level, the easier it is to

feather acid into nonlinear shapes on the plate. This creep-etch feathering technique

resembles a process called spit bite, which is another way of creating detailed tonal

variation. Spit biting is accomplished by gradually dripping acid onto a plate with an

eye dropper, paint brush, or other tool.

Close attention must be paid to the stopwatch to keep the acid moving across

the plate at the desired rate. After five minutes the acid should draw a line across the

plate between the two tabs with the five-minute marks. If you plan to use a feather to

move acid into certain areas it helps to have the diagram at hand to determine when

and where. Once a creep-etch is started you are pretty much stuck there until it is

done. I occasionally do ones that last up to two hours, and yes, it does get a bit boring!


The key plate for the print "Loon Island Outlook" is a good example of

using creep-etch to create an image. Only four paint-outs were needed to create a full

range of tonal values.

Creep-Etch Diagrams for "Loon Island Outlook"

Before the first paint-out I did Etch Series #1. This was a combination of

two creep-etches, one from the top and one from the bottom, that met in the middle of

the plate.

I painted out the sky and the lighter parts of the water, then did Etch #2.

This creep-etch ended three-quarters of the way up the plate, after which the plate was

rapidly totally submerged in the acid. The arrow in the diagram is used to indicate the

essentially immediate passage of the acid over that area. After Etch Series #2, I painted

out the most distant islands and the rest of the water.

Etch #3 was specifically designed to give the central island a slight tonal

gradation laterally. This creep both begins and ends within the plate, as indicated by

the arrows. This etch was done by rapidly dipping the plate to the zero line, doing the

creep over 14 minutes, and then quickly submerging the whole plate and removing it

after six more minutes had elapsed. After completing Etch Series #3, I painted out

everything except for the darkest parts of the foreground.

Etch #4 was used as a "reverse creep-etch" to even out the etch times in the

darkest tones. The circled numbers are the cumulative etch times from the first three

diagrams, and were used to design a reverse creep-etch that would come close to

evening out the etch times.

This completed image was transferred to two other plates, and creep-etches

were used on these subsequent plates to create a rich variety of color and tonal change

in the completed three-color print.

I have found creep-etch to be very effective for landscape. It can also

provide useful effects for a broad range of imagery on single and multiple-plate

aquatints. The methods that I have detailed here are only the beginning of what can be

done using creep-etch over aquatinted plates. I encourage all interested printmakers to

experiment with creep-etch.

Stephen McMillan © 1994 (revised 2000)