Experimenting with the saline-sulfate etch.

Since Tiger Lily Press

 will be moving towards being a more "green"

printmaking studio once our move is finalized, it was finally

time to start experimenting with some alternative & safer

etching techniques.

So a small group of us met at

the studio today to experiment with

the saline-sulfate method for

etching zinc plates.

Being an "old-school" printmaker, I was mildly

suspicious of using anything but

nitric acid to etch zinc!

To begin with, equal parts of common table salt

and copper-sulfate are mixed together. Since I was

only mixing enough for a small tray,

 I used 3.5 oz. of each.

Added to that is 2 cups

of hot water, stirring until 

the mixture has dissolved.

(the solution begins as a murky

blue-green, and turns a clear green

as the crystals dissolve)

This was added to the etching tray and 

an additional four cups of hot water

were added to further dilute it.

This made for a somewhat "hot" bath.

In the future I may try diluting with an extra

one or two cups of water and experiment again.

A weaker solution will probably work

more effectively with delicate

processes such as aquatint.

Immediately upon placing a coated plate into the solution,

the exposed zinc turns black and begins to 

throw off a lot of copper colored sediment.

It was quickly apparent that the plate and/or

tray would need to be agitated to keep

the sediment from effecting the etching process.

Below are my two printed test plates. The first is a 

hard-ground coated plate with line work

etched in increments. Beginning at 5 minutes,

ending with a 20 minute etch. Since the acid

was stronger than I expected, I wish that I had started

with a one minute etch.

The second print is aquatint, etched in 15 second increments.

The darkest square, on the right, was etched for 1.5 minutes.

Elaine's test plate being printed by Brian. She used hard

ground, scratched off the plate, and then 

coated with a spray paint aquatint.  It was

etched for approximately 25 minutes.

(her plate can be seen in the tray in photo #4)

Brian tried several test plates with aquatint. Notice how 

much crud is on his plate in this first photo! This plate was 

etched up to seven minutes for the darkest tone.

For this plate, the rosin was applied by

using a rosin dust bag for a grainy effect.

Sections were blocked out with

stop-out varnish and (if I remember correctly), the plate

was etched in several increments for

up to five minutes.

The last experiment of the day was an open bite, etched 
just for a minute or two. At this point the acid
has become a mess!
The 2nd photo shows how the plate turns
black when exposed to the acid.

I don't have a photo of this plate printed,
but there was enough "tooth" to the etched area
to print a pale grey tone.
We carefully poured the remaining solution
into a plastic jug to save, leaving the sediment
in the tray.


So in conclusion, this "old-school" printmaker
is most likely a convert to this technique. It definitely
worked better than I expected!


For a downloadable PDF file on the technique, click here


Visit the nontoxicprint website for 
more info on safer printmaking options.