In the last post, I talked about creating aquatint tones using hard ground and paint markers to cover the plate and protect it from the acid.  In another process, the acid can be painted directly on the plate to create subtle effects and soft edges.

Spit bite: painting acid directly onto the Aquatinted plate
Spit bite: painting acid directly onto the Aquatinted plate

The plate is covered in an aquatint ground (a ground of tiny speckles that will result in very small raised points of metal when etched.  See How Tones Are Created in Etching for more detail on this ground.)

Next, any parts of the plate that need to be protected from the acid are covered in a solid acid-resistant ground, such as liquid hard ground. This appears coffee-colored in the above photo.

Now the fun begins.  Using a weak solution of acid and an animal hair brush, the prepared plate is literally painted with acid. Acid can be stroked onto the plate, dripped onto it, or dripped into puddles of water that have been painted onto the plate.

Because the acid is weak and is depleted quickly in this process, areas that are to retain ink need to be painted over and over with the acid, until the etch is deep enough to hold the desired amount of ink.  It is not possible to tell just

Spit bite plate
The plate is stained from the acid

from looking at the plate exactly how deep the etch has become, so it is important to have a sense of how many times a given area has been painted with acid in order to gauge progress.  The application of acid to the plate in this manner results in the plate appearing stained, but the varying color of the stain does not relate closely to the eventual tone in the print.

When the artist determines that the spit bite is deep enough, the plate is flushed with water, and dried.  All of the grounds are removed, and the plate is inked, wiped, and printed to check on progress.


Using paint marker for highlights in the waves
Using paint marker for highlights in the waves


For this image, however, I chose to continue to develop tones for areas representing sand and surf.  I used paint marker to protect the highlights in the waves.


Another technique I like is to draw over the aquatint ground with a china marker (grease pencil).  This is another way to create subtle gradations of tone in the aquatint.

Using a china marker for subtle gradations in the sand
Using a china marker for subtle gradations in the sand



Again, development of tones proceeds by soaking the plate in acid,  then using paint marker and china marker to cover more of the plate and soaking in acid again.


















Here you see continued development of tones for sand and waves. Eventually the areas still exposed to acid are very small.


Eventually the area being etched is very small.
Eventually the area being etched is very small.





Finally the grounds are cleaned from the plate.  The bare plate gives some idea of how the plate will print if you look at how light reflects from the surface.  The spit bite areas are somewhat deceptive because of the irregular acid staining.

The bare plate after grounds are removed.
The bare plate after grounds are removed.






Next step is to ink and wipe the plate, and print it on the etching press to check progress. Here is a view of the press, which has rollers above and below the traveling bed. Note the felt blankets folded up out of the way, waiting for the plate and paper to be set upon the bed.


Here is a view of the etching press


The inked plate on the press bed.
The inked plate on the press bed.







The plate is inked and the surface is wiped with rags.  Now you can see more clearly how the acid has affected the plate, especially in the spit bite areas.



Damp paper is placed over the inked plate, and covered with soft felt blankets. The resulting sandwich is rolled through the press.

















Note the plate marks visible from the back side of the paper after the plate has gone throug


h the press.


as gone through the press.





Black and white proof of the plate









Here is the black and white proof (print) of the etched plate.  The spit bite has produced a brooding grey sky of indistinct clouds.

The next process in developing this image will be mixing colors and proofing the plate in color.


10 thoughts on “Subtle Effects in Etching: Spit Bite

  1. Katy Jackson says:

    Amazing work! I’d love to try this to get a softer painterly effect!! What solution do you use for the spit bite? Am assuming it’s copper sulphate on the zinc. Some places I’ve read it’s a stronger solution than what is normally in the bath, but you are suggesting a weaker solution.
    thanks, Katy

  2. Thanks for your comment Katy! I use Nitric acid on the zinc – it is originally mixed at 8:1, but I use the acid for years between mixing new batches, so it is partially spent and therefore a bit weaker than that. I imagine that it would work with Copper Sulphate also, but I haven’t tried it. I use an animal hair brush that I bought in Japan – a calligraphy brush. It seems to be holding up well to use in the acid. Notice that it does not have a metal ferrule. The development of the spit bit is not easily visible as you work – the metal changes color and so it can appear that it has etched more than it has. I try to keep an idea in my head of how many times an area has been painted so as to calculate roughly how many seconds of acid exposure it might have had. Like many etching processes, it is imprecise, but fun to experiment with. Come back and show us your experiments!

  3. Hi I read with interest your post.

    I have done a little soft ground etching b g but am interested in doing spit bite I think. What I’d like to do is paint ferric chloride directly onto the copper plate without a ground or row on or spray paint. I understand that I would need many applications of the FC in order to get the etch. Would this work to any degree. Would the etch hold ink without an squaring base. I assume it would probably result in the etch being like foul bitingbuttgar might serve my purposes. Alternatively instead of rosin or acrylic spray paint from a can do you think up could use liquid acrylic paint in a fine mist spray bottle.

    Thank you.

    • I have never worked with ferric chloride, so I don’t know how this would work. I imagine an open bite of spit bite would indeed resemble a foul bite and not a nice tone. I have lately played a bit with steel or aluminum plate and copper sulfate – those are supposed to give a tone without aquatint, but I find it less than satisfactory as it produces and uncontrolled grey tone and not a rich dark. I should imagine a liquid acrylic paint in a fine mist should result in an adequate aquatint ground upon which to try spit bite. Let me know how it comes out! The key is to remember that it takes many many applications to equal the effect of soaking in the mordant. I try to keep an idea in my head of how much time the darker areas have been exposed to the acid in the spit bite process.

  4. I just did a print which I like for its uncontrolled abstract values. Much what I was looking for. However no aquatint at all. What I found is that the ferric beads up on the plate. I had to go over it many times as you say. O read that spit bite comes from adding saliva presumably to make the acid or ferric to flow more smoothly. And that now etchers use gum Arabic. I’ll try that next. Am using Kathan Browns aquatint book as my main guide
    Will send you a picture of the print on my next message. Its not on this phone yet. Thanks.

    • Hi, I sent you my email privately so you could email me your image. I don’t know about using saliva – I never heard that! I learned about spit bite from the Ross and Romano “the Complete Printmaker” book. I sometimes use water to wet the plate so the acid will “bleed” into the wet spot. And of course, as the acid that you paint on gets used up in reaction, then it becomes inert as water, so your next stroke will bleed from the center of the stroke out into the wet area. I am not sure why the ferric beads up on the plate – nitric does not, but then I usually use a pretty wet brush. I checked out your website and enjoyed looking at your work.

      • Thanks Julianne. I have 2 websites. has older things including fiber beads and collages . my new site never up to date is for printmaking .

        I reread the material from crown point press and apparently there’s even a formula for mixing water and him Arabic with the acid or ferric to be able to handle it in the copper. New trials coming. I sent the image to your email. Thanks

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes:

<a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <s> <strike> <strong>