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TECHNICALITIES...

So what is an etching?

Photographed by David.

Above is an image of print and block. In this case the block is a zinc plate. To arrive at a print the zinc plate is first etched. And this process while simple in concept still requires a few steps to be followed, as described in Detailed Notes on Etching Process below. In essence a coating of something both acidproof and waterproof, usually a bitumen or tar of sorts is used to coat a zinc plate. When a needle is used to draw an image upon the prepared plate, the action reveals the zinc underneath. When the plate is then immersed in a weak nitric acid solution, those areas opened up by the needle are etched, small cavities and canyons are created by the chemical reaction. After lines have been etched, the plate is cleaned and then sprayed with a bituminous substance to create an irregular pattern of minute dots. By the application of more bituminous fluid with a brush, at first white areas are painted on the block. After each application of bituminous liquid, the plate is momentarily immersed in the nitric solution mentioned earlier. By this incremental method of painting and etching, graded texture can be made across the plate. The varying texture over the plate will hold a varying amount of ink for printing.

And what is an edition of fine art prints?

An edition is taken from a printing block to the specifications of the client when; color, printing technique, paper type and the number of prints to be included in the edition are all settled, and a BAT print or ‘bon à tirer’ has been produced.

Editions are priced according to edition size, print size and difficulty. Postage is not included, however postage can be arranged and included in the cost.

A further breakdown of steps to an edition of fine art prints...

When a plate, whether in metal or linoleum is completed, and a print arrived at which satisfies the artist, it is time to consider an edition of the print. The number of prints included in the edition must be decided upon. An edition comprises of a number of prints which are the edition proper.

There are other prints that could be assumed to be within the edition as well. A number of artist's proofs are usually taken equal to roughly 10% of the edition proper. There is a BAT too or ‘bon à tirer’ print, with which the edition prints are compared for inclusion in the edition. So, an edition of 10 prints would most likely have a BAT print and at least 1 AP or artist's proof.

Of course, all the state proofs, SP's and trial prints or TP's or color trial proofs, CTP's to name a few could be considered connected to the edition as well.

The type and size paper must be chosen...

It falls to the client to purchase the necessary paper for the edition plus 10% for possible failure rate. We can however arrange for paper. There is a huge range of paper types suitable for printmaking which can lend so much to the image.

Ink and colour must be decided on. Yet again it is up to the client to provide the ink for the edition and 10% failure rate. Any excess is retained by the client of course and may be used for future editions. We can also arrange for ink.

Once a size of the edition has been settled on, the paper chosen and ink decided on, and we have a fair idea of the difficulty in printing the plate, we can then offer a quote. 

The Etching Process in Detail...

1. Choose a zinc sheet or copper sheet​​

Zinc...
+ faster etch
+ when drawing on prepared plate, lines are of higher contrast with hard ground, easier to see
+ usually painted on reverse and protected on front with clear contact, so unscratched

- more prone to under-biting
- more expensive

Copper...
+ finer lines are achieved with less chance of under-biting
+ cheaper

- longer etching time

2. The metal plate chosen is inspected, least damaged side is usually preferred. Wet and dry sand-paper can be used to deal with most scratches, bought at a hardware store. When wet and dry sand-paper is used, the metal plate is sanded wet, flushing the plate from time to time with water. If the scratches are deep 180 grit paper is used first. Next, something like 400 grit paper is applied, then 800 grit. And finally 1200 grit or higher. A mechanical buffer could also be used.

Once the surface has been sanded and polished, plastic contact can be affixed so as to protect the surface. The back of the plate is then covered in contact too. Very deep scratches can either be ground out with a hand grinder or burnished, which will be discussed later. In other words, it's best to possibly begin with an unscathed metal plate.

3. The reverse of the plate must be protected from the acid solution. Plastic contact can be adhered to the back. A suitable enamel spray like Pot-belly black can be sprayed on back. Hard ground can be brushed on or sprayed on the back but will get scuffed and needs to be retouched continuously. 

4. The metal plate's edges are filed to roughly to a 45-degree bevel. Then scraped with metal ruler or scraper tool. Can even be sanded and polished. Corners can be rounded too. The plastic contact protects the chosen surface through this process. The bevel and rounded corners reduces chance of paper creasing during printing, or simply cutting paper and blankets. 

5. Now the plastic contact is removed from the side to be etched. Plate surface must now be cleaned. Turpentine can be used to remove grease. Methylated spirits removes residual plastic contact glue and residual turpentine. Finally, chalk and acetic acid or vinegar are combined on the plate to make a stiff paste, which is worked over the plate, thoroughly rinsed off with water and then dried.

Plate is now grease free, smooth, bevelled and ready for grounding. 

For now, we will proceed as for a line etch...

6. Application of hard-ground.

Plate is placed on a slip sheet of waste paper which helps transporting the heated metal plate and provides some protection for roller as hard-ground is applied. Plate is heated on hotplate till the knob of hard-ground is able to be smeared on and is runny and glossy. A rubber roller is run back and forth over plate to evenly distribute the hard-ground. As per inking up with a roller, allow roller to spin a little between rolls, for evenness of ground applied, and to rest the roller from constant heat which will damage the rubber roller. Care must be taken not to overheat the ground. Care must be taken not to melt, or overheat the rubber roller. Don’t leave roller rubber side down ever and certainly not on the hotplate for it will melt. Hard-ground rollers are used only for hard-ground, soft ground for soft etc. If you are having difficulties with even coverage or dust and grot, check the roller and see if it is worth giving it a clean with turps. The resulting covering of hard-ground need only be the colour of honey. Allow the hard-ground to cool. A thick black covering of hard-ground presents problems in drawing and etching. Hard-ground is essentially an acid resist or stop-out or block-out.

7. Making a line.

A line is achieved by drawing an etching needle across the prepared surface. Wherever the metal of the plate is revealed by the needle, wherever the hard-ground has been scratched away, the acid solution can access the metal plate, and etch it. The revealed metal will be eaten away, these areas will hold ink in the intaglio printing process. Crosshatching, stippling and many more drawing techniques can be employed without ever worrying about aquatinting. Many drawing tools exist and many implements can be used as drawing tools, like a wire brush, scalpel, roulettes, anything really. 

8. Etching a line

Suitable protection is worn, acid proof gloves, vapor mask and goggles. The plate is immersed in a suitable solution.

Nitric acid diluted in water for zinc.
1 part nitric to 6 parts water = line etching solution.
1 part nitric to 11 parts water = line etching & aquatint solution.
1 part nitric to 16 parts water = aquatint & fine line etching solution.

Dutch mordant is used for copper, which is a solution of Hydrochloric acid, potassium chlorate and water.

Tiny bubbles will begin to appear wherever the metal is exposed to the acid solution. These are swept away with a feather from time to time while the plate is submerged, which helps to discourage under-biting or fouling. One need not constantly feather the plate though attention to the etching process is needed at all times.

The depth of line is related to the length of time plate is immersed in the solution. The depth of line is checked by removing the plate from the solution. The plate and your gloves are rinsed thoroughly and then plate is dried. With eye, magnifier, needle or even fingernail (digital feeler gauge) the depth of line can be inspected. If a needle can be lodged in a line without fear of it skidding out then ink is going to be retained in the line, ditto with fingernail. Any amount of time in the solution is going to etch the plate, light lines can be saved by painting liquid hard ground over them as required. Zinc will etch quickly. Up to 15 seconds will probably result in a light line which retains little ink. The deeper the etch, the longer in solution, the darker the line, which retains more ink. A deep line should be well and truly established after 3-4 minutes.

Copper in Dutch mordant reacts slower than zinc, yet is checked regularly for depth of line. Line etching is possibly checked for depth many times until the artist is happy.

If at any time hard-ground begins lifting off the plate arrest the process by removing plate, rinsing thoroughly and probably re-applying hard-ground and all that entails.

9. When an acceptable depth of line has been achieved...

Hard-ground is removed with turpentine and a rag. Oil from turpentine is removed through applying slurry of chalk and acetic acid again. Plate is thoroughly rinsed with water and dried. Plate should be ready to ink up and proof. 

The line etch may be worked on further, blocked out and added to. Line has seemingly endless potential and can comprise the image. Many ways of mark making can be experimented much in the same manner as drawing, particularly pen and ink techniques.

If the final image is to have tonal elements, then the aquatint process can be used. Unless working intuitively then artist should have either a working sketch, coloured line proof or a good idea of the image wanted. This working sketch or the original concept image or drawing is useful to refer to during the aquatint process.

10. Aquatint
The plate is cleaned with turpentine, methylated spirits, and chalked and dried as described previously Liquid hard-ground is brushed onto plate wherever there is absolute white in the concept image. This process is called blocking out. The first spray of liquid hard ground can be applied now, it can really be applied before first block out for white. Once the spray is dry...

The metal plate is immersed in an acid solution appropriate to its type, for a length of time. The plate is removed from the acid solution and thoroughly rinsed in water.

The first shade of 'grey' is now blocked out anywhere on the plate that ''grey' appears in the concept image. The metal plate is immersed in an acid solution appropriate to its type, for a length of time again. The plate is removed from the acid solution and thoroughly rinsed in water, and allowed to dry.

This cycle continues until only the utterly black tonal areas are still open to etching. Once black has been etched then...

11. Time to proof the plate again, or for the first time...

Hard-ground is removed with turpentine and a rag. Oil from turpentine is removed through applying slurry of chalk and acetic acid again. Plate is thoroughly rinsed and dried. Plate should be ready to ink up and proof. 

Amount of time the 'sprayed plate' remains in acid solution determines depth of bite, and depth of tone. The longer in the solution the darker the tone will be. So the lightest grey tone would have been blocked out after it was etched for the least time. The next darkest grey would have been blocked out after a short time and so on until black is etched.

Photographed and compiled by David. Images are derived from a digital microscope.

The Etched Plate in Detail...

Above is an image of a copper test plate (at top) and test print. The smaller images are taken with a microscope and are samples of the plate and paper.

The copper plate (above top) is rougher and retains more ink on the left hand side. This tooth or texture reduces as it approaches the extreme right hand and unetched end. ​​

Each image also shows the transition between one tone and the next. This texture is how ink is retained on the block.

Below the plate is the resulting print.

Before I had a microscope, a fairly average camera was used in conjunction with a stand mounted magnifying glass and zoom lens to acquire images of an etched zinc plate. Although no match with the microscope, the combination of lenses gave reasonable results. In some images the needle or scribe is included for an idea of the scale...

Photographed by David.