Aluminium Etching

Little Tomo. . .

 

I've finally figured out why I love etching so much, its one of those things that I discovered by chance, and that comes as easily as breathing. While some people listen to music or go jogging to forget their problems, I escape in my art. Its almost like meditation, because I can block everything else out except the image before me, and by the end I feel completely revitalized. 

I guess that's what Pablo Picasso meant when he said, "Art washes away from the soul the dust of everyday life."

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Ingredients for Copper Sulfate Etch :

(Remember to put on gloves, dust mask, and safety goggles when handling the crystals to avoid touching or inhaling dust particles).

• 600g  Copper Sulfate.
• 150g  Salt (NaCl).
• 156g  Sodium Bisulfate (NaHSO4).

• 200g Water

(the solution can be used multiple times, but will occasionally need more of the dried sulfate ingredients added to it as it becomes subtly weaker each time it's used. You can tell its time to add more when the liquid begins to loose its 'blueness' and the plates start taking longer to bite).

Lighter blue sulfate = Softer bite.

Darker blue sulfate (stronger solution) = Harder bite,  lines in plate will be more defined.
 

Method (Preparing the plate) :

1.  Identify which side of the plate you wish to use (usually the side with less scratches or markings, though these can sometimes add to the character of the print).
2. Degrease the plate. - -English Whiting Powder added to a dash of water (till you get a toothpaste consistency) and apply in a circular motion using cotton wool, rinse under tap using wool.Make sure you don't touch the surface of the plate once its been degreased. 
3. Dry plate using hairdryer.  
4. Prop the plate on a 45 degree angle and lightly apply Ground using a large brush. (Soft Ground - Texture  OR  Hard Ground - Line). Once evenly applied lay the plate on a flat surface and allow it to dry.  (Unfortunately the hairdryer doesn't help during this stage).
5.  Scratch image into the plate . . . Remember that the image will be reversed when printed.  (Ive also noticed that when lines are drawn too close together there is a risk of them merging completely when put in the copper sulfate. This creates a black splodge when printed . . .as shown below).

 First Test Plate, 2010. Stage 1. (top left corner). 

- Tip: Any unwanted splodges or blemishes can be disguised using Bitumen (as shown bellow in step 5-7, Biting the Plate).    

Method (Biting the Plate) :

1. Fold some tape in half and stick it onto the back of the plate so that it becomes a handle.
2. Place the plate, image side up, into the Sulfate, making sure that it is completely submerged, and the end of the tape from the back is sticking out of the Sulfate. 
   Allow the plate to bite for around 20-40 minutes. Every so often red 'fish eggs' will appear along the lines that you scratched into the plate. Personally, I like to remove the red bubbles by rinsing the plate over a bucket in the sink, before placing it back in the Sulfate.  
   Keep in mind that the time it takes to bite the plate will vary depending on the strength of the Copper Sulfate, how dark you wish the lines to be and how fine your line work is. (My work is usually comprised of delicate line work which is why I tend to keep my plate in the Copper Sulfate for closer 40 minutes to make sure that it is well and truly bitten).
3. Using Turps and an old rag outside, remove the ground from the plate so that it is completely clean.
4. There's nothing worse than cleaning the plate and realizing that the lines are only half visible. If this does happen don't worry, the bonus for using Aluminium is that it's a rather soft metal that can be reworked without the use of the sulphate.                                                                                                                                        Tip: Using an etching tool scratch over the lines which didn't form properly in the sulphate. It'll take a bit longer, but it's better than tossing the entire plate and starting over. The reworked lines can also appear more 'clean' than the sulphate etched lines, and if applied over areas with sulphate-etched lines it can add a new layer of depth to the work - you also don't have to worry about the lines being too close.
5. At this point you have the option to print the plate as it is, or to continue working the plate and add tone.   If you do intend to continue by adding tone its good to do a test print so that you get an idea of where that  tone would work best.
6. Using Bitumen, paint over the areas which you want to remain white. For a more gradual variation in tone you can also dab the plate using a stippled brush, making sure that some areas are left untouched by the Bitumen. 
7. Once the Bitumen is dry, place the plate in the Copper Sulfate for 2-4 minutes, rinsing the plate when necessary.  
   Tip: You can also get interesting lines and textures by using a paintbrush to remove the bubbles while the plate is still submerged in the Sulfate.
   
8. Dry the plate using a paper towel and repeat steps 5 and 6, but this time rather than painting the areas that you wish to be white, you paint over the areas that you want to be light gray. Continue until you have however many shades of gray that you want (depending on exposure time to the Sulfate, you can usually get around 4 different shades before it becomes too dark). This is also a good opportunity to disguise any blemishes on the plate . . . 

First Test Plate, 2010. Stage 2

Method (Printing) :

1. Create a registration sheet so that the plate and page line up perfectly when printing.
2. Put on gloves (Trust me, you'll need them).    
3. Soak paper in a sink or tray. (Heavy paper such as Stonehenge, Dutch Etch or Fabriano).
4. Prepare the ink. . . If your soft handed its best to use Graphic Chem. ink, don't worry about mixing it with anything.  Its also good to use if your in a hurry as it isn't too sticky.  Otherwise use Van Son mixed with Graphic Chem. Easy Wipe as it will give you a rich, inky black. Just make sure that you mix it vigorously first so that it's warmed up.
5. Using cut up cardboard spread the ink over the plate and into the grooves.
6. Take off excess ink with a new piece of cardboard before wiping the plate with a scrap of Talitin.
7. Using old phone book pages, gently rub the plate in circular motions - Don't apply too much pressure.
8. Clean the edges of plate with a rag.
9. Take of gloves (double check that your hands are clean because the paper will absorb any fingerprint and smudge).
10. Remove paper from the sink and blot dry between two clean towels. preferably white towels so any dirt or ink smudges are easily visible.
11. Place your plate over the registration on the press and carefully cover with the etching paper. (The water mark on the paper can sometimes add to the print).
12. Cover the etching paper with butchers paper and padded blankets before slowly putting it through the press (I like to put it through twice if there isn't a line behind me).
13. Gently wrap the print in tissue paper and place between two 'Canine Boards' so that the paper doesn't buckle when drying.
14. Remember to clean off any smudges that you may have left on the press so that you don't end up with random ink lines on any future prints.
15. Once you've finished you can clean your etching plate using ordinary cooking oil.

How to prepare a spent etching bath for recycling  

(keep in mind that the bath tray can be used multiple times):

1. Add hot water to the bath to re-dissolve any solid sulfate particles and stir.
2. Add a pile of metal off-cuts (Aluminium, zinc or steel) to the tray.
3. Leave to act overnight.
4. On the following day, drain off the liquid into a bucket and add sodium carbonate (about two or three cups per bucket).
5. Once fizzing stops the liquid can be discarded.
6. The remaining solids can now be left to dry out. Keep in labeled, sealed containers and then treat as dry waste.