All the Etching Acid Recipes below are a guide only, and you use at your own risk. Please take all health and safety and precautions and wear protective clothing.
Etching Acid Recipes
Acid – Nitric Acid comes as 70% strength. This is extremely harmful and must be used with caution.
The gases that come from this acid are very harmful so wear a mask and full protective health and safety gear. Always mix the acid into the water and not the other way around. Always decant the acid at the end of the day and always use an extractor unit to work with this acid. Test plates are advisable for both line and tone for any of the acids or plate making mordants.
| Metal | Nitric Acid | How to mix |
| Copper Strong | 2 Water to 1 Nitric Acid | 2 Parts Water first then 1 part Nitric Acid second |
| Copper Weak Mix | 3 Water to 1 Nitric Acid | 3 Parts Water first then 1 part Nitric Acid second |
| Steel Strong Mix | 5 Water to 1 Nitric Acid | 5 Parts Water first then 1 part Nitric Acid second |
| Steel Weak Mix | 8 Water to 1 Nitric Acid | 8 Parts Water first then 1 part Nitric Acid second |
| Zinc strong | 10 Water to 1 Nitric Acid | 10 Parts Water first then 1 part Nitric Acid second |
| Zinc Weak | 18 Water to 1 Nitric Acid | 18 Parts Water first then 1 part Nitric Acid second |
| Use Extractor unit and all safety precautions. Use at own risk. Mask, gloves and extractor unit etc… | Neat Acid for Spit Biting – always mix with a little water to get it etching and then paint onto your plate. | If you would like to get rid of this solution do NOT tip down the sink. Take to your local tip and they will advise you on how to get rid of the liquid. |
Etching Acid Recipes
Mordant – Saline Solution, Copper Sulphate and Salt mix
This is a great Non-Toxic Mordant to use. Wear a mask when mixing the Copper Sulphate with the Salt. Always wear gloves even thought its Non-Toxic
Just remember that this mordant likes to bite line well but when it comes to etching tone it can undercut the aquatint very easily so if the plate is left in to long, or the grade of metal is weak, it might etch your tones to much. Always use caution. Test plates are always advisable for both line and tone for any of the acids or plate making mordants. Wear a mask when mixing but this is the most Non-Toxic mordant
| Metal | Saline Solution – Copper Sulphate and Salt | How to Mix | |
| Steel, Zinc, Aluminium and stainless steel (Same mix for all) | 10 litres of Tap Water, 500g Copper Sulphate 125g of Sodium Chloride (table salt) (or a stronger mix but will give you less control over tone)
Or a very strong mix 200g Salt & 200g of Copper Sulphate with 1 litre of hot water |
Put the Water into the mordant tray, add the salt and dissolve. Once dissolved add to the copper sulphate. Once it has all mixed together it is ready to use.OrAdd the Salt and Copper Sulphate together with 1 litre of hot water, let it dissolve and mix together then add another 1 litre of water and its ready to use. |
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| Use a mask and gloves when mixing but once its mixed it is classed as Non-Toxic so still wear gloves but a extractor unit is not necessary. Use at own risk. | To rejuvenate this mordant you can add 100g of Salt and 100g of copper sulphate together mixed with half a litre of water. Add this to the bath of Saline solution and this will keep it going for longer. | If you would like to get rid of this solution, leave in open air in a tray, it will over a few weeks turn into powder that you can throw in the bin. Or take to your local tip and they will advise you on how to get rid of the liquid. |
Etching Acid Recipes
Acid – Ferric Chloride
This is the old way of etching plates before Edinburgh Etch was invented where citric acid is added to the mix to help you etch plates the right way up so you can see the etch in process. Full health and safety gear needed including an acid extractor unit and masks and gloves.
| Metal | Ferric Chloride 42°- 48° Baume’ Density | How to Mix |
| Aluminium | 1 litre Ferric Chloride 45° Baume’ to 4 litres of water | Mix one to the other and wear protective gloves and mask |
| Copper Bras and Zinc | Three strengths 1. 33° Be’ (fast) 2. 35° Be’ (fairly fast) 3. 45° Be’ (slow) | Use Extractor unit and all all safety precautions. Use at own risk |
| Use Extractor unit and all safety precautions. Use at own risk. Mask, gloves and extractor unit etc… | Note there is no citric acid so you need to bite the plates face down and agitate the bath frequently. | If you would like to get rid of this solution do NOT tip down the sink. Take to your local tip and they will advise you on how to get rid of the liquid. |
Etching Acid Recipes
Acid – Copper Sulphate Powder.
This is a good way of working with Steel, Zinc and Aluminium. Nitric acid is also a good way to work with these metals. Copper Sulphate powder is probably a little bit more user friendly though. Always use caution. Test plates are always advisable for both line and tone for any of the acids or plate making mordants.
| Metal | Copper Sulphate Powder | How to Mix |
| Steel Zinc and Aluminium strong | 100g Copper Sulphate powder to 1 litre of Water | Mix one to the other and wear protective gloves and mask |
| Steel Zinc and Aluminium weak | 50g Copper Sulphate powder to 1 litre of Water | Mix one to the other and wear protective gloves and mask |
| Use Extractor unit and all safety precautions. Use at own risk. Mask, gloves and extractor unit etc… | If you would like to get rid of this solution do NOT tip down the sink. Take to your local tip and they will advise you on how to get rid of the liquid. |
Etching Acid Recipes
Acid – Edinburgh Etch (Ferric Chloride and Citric acid)
This is a very popular way of working with both copper and steel. Always mix a separate bath for each metal. Always use caution. Test plates are always advisable for both line and tone for any of the acids or plate making mordants.
| Metal | Edinburgh Etch | How to Mix |
| Copper and Steel | 250 grams citric acid dissolved in 750 ml of warm water + to 4 litres of ferric chloride | dissolve the citric acid in the warm water and then once dissolved add to the 4 litres of ferric chloride |
| Use Extractor unit and all safety precautions. Use at own risk. Mask, gloves and extractor unit etc… | If you would like to get rid of this solution do NOT tip down the sink. Take to your local tip and they will advise you on how to get rid of the liquid. |