How to Make Indigo Ink

Make your own indigo ink.

You have to be a bit of a chemist to make indigo ink from scratch. The traditional foundation for vintage writing inks was nut gall. The oak tree produces oak apple gall. Many think that oak apples are a fruit the oak tree produces, but it's actually a malformed leaf due to a gall wasp infestation. First prepare the nut gall base or juice and then add indigo and other ingredients to it to make indigo ink.

Things You'll Need

• Oak apple galls
• Mortar and pestle
• Kitchen scale
• Sieve
• 1-gallon glass jug
• Measuring cup
• Funnel
• Rubber gloves
• Safety glasses
• Sulphate of indigo
• Iron sulphate
• Whole cloves
• Gum arabic

Instructions

1. Collect about 1 dozen oak apple galls. They develop on the branches of the oak tree where a leaf bud would normally form. In the autumn, look for them on the ground below the oak tree. They average about 2 inches in diameter.

2. Place one gall in a mortar and pestle and pulverize it into a powder. Continue until you have pulverized between 7 and 8 oz. of the gall.

3. Mix the powdered gall in 14 oz. of water. Let the gall-and-water solution sit for a few weeks until a coat of mold forms on the top of the solution. Skim off the mold and pour the solution through a sieve.

4. Pour 12 oz. of the gall solution into a clean 1-gallon, glass jug.

5. Put on rubber gloves and safety glasses and add 8 oz. of sulphate of indigo. Sulphate of indigo is a solution of powdered indigo and sulphuric acid put through a heating process. Purchase it from chemical suppliers.

6. Add 8 oz. of iron sulfate, which can be purchased from chemical suppliers.

7. Add a few whole cloves, a spice used in cooking.

8. Measure out 4 to 6 oz. of gum arabic and add it to the mixture.

9. Fill the rest of the jug up with water and let the ink solution sit for two weeks. Pour the ink through a sieve to strain out the solids.

Tips & Warnings

• When writing or drawing with the ink, it'll start out blue but will oxidize, eventually turning black.

• If your tap water has a high iron content, use distilled water.

• Don't use expensive writing or drawing instruments with this ink as it can be corrosive due to the sulfuric acid.

References

• Public Book Shelf: How Do You Make Ink?
• DJ McAdam: Study of Ink
• James Madison University: Oak Apple Gall
• Arkansas State University: Recipes for Old Drawing and Writing Inks