Nowadays the modern pen comes complete with ink in capsules, but till the late 1800’s anyone using a pen needed to continuously dip their pen nib in the ink as they wrote.
These inks were made solely from natural materials such as bark, berries etc., which would produce different coloured pigments that could then be used to produce a coloured ink. In the case of green ink it is made from the chlorophyll in leaves.
To make green ink you will require 1/2 cup of green leaves, blender, 1/2 tsp salt, 1/2 tsp white vinegar, a strainer, a bowl and some small bottles with tight fitting caps.
To make the green ink use the method below
1. Place the leaves in the blender
2. Pulse the leaves till they form a pulpy liquid
3. Strain the pulpy liquid into the bowl
4 Add the 1/2 tsp white vinegar and the 1/2 tsp salt to the strained liquid
5. Stir the mixture till the salt has completely dissolved
6. Pour completed ink into the small bottles and seal with the tight fitting lids.
Note: The addition of the vinegar and salt will stop the ink turning brown
Since this ink is made for use with quill pens, I think it should work with a dip pen, but I don’t think it will be a suitable ink for use in fountain pens (use at your own risk).