Art & Craft idea
Modern inks have the advantage of intensity, colour fastness and flow, but don’t let that stop you from making and trying out your own from natural materials. This is also a good educational activity if you are looking for something to do on early history.
Think about using crushed berries or walnut husk (not the nut, but the green covering of tree picked walnuts) mixed with a little water or vegetable oil. If a pestle and mortar is handy you might be able to use this to grind your ingredients down finely and you may need to strain any results to get rid of fine particles.
If you are experimenting with your own inks, do not try them with modern pens as you are likely to damage the pen or at the very least clog it up. Think about using a fine brush or piece of wood whittled to the shape at the end (pointed if you want a thin line or flat blade for a more calligraphic style). You can also easily make quill pens from old feathers. You’ll need a relatively large feather and the knack is to cut the tip of the quill of the feather off at an angle with a sharp knife to leave a flat blade to write with.
If you want more detailed instructions on how to cut your own quill pen there are some detailed steps on Regia Anglorum https://regia.org/research/church/quill2.htm