Fancy writing on dark coloured paper/envelopes in white?
This highly raved "Bleed Proof White" is your to-go-to white ink. Even the hairlines produced using the pointed pen (aka dip pen) are opaque white! Works beautifully with a water brush too!
Comes in a paste like texture and will require you to mix it up with some water to get the right consistency -slightly viscous and not too watery. Apply it to the back (or front) of your calligraphy nib and go!