What is Sumi
Since the beginning of traditional Japanese tattooing in the Edo period, Japanese tattooists have used ink block of calligraphy for shading.
There are many types and the quality changes greatly.
Among them, the highest grad ink block has no impurities, has a completely neutral pH value, and is harmless to the human body.
It has been 400 years so far, no one had allergic or infected by ink block. The black ink made with it is very finely grained and it will become beautiful blue-black on the skin. Producing black ink from ink block requires highest quality ink block and ink stone(Suzuri), technic and patience.
As time goes by, tattoo ink companies develop high-quality black ink, and some Japanese tattooists started use it as well, and there are changes along the times.
There is many choice which black ink use for tattoo now. But my opinion is Japanese Sumi is still one of the best quality ink.
Currently I'm based in Amsterdam so I had to stop use Japanese Sumi because of law in Europe. However I had great opportunity to make sponsorship with Kuro Sumi Tattoo Ink as Pro Team which is one of the highest quality tattoo ink company. In my opinion, Kuro Sumi Ink are blacker than Japanese Sumi and exactly same color effect.
I have responsibilities to keep tradition and also update, I think I could update about black ink with tradition.