Rohrer & Klingner*Since 1892* dokumentus Black Document Ink, 50ml Bottle

Been looking for a good, reliable, permanent black, registrar's ink for a while. This fits the bill perfectly. It is expensive, but is excellent ink - very solid black, thick, but flows nicely in an ordinary fountain pen without clogging or drying. I have been using it every day for the last 10 weeks to record Met Office daily observations, including on sunshine recorder cards which are outside in all weathers for 24 hours at a time. The ink stays perfectly on the paper even when the card itself is disintegrating in the wet. I also use it to register marriages, baptisms etc in an official capacity, and it does not run on any of the paper types on which I have tried it. Whether it is still as dark and legible after a hundred years or more remains to be seen...It loses a star because the instructions give no indication that the pen needs to be washed thoroughly before first using the ink. I guess this is a fibre-based ink, but in any case it reacts with traces of other ink that might have been previously used in the pen, and congeals on contact. My pen had previously held a different registrar's ink, and although it was empty it had not been washed out. Consequently I was horrified to find the pen completely clogged up when this ink was first filled. It took around half an hour taking it peices and washing, picking lumps of ink out with a pin, and drying each part separately, then reassembling, before refilling to find it flowing nicely, and me mightily relieved at not having wasted a lot of money on a jar of useless ink!

It's good ink

This ink has clogged up every fountain pen I own. From £10 to £650. Push cap or screw cap. All of which had document grade ink with no issues before. I am using it with a dip pen now.