Tula (or niello) is an alloy made of silver, lead and copper adding a certain amount of sulphur. This mixture creates the typical greyish-black coloration. Tula's melting point (approximately 500 °C) is significantly below that of silver at 800 °C. In order to bring the Tula on to the silver, a pattern must be etched, engraved or cut out of the workpiece leaving gaps. Using a open flame or an oven, these gaps are then filled with the melted Tula. Obviously this process is very difficult when decorating the round sleeve of a fountain pen as the liquid Tula inclines to flow out of the gaps.
As fountain pens with practically the same decorations and coming from the hands of various producers are known to us, and since these producers could hardly have posessed the necessary know-how and experience of a gold smith to carry out this work, it is natural to assume that the overlays were done to order by a company specialising in such work even if they did not immortalise themselves with a hallmark.
On finding such a pen in a damaged state, it is natural that a collector would wish to have it repaired by an expert. However, a visit to the neighbourhood goldsmith would end in a disappointment. Since this technique is nowadays only practised in Eastern Europe (Bulgaria and Russia) to a limited extent, the local gold smith would generally refuse the work. An amateur should not seriously consider trying to repair the pen himself with substitute materials (such as cold enamel).
If a reader of this page is aware of anyone able to carry out such specialised work please inform us and we would be happy to pass on this information to interested parties.