Glazed back of enamel

[AG2012]

Hi,
This is Russian silver and enamel badge for graduation of the Imperial University faculties.
The cross is enameled (blue translucent enamel).
C clasp was repaired (replaced). Most likely hard soldered. The mystery is brown vitreous glazing on the back of the cross; it is not original because I have this badge without this feature. Normally, blue enamel would be damaged when exposed to high temperature, but it remained intact.
Therefore, back glazing has something to do with repair and soldering at high temperature, but I have never seen anything like this.
Antique enamel was sometimes done with glazed back because of non matching coefficients of thermal expansion of enamel and substrate (metal).

Jewelers use thermal resistant paste for partial covering of an object when hard soldering, but it is cleaned afterwards, unlike this brown glaze here.

Any ideas are appreciated.
Regards

[piette]

Hi AG2012,

Can you please post a photograph of the front of the brooch? As you mentioned, sometimes a counter enamel was used on the back of certain pieces during the enamelling process. I have seen a number of objects were counter enamel has been used or not used without clear reason why, for example many frames of similar design, in similar colours, some with counter enamel and some without.

I do not think there is any significant reason for this - probably largely down to the craftsman doing that piece. I would suspect that this counter enamel has always been on the back of the brooch - or maybe it has been entirely re-enamelled?

Best -
P

[AG2012]

Hi,
Thanks for the input. Not sure about re-enamelling, quite possible, but it was repaired for sure, even altered: In most variants of this badge central blue cross was attached with prongs introduced through small holes and then bent to fix the cross. This cross was soldered but there are remnants of prongs on top and bottom. Unfortunately, it`s practically impossible to find intact badge by the same maker to compare.
Regards