I have done my best to try and identify with Moser exactly what the difference is between their enamels and mine (see copy of my message to Veronika and her message back to me below).
Unfortunately, I'm not entirely sure it elucidates any more on the difference in the enamelling used or the technique, although others with more knowledge (I have no understanding of this at all) may find the further info I give below helpful.
Can I just say that despite knowing this is not one of their products, Veronika and the production team have been absolutely fantastic and taken lots of time to examine my pictures and respond to me on more than one occasion
I can say -
1) Moser have said they did not make this pitcher/jug and I think they mean that they neither made the blank nor enamelled it.
2) Harrach have confirmed they made the blank and Petr Novosad went through the pattern books for hours for me and has sent me copies of the various pages as well as, I believe, evidence of who the blank was made for. I am not willing to share these but I can say it was not Moser. I will post separately on the dates later.
here is my most recent message (part only) to Veronika at Moser and their lovely response in reply -
I'm sorry to bother you again and thank you for your previous help on my pitcher or jug.
I didn't understand about your comment regarding the enamelling on the pitcher and wonder if you can help please?
What is it about the technique on the enamelling that can only be done on sodium glass please? Is it the type of enamels that are used for example?
I've been asked by a longstanding member of the Glass Message Board if I can explain and I don't know how to...
...Thank you again for any help you can give about the enamelling technique etc.
From Moser today:Thank you for your e-mail.
I asked in the production to explain me the question you require to clarify. I hope you will understand my explanationJ
The sodium glass has got the possibility of longer processing. The Italian glassworks (for example Murano glassworks) mostly use this. The advantage is that the time for decorating, sticking the ornaments and other decoration is longer and this kind of glass enable this.
The sodium potash glass which is used by Moser has got shorter time of processing. It gets faster stiff and the docarating and enameling is not possible.
Should you not understand or you might have other questions feel free to contact me-
Out of all my searches, I have am now down to only one other piece that I believe is the same hand as my pitcher/jug - it's a different shape, but instinctively I feel it was made by Harrach and
believe the enamelling house is the same one as mine. Link attached to this here http://www.rubylane.com/item/568150-2422/Bohemian-Art-Glass-Vase-10
. The jug that has the drip trails on the neck that I linked to earlier in the thread, I believe is also Harrach but the enamelling is different to mine. So this piece is the only one out of hundreds I have examined that I believe is a match to my jug for both blank and enamelling.