Copyright 2006, 2007, 2008 Marcus Newhall
Sklo Union: An Iridised Oddity
| In February 2007, I purchased a plate which I recognised as being from a range, made at the Rosice factory of Sklo Union, and designed by Jírí Brabec, around 1980. | |
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| The "wood-grain" plate was of particular interest as it is iridised. As this is not a common treatment for Sklo Union items, I contacted Glen Thistlewood, the highly respected English authority on iridised and Carnival glass, to ask if this was a treatment she recognised. The iridising is applied to the base of the plate, the upper surface being un-treated. Being no expert on iridising techniques and technology, I had no idea, whether this iridising had been applied whilst the plate was still hot, or indeed, whether it was possible to iridise just one surface.
Glen immediately had her suspicions that this was not a stannous salts iridising, (hot treatment), based on the pre-dominantly blue and green colour, and suggested that what we are looking at here is post-production iridising, using a process known as "low-vacuum iridising". The pertinent questions were: Is there any loss of the iridised coating? If so, is there a base-coat which shows through? If so, what is that colour? As the image above shows, there is loss of the iridised coating, and the base-coat is a pink-silver metallic colour. With these answers, Glen was able to suggest that this plate was probably iridised by a German company LGW, Lleinauer Glaswaren, (see Glen's article here) who appear to have specialised in "e;low-vacuum iridising", from the 1940s until the late 1980s, and who are known to have purchased blanks from several major European glass manufacturers. It has been difficult to trace particular items back to the specific manufacturers, but in this case, we clearly have a Brabec 5214/270 plate for Rosice. It is also the case that I have seen other, clearly identifiable, Sklo Union items showing this treatment, including a Rudolf Jurnikl ( Rudolfova huť ) ash-tray, from the early 1960s, iridised in a similar manner. |
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Another image of the plate. |
Detail of the base of the plate. |
| Obviously, the discovery of these items is important, but there are notes of caution. The first is that though these items are very probably iridised by LGW, this does not preclude the possibility of such a process having been trialed in Czechoslovakia. I am awaiting a response from Professor Novotny, of the Liberec Technical University, regarding the use of "low-vacuum" iridising in Czechoslovakia during the 1970s and 1980s. Both Glen and I are aware that there is at least one company in the region offering "low-vacuum" iridising, but their technique involves the use of titanium, and is therefore not the same process.
The second is that as the process can be used long after the original production of the blank item, then technically it would be possible to iridise items, to give an appearance of rarity, when the converse may be true, that the item could be considered not to be an authentic Sklo Union production, possibly even vandalised. My thanks go to Maxeen Kimber for her logistical organisation and support, and naturally to Glen Thistlewood for her generously shared information regarding LGW and the technical knowledge regarding this iridised plate. Article © Marcus Newhall 2007 Images © Marcus Newhall 2007 Back to previous page or go to the Top of this page |
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