No-one likes general adverts, and ours hadn't been updated for ages, so we're having a clear-out and a change round to make the new ones useful to you. These new adverts bring in a small amount to help pay for the board and keep it free for you to use, so please do use them whenever you can, Let our links help you find great books on glass or a new piece for your collection. Thank you for supporting the Board.

Author Topic: Iridisation of glass - can it occur naturally?  (Read 3067 times)

0 Members and 1 Guest are viewing this topic.

Offline Pinkspoons

  • Members
  • **
  • Posts: 3233
  • Gender: Male
    • UK
Re: Iridisation of glass - can it occur naturally?
« Reply #10 on: September 20, 2012, 11:18:24 AM »
Long-term storage in dusty places prone to condensation seems to have a knack of causing iridescence to the surface of glass - I've bought old, but ostensibly 'new', glass from closed down retailers in Italy and Denmark in the past, and iridescence was present on quite a few pieces that had been left to their own devices for 30+ years.

I assume the dust makes water in the air stick to the glass longer than it otherwise would - items in more sheltered areas were unaffected. Also, being wrapped in paper exacerbates iridescence far more than glass left in the open - presumably as a result of the paper being more absorbent than dust.

Support the Glass Message Board by finding a book via book-seek.com


Offline Lustrousstone

  • Members
  • **
  • Posts: 13623
  • Gender: Female
    • Warrington, UK
    • My Gallery
Re: Iridisation of glass - can it occur naturally?
« Reply #11 on: September 20, 2012, 11:25:45 AM »
Possibly because paper is quite acidic; acidic free paper is what conservators specify

Support the Glass Message Board by finding glass through glass-seek.com


Offline Pinkspoons

  • Members
  • **
  • Posts: 3233
  • Gender: Male
    • UK
Re: Iridisation of glass - can it occur naturally?
« Reply #12 on: September 20, 2012, 11:30:20 AM »
This would also account for it.

Support the Glass Message Board by finding a book via book-seek.com


Offline David E

  • Author
  • Members
  • ***
  • Posts: 3908
    • Heart of the Country, England
    • ChanceGlass.net
Re: Iridisation of glass - can it occur naturally?
« Reply #13 on: September 20, 2012, 12:32:57 PM »
I've seen the combination of very light iridescence and gilding in Polish tableware.
That's interesting, except it is British glass :D

Thanks Nic for that thought, which could quite possibly be the answer. Old newspaper would certainly account for this and I suspect that's what was used. The iridescence is right up to the rim, so unlikely to be a liquid so, again, the wrapping could be the reason. I can't determine whether there is iridising on the inside though - very difficult to tell.

BTW, what are the metallic salts used to iridise glass?
David
► Chance Additions ◄
The 2nd volume of the domestic glassware of Chance Brothers
Contact ► Cortex Design ◄ to order any book

Support the Glass Message Board by finding glass through glass-seek.com


Offline chopin-liszt

  • Members
  • **
  • Posts: 14462
    • Scotland, Europe.
Re: Iridisation of glass - can it occur naturally?
« Reply #14 on: September 20, 2012, 12:41:51 PM »
I would strongly suspect different metals are used for different finishes - but I know that IoWSG sprays a lustre finish on using Stannous Chloride. (Tin)
This isn't an overly mirror-like shiny surface as some are, but somewhat matt.

I've got a "Balloon" vase, which has a layer of stannous chloride sprayed inbetween casings - it gives a subtle, slightly glittery, rainbowy effect inside.

In Wedgwood Fairyland lustre, the lustre can be a gold or green shade, Carltonware used a goldy red (on Rouge Royale), Zsolnay use an eosin glaze with a gold coloured lustre.....
Cheers, Sue M. (she/her)

‘For every problem there is a solution: neat, plausible and wrong’. H.L.Mencken

Support the Glass Message Board by finding a book via book-seek.com


 

SMF spam blocked by CleanTalk
Visit the Glass Encyclopedia
link to glass encyclopedia
Visit the Online Glass Museum
link to glass museum


This website is provided by Angela Bowey, PO Box 113, Paihia 0247, New Zealand