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Glass Identification - Post here for all ID requests => Glass => Topic started by: catshome on August 17, 2006, 03:42:31 PM

Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: catshome on August 17, 2006, 03:42:31 PM
Hi - Just wondered if anyone had any tips for telling the difference between cobalt, bristol and irish blue glass................and any other types I may not have got confused by yet.  I would post a photograph but it's so hard to tell the actual colour of "blue" glass from a picture.  The bowl I have is a lovely purple/blue colour.  I don't think it's anything special but it got me looking at blue glass...........hence the confusion!

Many thanks
Cat
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: David E on August 17, 2006, 05:01:54 PM
Hi Cat,

Not sure whether this is helpful, but whenever I photo Bristol Blue it always appears with a purplish tinge. This could just be my camera of course :roll:
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: Pinkspoons on August 17, 2006, 05:08:04 PM
Holmegaard's deep blue of the 50s-70s also has a purple tint to it. It might be common to a lot of dark blue glass, I don't know as I only have Holmegaard pieces to work from.

Edit: That should read 30s-70s. The deep blue of the 1820s-1920s was brighter and lighter, from the pieces I've owned and seen.
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: David E on August 17, 2006, 05:12:16 PM
The story goes that the glassworks owner would throw a gold sovereign into every fresh pot of glass to give it the distinctive Bristol Blue hue.

Here's a link that might help:

http://www.bristol-glass.co.uk/
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: catshome on August 17, 2006, 06:00:38 PM
Thank you all.

Nic - I was very interested to hear that Holmegaard had made blue glass with a purple tint..............I'm particularly drawn to Scandinavian glass that's why I bought this - it's very simple (quite heavy).  I posted a couple of photos as you might have seen something like it yourself.  Still amazed I can't get it to photograph the colour it actually is!

http://glassgallery.yobunny.org.uk/albums/userpics/smallerDSCN1186.jpg

the bottom is :

http://glassgallery.yobunny.org.uk/albums/userpics/smallerDSCN1190.jpg

I'm off to check out the bristol glass site.

Thanks again
Cat
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: Pinkspoons on August 17, 2006, 06:12:50 PM
Hi.

It's a very nice and simple piece, but unfortunately not one I recognise from anywhere. It's not Holmegaard, though. I can say that with relative certainty.
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: catshome on August 17, 2006, 06:14:49 PM
Thank you for taking a peek...........it is rather nice and so much better in the "flesh"!  Cat
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: Pinkspoons on August 17, 2006, 06:23:00 PM
Just for colour reference, here's a Holmegaard jug dating from 1950. The purple tint doesn't show up too well, unfortunately...

(http://i18.photobucket.com/albums/b108/pinkspoons/holmegaard-jug1.jpg)
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: catshome on August 17, 2006, 06:30:47 PM
Hi again Nic,

At the risk of this turning into a mutual admiration society.............NICE JUG!  I like the way the foot "lifts" the body of the jug - it looks more squat than I would have expected - is it distorted in the photograph?

I just realised that the halo on the white surface under the jug is the same colour as I had on the paper I put under my bowl - you can really see the purple there.  Funny how it doesn't photograph though.

Cat
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: Lustrousstone on August 17, 2006, 06:31:04 PM
According to our friend Ivo (Glass fact file a-z), Bristol blue is so called because the colorant, zaffre (containing cobalt oxide), was produced in or imported through Bristol (1760-90 and 1820-40). It is a greenish blue to dark blue lead glass. So it is a cobalt blue, but you pays your money and choses your shade :lol:
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: catshome on August 17, 2006, 06:35:38 PM
So Bristol Blue and Cobalt are basically the same thing?  But if the pigment range is greenish blue to dark blue, does that include deep purple blue or should I be looking for something else to call it?
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: Lustrousstone on August 17, 2006, 06:38:56 PM
Blue :lol:  I don't know. I was just saying what Ivo says in his book. It's all very subjective really. Your blue is probably cobalt based, but the exact shade would depend on what else is in there
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: Pinkspoons on August 17, 2006, 06:43:02 PM
Quote from: "catshome"
...it looks more squat than I would have expected - is it distorted in the photograph?


No, it is that squat in real life. It's a tiny-tiny cream jug, about 2-inches tall.
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: catshome on August 17, 2006, 06:46:19 PM
Nic - I have to thank you I really needed a good laugh and that did it for me!  It looked like a pitcher................2 inches tall   :lol: Cat
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: Pinkspoons on August 17, 2006, 06:51:21 PM
I like that photo because it does make it look like a quite large and heavy pitcher at first glance... the paper label on the side is a bit of a give-away for its scale, though.  :lol:
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: catshome on August 17, 2006, 06:53:14 PM
only if you know how big the paper label is!
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: David E on August 17, 2006, 07:04:32 PM
I was under the impression Bristol had a certain amount of gold chloride included, whereas Cobalt didn't?

Cat, the site I gave you has changed. It used to give some fascinating detail on the origins of the colours Bristol Blue/Green and Ruby, but this seems to have disappeared :(
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: catshome on August 17, 2006, 07:11:34 PM
Hello David,

It was still interesting to me as I thought ALL Bristol Blue glass was old...............for some reason I thought they had stopped production of THE actual "Bristol Blue".

The technical stuff about the colour and content of the glass is also interesting but a little hard to apply without a chemistry set and perhaps a scanning electron microscope??

By the way...........I bought 2 pieces of REAL Chance glass today and I didn't even need to email you to check............all your training is paying off..............now hurry up with the book so we can all be millionaires!

Kind regards
Cat
Title: Identifying Blue glass..........Bristol, Cobalt, Irish?
Post by: Lustrousstone on August 17, 2006, 07:21:53 PM
I think perhaps you're right Cat. Hence the dates in Ivo's book. I also suspect it's evolved to become a colour. Modern Bristol Blue glass is just that. Blue glass made in Bristol