Borosilicate ground glass screens?

[Kirk Gittings]

The wind today at the Bisti won a battle with me and my camera. Of course I didn't have my spare with me which is highly unusual. Time to look at replacements. Anyone here have any experience with Steve Hopf's Borosilicate screens?

[RSalles]

Kirk,

I have, and highly recommend you. Maybe it's also a good idea for you to get + one as spare, never know,

Cheers,

Renato

[David Karp]

I have one too. Excellent. It is not a bright screen. Just groundglass. I had him put a silver grid on mine. You can see it when you need it. It sort of disappears when you are not looking for it. Steve is easy to deal with and quite responsive in my experience.

[pjd]

I've got one, the borosilicate is good - and beyond that Steve is definitely a decent guy to deal with. I messed up the details of an order once, and he did a lot more than I expected to help me out.

[RichardRitter]

Borosilicate is 3 to 6 % brighter then regular soda lime ground glass.

The bad side of brosilicate is it harder and breaks a lot easier.

[Kirk Gittings]

Borosilicate is 3 to 6 % brighter then regular soda lime ground glass.

The bad side of brosilicate is it harder and breaks a lot easier.

Darn, I thought it was less prone to breakage.

[Paul Cunningham]

Darn, I thought it was less prone to breakage.

Me too. If it is indeed the glass of Pyrex, it has a lower expansion coefficient, which is why it is good for hot materials. I think a previous poster mentioned that a thin(ner) version is used for ground glass, which makes it more fragile in practice, (but perhaps not in theory).

[HMG]

Me too. If it is indeed the glass of Pyrex, it has a lower expansion coefficient, which is why it is good for hot materials. I think a previous poster mentioned that a thin(ner) version is used for ground glass, which makes it more fragile in practice, (but perhaps not in theory).

Actually, Pyrex used to be made with borosilicate glass, which did provide great thermal properties. Now it's made with tempered glass which has poorer thermal properties, supposedly slightly better resistance to breakage, and is cheaper to produce.

[Jim Graves]

Borosilicate is 3 to 6 % brighter then regular soda lime ground glass.

The bad side of brosilicate is it harder and breaks a lot easier.

I'd be interested in seeing the source of this opinion.

[RichardRitter]

I'd be interested in seeing the source of this opinion.

Just look up the transmission rate of each type of glass. Bososilcate is about 99% which is about the same of optical grade glass. Soda lime is 96% or less it's window glass if you look at the edge of the glass it will see a blue /green color to it. Not good for UV printing acts as a ND filter.