Borosilicate screens are similar to Ultra Fine screens in every way, except the glass they are made on. Borosilicate glass is the same type of glass used in pyrex products and other products that require heat and impact resistant glass. This glass is more expensive than regular soda-lime glass, and much more difficult to cut, so the price is double that of a soda-lime screen, but the result may be well worth it. Borosilicate glass is much stronger than soda lime screens and we do not know of any broken borosilicate screens in two years of making them.
Borosilicate glass also opens new horizons for backpackers and others looking for a ultra light weight camera. In colaberation with Nicholas Nixon, we developed an ultra-thin 1.1mm screen for his 8×10 camera. For your referance, that is a little thicker than a credit card! We also created a single 1.5mm screen for his 11×14. Of course, this ultra thin glass is not for the faint of heart.
Borosilicate screens offer a slight advantage in clarity over regular screens –on the order of a couple percent. Some really discerning customers buy borosilicate just for the extra clarity, although it is difficult to tell the difference by eye.
Hello,
I’m interested in getting a replacement ground glass for my MPP Micro Technical Mk VIII. I’m very new to 4×5 photography (but have done a lot of 35mm & MF photography and darkroom work with those formats. I just got the MPP and the ground glass is in 2 parts: a very thin ground glass and a thicker fresnel glass (really plastic). There are two spring-steel metal hold-down brackets that are held down by two screws each and have two “fingers” that hold the glass down. These brackets currently sit on two metal spacers that seem to be required because of the thickness of the fresel “glass”, but if I remove the spacers and the fresnel, the brackets don’t hold the ground glass down tight, because it’s so thin. I think I want a slightly thicker ground glass and no fresnel, but I’m not really sure, so I wanted your opinion and advice. I WILL get it from you, if you can tell me what I need. The ground glass is 101.6mm tall (there’s 102.4mm vertical clearance between the locator screws on the top and bottom of the graflok holder back), and 124.9mm wide )with a mm or so of “slop” in the fit between the hold-down brackets side-to-side – meaning that I think a 126 mm wide glass would fit perfectly). The ground glass is 1.55 mm thick.
The fresnel “glass” is 95mm tall and 120mm wide, but it has 4 “ears” that fit under the “fingers” of the hold-down brackets. It’s 2.45mm thick.
The spacers are 2.34mm thick. Since the combination of the two is 4mm thick, it seems that a ground glass 1.8mm to 2.0mm thick would fit snugly, but I’m mostly guessing on that…
Sorry for all the detail, but I don’t understand why there’s two pieces, in the first place, or whether they’re standard or not. I seriously doubt the ground glass is original because its edges are pretty rough and razor sharp. In any case, they both have to be replaced because they’re very scratched on both sides. I’m guessing I just need a single piece of ground glass the correct thickness. I’d like to get it with lines, I think, because I plan to use it with 4×5, 3.25×4.25 and 6×9 backs, and that would help me have some reference points for the other formats.
So, now that I’ve bored you to death with my problems, would your standard or borosilicate screens be the solution?
Thanks for your help,
Mark Chalkley
Hi,
I have a Shen Hao 4×5. I am interested in purchasing one of your borosilicate screens for it.
Regards,
Lou