Interesting paper. Not being a chemist I cannot see clearly if a procedure meant for sensibilizing clear gelatin w/dichromate will also work for pigmented gelatin. But I will follow this thread with

Dear Christina Thank you so much for the coupon. I ordered the book on digital negatives and QTR. I am the happy owner your books on cyanotype and gum printing, all of them very helpful regarding

Thanks, Chris! I spent 20+ years in the book business and %30 is about as good as it gets. I'll be filling in the gaps in my library. This is great work you've done, and I'm really honored to have

Hi, I have experimented with sensitizing various photopolymerization processes (including gum) with methylene blue (red sensitive), Eosin Y (green sensitive) and fluoresceine (blue sensitive). UV

I have found the paper where the red light sensitization of dichromated gelatin is described.

No affiliation but this site seems to have a nice graph: http://photographyoftheinvisibleworld.blogspot.com/2011/01/el-nikkor-enlager-lenses-for-uv.html?m=1 It’s mostly about UV photography but it

Art: Again, according to ultravioletphotography.com, the 50mm f 2.8 transmits to 345nm, and reaches 50% transmission at 365nm. E.

Apply for price, and the statement that they will have to be refocused for different wavelength, implies for me that they will be 1: expensive, 2: just simple quartz lenses. I remember my supervisor,

I'm curios, does anyone have UV transmission data on the Nikon 50mm f2.8 Enlarger Lens 39mm mount? My searches only turned up lenses for sale. Thanks in advance. Respectfully, Art Sent from my

Hi All, The problem with a UV enlarger is not so much the UV transmission of lenses (BK7, a common optical grade glass, is reasonably UV transparent, as the El-Nikkor numbers below demonstrate), but

Oops...forgot the

They are used in microlithography (steppers) in semiconductor chip manufacturing. Here's a company that makes UV lenses - no idea how much they cost.

This from ultraviolet photography: EL-Nikkor 63: reaches 340 nm. 50% transmission at approx 365 nm. EL-Nikkor 80: reaches 320 nm. 50% transmission at approx 345 nm. EL-Nikkor 105: reaches 320 nm.

Kirk and Lawrence, Apo-El Nikkor enlarging lenses are ransparent well into the UV, but might be more expense than one would wish to spend for such a project. Best - Ed

Waaaaaaaaaaaaaay at the back of my head something is tickling a memory of special high UV transmittance lenses...for telescopes? UV Spectrometers? I wonder if one might find some lenses with high UV

For UV optics, quartz lenses would be best, but Ive never seen anything in the large sizes one would need for an enlarger. Another optical possibility would be something Mirror based, but I’ve never

Everything you say makes perfect sense. I’ve read that normal glass absorbs around 98% of UV (don’t know how true that is) but even if it’s partially true, by the time the UV has passed through

Hi, I have no experience on UV enlargers, but I tried in the past to impress some dichromated gum or gelatin by means of a dia projector, with a very strong illumination and rather long exposures (up

Mike and Dick, Always happy to learn and share knowledge- I could only share deep knowledge like this on the River Goyt, a local river to me and my home town’s industrial heritage!.. joking aside,

Dr Ware is correct, DIsodium Platinum will not print by itself. Our current research into pure platinum: Some caveats. This a release of preliminary results, it a beta release If, as the vast