The thought of processing sheet film by inspection is very appealing and makes perfect sense. Many do it with a dark green safelight but some, I understand, use an infrered light source with infrared goggles to "see" the film thru the entire process as opposed to the few seconds a green safelight can offer.
Question is, what is the cost of an appropriate infrared system and where does one get such a thing?
Regards.
A pair of Gen-I (generation 1, the oldest technology) IR goggles will cost about $500 and can be found (among many other places) here. I have a pair that will focus down to about 12 inches, which should be good enough. You will need to have an IR source in a totally black darkroom. The goggles come with an IR source mounted on them you can use. However, these sources give off a faint amount of visibile light way down in the red region. (You can see this with the lights off and the IR source on.) So, I would recommend getting a separate IR source to use. You can get one cheaply from some place like here.
Take a look at nightvisionmall.com, too. I had the same idea you have, but in my not-very-thorough investigation I discovered that many of these devices don't focus close enough to be of any use for developement by inspection.
Hi Dan. I'm thinking along the same lines. I've seen googgles on ebay for a few hundred dollars, and IR lightsources for around $30. I'm thinking of making an IR light table, and developing my film in glass trays on top of it, using Jorge's brush technique. I haven't found a better technique to guarantee perfectly even development. IR goggles would also be very useful for loading film holders, cutting down bulk film, loading reels etc. Worth the investment, I think.
This makes me wonder: what do you see if you look at a processed film by transmitted infrared light? Or reflected light? Does the depositied silver stop the IR, or simply pass it just like the substrate (IOW, would you be able to see what you're inspecting?) For that matter, how well does the base material pass IR? I suppose the film base is probably transparent to IR, but??? So many toys, so little time......
I have done some press work with a horizontal process camera and ortho film under a red safelight. Back in the days when halftone dots were all the rage in offset lithography.
Perhaps before spending the big bucks on IR, you could run some experiments with Ilford Ortho film and the appropriate safelight. Unlike the litho film I was using, this film can easily be developed to pictorial contrast.
Here’s Ilford’s pdf:
http://www.ilford.com/html/us_english/pdf/ortho_plus.pdf
One lab I worked in had a homemade fiberglass-over-wood sink with a small clear area, under which was a red safelight. We developed the film in a pyrex glass cake pan set on top of this lighted area. The film being backlit, we could still-develop by inspection. Never had to touch the film. Worked great.
But be careful of fogging this film.
Steve,
Just a minor point: IR filters don't stop IR light transmission - they allow only IR light to be transmitted (i.e. they filter out all light except IR).
Cheers, Graeme
Mr. Cook, that's exactly what I have in mind, except substituting an IR source for the red safelight. It's good to know that I'm on the right track. Thanks!
What to look for when developing by inspection with an IR light? Does not seem to matter which side. When I saw film through an IR light it looked like it was on a light table. Admittedly, this was already developed film, but I suspect it would be the same while actually developing it.
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