Graflex.org

[t.r.sanford]

Guide numbers work very well, once you get the right one for the particular flashbulb, reflector type and film you want to use.

When flashbulbs were in flower, there were a couple of interesting widgets on the market that combined a rangefinder with a flash calculator. I don't remember ever seeing or hearing about them, but I did not travel in high-end circles! The outfit that sold the immortal "Norwood Super Director" light meter made such a widget, and I got one from eBay a couple of years ago. It is a strange-looking thing, with a wonderful calculator dial that looks as though it had been designed by Leonardo da Vinci, and which is completely incomprehensible!

Doing the division in one's head is a whole lot more straightforward, but if you want a real conversation piece, you might look out for one of these gizmos.

[JoePhoto]

Around 1980 one of the photo magazines I bought had instructions for pushing Tri-X to ASA 64000 <3 zeros intended>. I tried it once for a demolition derby with 35mm and it worked well. I've long since lost the instructions and haven't been able to find them but they involved using Edwol FG-7 as a developer and then "steaming" the film over regular buy-at-the-drugstore hydrogen peroxide then stopping and fixing as usual. The steaming I did was in a tank with about 1 inch of peroxide and an empty spool at the bottom to keep the film reel out of the peroxide. I don't know how I would do this with 4x5 and the FP tank that I use.

_________________
If the best can't be had let the worst continue....

[t.r.sanford]

In the old days, "hypersensitization" was used before the exposure, and/or "latensification" was used afterwards. I think the astronomical fraternity nowadays is using hydrogen as a hypersensitizing agent; ammonia or mercury once were popular. Latensification could involve a predevelopment bath, or a weak "flash" exposure.

I'm fascinated by the process you describe, since it involves treating the film after development. I had not heard of this before, and would be very glad to know how it's done.
I suppose the fuming would most efficiently be done with the film in hangers, and a deep tank.

[Les]

This process was discussed in one of my college classes. If I recall correctly it helped if you used a higher strength of H2O2 but concentrations higher than about 5% when combined with a soluable metal (silver) could create Hydrosene gas... one of the better rocket fuels.

TR, tell me more about your guide number widget. Did it calculate a guide number or did it move the aperture ring for you?

Les


[ This Message was edited by: Les on 2004-08-16 08:36 ]

[t.r.sanford]

I don't have the device in front of me as I write but, in broad outline, it is a vertical, uncoupled rangefinder (with an accessory foot) that has a large and complicated dial at one end. It does not couple to the camera controls.

When you mount the thing vertically in an accessory shoe, the dial is at the top, supported by a gracefully curved metal element that gives it a kind of art-nouveau aspect. As an optical instrument, it is nothing to write home about, but it's usable.

After turning the dial to bring the images into coincidence, you can read out the correct aperture for various combinations of flashbulb and filmspeed. Unfortunately, you do this by following series of curved intersecting lines, and I haven't yet had the time to figure it out.

There seem to have been a couple of these devices offered in the '50s, but I was reading the photo magazines and hanging out in camera stores with adolescent enthusiasm and determination back then, and I don't recollect ever reading about or seeing one.

[alecj]

I've got an advertisement for such a gadget called an HCE Focoflash, offered in the late 40s - early 50s. It sat on the bed of the camera and, through a mechanical adjustment, moved the fstop lever as the camera was focused. Real American ingenuity.

[Lensman]

Photos and descriptions of the Norwood 'Flashrite - that is the correct name - and the HCE Focoflash may be seen at Rick Oleson's web site http://tinyurl.com/469bq
I submitted the literature -which I got from the manufacturer in the '50's as I recall- for the Focoflash which was designed for 4X5 Pacemaker Graphics & Crowns with 127mm lens. It may or may not ever have been sold. It states other models to follow, but I never saw an advertisement for it. HCE also manufactured Lenshoods and possibly filters. They were in SanFrancisco.

[Dan Fromm]

[Les]

re: Focoflash. I'm not sure if they ever built any more, but they did make at least one model.

And you're right, this thing is incredibly complicated, more complicated than the telephone, I wonder if Don Ameche invented this too! (If you're smiling you're over 40 )

[t.r.sanford]

My "Norwood" flash RF/calculator is very, very similar to the one pictured, but has an accessory foot in place of the lanyard lug at the bottom. Just the thing to adorn your "Exakta VX"...

The device for attachment to the "Graphic" focusing mechanism is very cool indeed, but if you had a 135mm. lens, you were out of luck, I suppose.

[Les]

Well....... I'm not going to go into the math but I suspect if you tweaked it a little so the error is across the board instead of just at one end, then set the ASA about a stop lower, you'd end up with printable, if not consistant negatives.

Les

[glennfromwy]

Looks like Rube Goldberg has been at work. Is that thing steam powered?

_________________
Glenn

"Wyoming - Where everybody is somebody else's weirdo"

[disemjg]

If one of you wants a Norwood Flashrite there is one FS at RITZCAM.com for the magnificent sum of $12, in box. A weird device, but not in the same leauge as that contraption that Les posted the photo of.

[Sjixxxy]

[Lensman]