Advanced daylight tank for sheet film - survey

[rcmartins]

If it does indeed avoid the bromide deposition I would too. A tray could do it if it allowed for the emulsion side to be placed facing downwards without scratching. I believe a tray with lateral rails could do the trick.
Anyway, I would buy it, yes. After having tried the yankee tank, the nikor tank, the modified orbit and simple trays, I have chosen the yankee tank as the best for my semi-stand procedure, but have always been disturbed by the 1,65 l it requires.
raul

[Regular Rod]

In the intrest of doing market research, I have a design in mind and on paper for a sheet developing system. I am want to determine if it would be worth my effort to proceed to the next step, so I am asking for your input.

Here is the gist of how it would work:
1. It would be a tray system of sorts, allowing the user to agitate their film by rocking the system much like tray processing for developing paper.
2. You would be able to develop up to 10 sheets (of 4x5, less for 5x7 and 8x10) at a time and as few as one.
4. All 10 sheets would remain separate from each other. No sheet of film would touch another sheet of film.
3. It would be light tight as soon as it is loaded with film and properly sealed. It would remain light tight through the entire process, so it would be considered a daylight tank.
4. You could process all 10 sheets of film for different time intervals, so it would be fully zone system reedy.
5. Would use no more than a liter of developer per development.
6. Extreme ease of use. It would be easier to load than your standard film holder
7. *only a slight possibility* it would be temperature controlled. This would probably add significantly to the cost.

I would start this unit with a price-point of about $80.

My question then becomes, would enough people want one? If it were you and you saw a system like I described would you likely pay $80 for it?

Yes if it can be used for semi-stand and stand development. How will it do different times for ten sheets?

Will it be like a better version of this http://freepdfhosting.com/f640343f29.pdf ?

RR

[Regular Rod]

Since you say it will be akin to a tray I am guessing it won't be particularly suited for standing or semi-standing development. The problem I have with the patterson orbital, which I am guessing is similar to your design, is the bromide deposition. Vertical tanks, on the other hand seem to waste too much chemicals.
raul

What is this problem?

RR

[Regular Rod]

It should be suitable for stand development, but that I can honestly say that is a technique I am not perfectly familiar with.

I should note, that I have yet to see anything, current or past, that approximates this design. The best I can describe it would be souped-up tray processing. My next step is cost analysis. Again this idea is still a long way off, but it is something I am pretty excited about. I just wish I thought of it 30 year is ago when sheet film was all the rage!

Tray is perfect for stand and semi-stand development so your system should be okay.

RR

[Scotty230358]

I would certainly be interested. My Jobo Expert tank is the easiest tank to load I have, my Jobo 25 is harder to load and uses nearly 1500cc of chemicals but it can be used for inversion agitation which is the development method I am most used to. Just one question - do you think your device can be used for intermittent agitation or would constant agitation be the only practicable method.

[brucep]

Put me down for a 5x7 and a 10x8

[Len Middleton]

Jeff,

It sounds intriguing, and sounds like you understand a number of the potential issues.

Would be interested in your progress, and at $80 it would be easy to finance through the selling of a used Jobo Expert tank if it proves to be better.

You still have the issue of converting market research into some understanding of what the market actually might be. That will of course impact projected volume and affect your manufacturing processes (small volume prototyping, versus mass production).

Good luck with it and keep us posted. And for $80 for a 4x5 or an 8x10, it is worth the investment to me.

Hope that helps,

Len

[koh303]

My design would be daylight safe and assuming it is used correctly, fool proof for getting unscratched, evenly developed negs.

Can you offer some more insight on how this will work? how can you can have different times for different sheets? if it is fool proof, why do you need to assume it will be used correctly?
How will the sheets be held in a way that prevents flow marks or patterns?
If you use only 1 sheet do you still need a full 1 liter of liquid?
This sounds like a great concept, with the list of things it could do, and a great price point i wish you good luck in bringing this to market, though its hard to see how this will be achieved, regardless of price.

[Bob Salomon]

Back in the 70s a fellow named Sam Needleman along with a camera stow owner named Bobby Olden came up with a daylight print processing system called the Agnecolor processor that was marketed by EPOI. It was an inclined plane which washed chemistry over the print. Your description kind of reminds me of the basic model modified for film rather then prints.

They marketed the technique as a "Laminar Flow" process.

[rcmartins]

While developing the exposed silver bromide crystals in the film emulsion are converted to free silver and a bromide ion. The free silver remains in the emulsion (later removed by the fixer) and the bromide is released to the developer. As far as I know, but I am not a chemist, the bromide ion will affect the developer since it is a restrainer and I believe it is the reason why potassium bromide is added to a developer, to avoid chemical fogging. If the released bromide stays on top of the emulsion it will affect development and improper agitation, either too much or insuficient, will give rise to trails of uneven development which I am guessing are called bromide drag patterns.
I am not absolutely sure about this. As I said, I am not a chemist. But my experience is that indeed tray development with stand development, at least the way that I do it, gives very distinct patterns of uneven development that I do not get when the emulsion is vertical.
I would very much appreciate if someone really knowledgeable on this topic could provide a more solid explanation to the chemical roots of uneven development and its relation to agitation and orientation in development tanks.
raul

What is this problem?

RR