Ok, for those doing LF and developing with HP's Combi-Plan...
You need to pour in 32 oz of developer/stop/fixer through a roughly 1/2" hole... so it's going to take a while while all the fluid gets in there. The combi-plan has a splash guard to ensure that the fluid touches the film from the bottom.
You're pouring developer in, and the bottom gets filled first, so the film gets more development time from the bottom up. When you are pouring out the developer, the effect cancels out (the tank is inverted so the developer empties from the bottom first), sort of...
If you have to develop your film, say, 12min @ 68F, how do you time it... do you start the clock after all the developer is in? As soon as you start pouring in? When do you start pouring out? Etc.
Is this the reason why some people use there combi-plans and dunk the film through the tanks? (...but @ $65/per PLASTIC tank...)
Thanks for your help!
#1. "RE: LF Development Q: HP Combi-Plan" | In response to Reply # 0JBish130 Basic MemberSun 08-Jan-06 12:38 PM
In respect to the development times, you are correct. You fill from the bottom up and empty from the bottom up. Our small tanks work the same in this manner.
The Combi-plan comes with a small funnel. This will snap over the spouts for easy filling.
I've been putting the top on so that both spouts are on the same side. I've been filling the tank on it's side lately, filling from the bottom spout. This way, I get to crack open the top spout, which functions as a vent in this manner. This allows the fluid to enter much more quickly.
For timing, I use a small timer from Radio Shack. This timer will count time either up or down. I start the timing process as soon as I start filling the tank. The timing process finishes when the last of the fluid exits the tank.
When you empty out the developer, the film is still developing. The developing doesn't cease until the stop is introduced to the film. Thus, if it takes you 15 seconds to empty the tank, you can start pouring it out 30 seconds in advance (after 11.5 minutes in your example).
This way you can start pouring the stop in right at the 12 minute mark.
Relax. We try to be perfect on the timing process. It isn't uncommon for me to go over by as much as 15 seconds. This doesn't make a whole lot of difference even with slide film (which surprised me).
> "Is this the reason why some people use there combi-plans and dunk the film through the tanks? (...but @ $65/per PLASTIC tank...)"
This would secure the timing process down to the last second, but also leaves you working in the dark. I'd like to have more tanks, but at $65. each, that isn't going to happen.
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