I use LPD but have a box of Formulary 130 in the freezer and wonder this: Does the pour-back accelerate the oxidation because of the aeration? I use a funnel with a 6" plastic tube to try and keep it from churning in the bottom of the jug but I often wonder if I'm worrying about nothing. (I printed some 5x7s and cleaned up already, so I get to be on the internet with the first of maybe too many glasses of wine.)
s-a
You think pouring back to the bottle oxidizes the dev more than letting it sit in a tray? Oh no, my friend.
LPD in a capped bottle lasts a very long time. Even working solution does. At times when I print little, my replenished working solution, and 2:1 diluted replenisher, last for a good bit more than six months. I have not been able to exhaust it yet, other than the time I left it in the tray for days because I forgot it. That should tell you something.
Even so, the exhausted working solution was brought back to life quickly with a heavy dose of replenishing solution.
Then I'll quit worrying and try the 130. The current LPD is almost shot.
thanks,
s-a
Just to provide some interesting control/reference data, Richard Henry tested the open tray life of an unused 1:1 Dektol working solution at 1-day intervals out to 6 days at 68-70F using Ilford Ilfobrom.
Through two days, statistically identical results could be produced as long as development time was extended. After 2 days, a continuous decline in maximum reflection density was observed, which could not be compensated for by extending development time. However for reflection densities of ~2.00 and below, identical results could be produced even out to 6 days by extending development time. The required increase in development time followed a logarithmic progression.
Thanks. I was having trouble reconciling Shawn's post with my own experience. I've continued work on a print the next day and everything was consistent from where I left off ( for example, make the "working print" one night, then work on a "final" the next night. ) The different experience may be explained by some procedural difference. For example, I routinely develop for 2 minutes and up to 2m15s. There are other possibilities as well. I wonder if visible yellowing of dektol was correlated to decrease in max density.
The difference may be developing time. The way I read Shawn's post development time was kept constant at day 0 and day 1. Henry was able to duplicate day 0 and day 1 prints by increasing development time by about 25% (his normal time at a 1:1 dilution was 1:30). Shawn is using the more standard dilution of 1:2 so presumably the required % increase in development time would be greater - although this could potentially be offset by Shawn having bottled it while Henry kept it in an open tray for the entire duration of the 6-day test. Another variable is the paper itself. Henry ran his tests with graded Ilford Ilfobrom (this was in the mid-1980s). Different papers might respond differently.
Note also Henry was measuring reflection densities objectively. In reality a measured fall-off in d-max from say 2.40 to 2.30 might not be detectable by eye, since the eye is more sensitive to small changes in light tones than very dark tones. But here again, there are variables to consider such as viewing conditions, the subject matter and tonality of the picture being printed, etc.
The most important point I take from Henry's Dektol tray life test is that after day 0, processing had to change in order to compensate for the change in developer activity. Since I don't like to mess with print development times (I use Dektol) I know I can't keep the working solution past a single printing session even if it is relatively fresh. Not that I ever did that anyway. I want the most consistency I can get from my materials.
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