View Full Version : Print developer replenishment?

Fred Braakman
3-Nov-2007, 12:09
Hi all,
I often find that development times of prints are not always reproducable. I do my test prints, get the exposure, and develop as usual. Then when I repeat the rpinting at a later date, and I make fresh developer, the printing is over exposed.

I follow Kodak's recommendations as to the # of prints that a batch of developer should be good for. In fact, I never go to the max. (I use Dektol.)

Is there a way to "replenish" developer as it is used up? Do you recommend a max # of prints to develop in a developer? I usually print 11 x 14, about 20 prints per batch of working solution.



Peter Lewin
3-Nov-2007, 14:15
If you are always developing fewer square inches than Kodak recommends as a max, my quess is that you might be experiencing temperature drift rather than developer exhaustion. At least in my basement, the tray temp usually drops over the course of a printing session, so on another day, the first prints are being processed at a higher temp than the last prints of the previous session. I get around this using a ZoneVI compensating timer, but the "classic" solution is to ratio the "first appearance" on the print to the total time. In other words, let's say that you drop a print in the tray, the image begins to appear in 30sec and the print is ready at 2 minutes. Your total print time is 4 times the appearance time (4 x 30sec = 2min). So if your tray temp cools, and the appearance time becomes 45sec, you multiply by 4 and your prints should be done at 4 x 45sec = 3 min. If you are already adjusting for temperature, and my guess of the cause of your problem is way off base, please ignore!

Michael Gudzinowicz
8-Nov-2007, 08:23
For consistency during one session, I'd suggest using as large of a developer volume as possible to avoid rapid exhaustion. Also, if you are using Dektol, dilute it 1+1 rather than 1+2. The capacity will be a bit more than the 1+2 for the same volume of undiluted stock, but it will develop deep tones more consistently with use.

I'm not sure what your development times are, but adjust exposure so RC prints are developed for at least 1 min, and fiber base, 2 minutes minimum. Papers are developed almost to completion. If development times are short and control tonality rather than exposure alone (nearly so), you will have problems with consistency.

A good part of the loss of developer activity is not due to oxidation if the 1+1 dilution is used. It is due to the absorption of carbon dioxide by the very basic solution, which forms carbonic acid lowering the pH and activity. One old school method for renewing activity is to add 1 oz of a 10% (w/v) sodium carbonate (washing soda is fine) solution to the developer. The amount isn't critical - use enough to get get the development time of a test strip back in line.

If the marked variation occurs between batches as described, it would seem that you aren't monitoring activity by noting the emergence time for mid-tones as mentioned in the preceding post. If you don't do that, consider exposing a test negative or step tablet at the same magnification and exposure before each session, and note the emergence time and result. Add carbonate if required, or change development times.

The carbonate should have little effect on image color or fogging with modern papers. In the past, bromide might be required along with carbonate to boost activity.

Fred Braakman
8-Nov-2007, 11:38
Thanks peter and Micheal,
I do observe the emergence time of the image as I start the development, and it does tend to drift, from about 25 seconds to about 35 seconds. This may be a factor to take into account. I do have temperature fluctualtions in my dark room.

I will use your suggestion to adjust the total development time Peter, and also Michael's, to add a bit of carbonate to the developer. As well, a step tablet as a test strip is a good idea.