DLG Temperature-Compensating Development Timer

[Mike in NY]

I just ordered the DLG Temperature-Compensating Development Timer. I formerly had a Zone VI compensating timer, but sold it when I moved into a home where I had a climate controlled darkroom. I moved again a few years ago and my current basement darkroom is subject to the vagaries of seasonal temperature fluctuations, so I ordered the DLG unit. If anyone has one and can share their experience or opinions, please do so. Thanks.

[peter schrager]

Please report back..would love to hear real world usage

[Mike in NY]

The timer arrived today, and my first impression from a hands-on visual inspection is very good. The packaging deserves mention, because it immediately reminded me of Apple's, with foam fitting compartments inside an attractive fold-down box with a finished surface. That doesn't have anything to do with the timer's performance, but it was nice not to receive a number of different parts in a single plastic bag dropped loose in a box with inflatable air bubble packing for a change! Instead, it was a nice touch of class. More importantly, as for the look and feel, the control unit feels sturdy, and the solid metal foot petal looks fine. The owner's manual discusses theory and principals of operation; temperature coefficients and compensation curves; operating instructions, and other information. So far so good. The proof of the pudding will come in its use; I'll report back.

[Mike in NY]

I tested the DLG temperature compensating timer today, and it performed extremely well. As noted in the user’s manual, the timer compensates for a temperature co-efficient of 2.5, which is equivalent to using Ilford’s time-temperature chart that can be read on page 4 here: https://www.ilfordphoto.com/amfile/f...9/product/708/
Alternatively, the unit can be ordered with a different co-efficient of your choice.

I ran four tests as follows:

Test #1
I placed both my Weston thermometer and the timer’s stainless steel probe into 1 liter of stirred water. My thermometer read 64.5 degrees F, which matched the 18 degrees C reading from the timer’s probe (the timer shows whole C degrees with no decimal places). I checked the Ilford chart and determined that a 2:00 minute development time at a “normal” temperature of 20 (C) should take about 2:30 at 18 (C). So I activated my stopwatch and the timer at the same time. When the timer read 2:00, the stopwatch read 2:29 – right where I expected it to be.

Test #2
I let both the stopwatch and the timer continue to run from the first test. I knew from the Ilford chart that when the timer got to 5:00, the stopwatch should read close to 6:00. Sure enough, it read 5:58. The temperature did not significantly change during this time.

Test #3
I prepared another liter of warmer water. My Weston thermometer read just over 75 (F), which matched the timer’s temp of 24 (C). I activated both the stopwatch and the timer at the same time. I knew from the Ilford chart that when the timer reached 3:00 the stopwatch should read just over 2:00. Sure enough, it read 2:05.

Test #4
I let both the stopwatch and the timer continue to run from Test #3. I knew from the Ilford chart that when the timer got to 10:00, the stopwatch should read just under 7:00. It read 7:03, but then I checked the temperature and saw that it had cooled about a third of a degree F, which explains the additional time that the timer “knew” was needed.

I’m really glad I have a new compensating timer to replace the Zone VI model I sold years ago when I had a climate controlled dark room in my former home, unlike the chilly darkroom I have now. This will make development so much easier.