Why am I not surprised!?!?

[walbergb]

A couple of days ago, I made a couple of copies of a print, split toned one of them it in sepia toner, and laid both out to dry on the drying rack. Today, I was back in the darkroom with two goals: (1) to finish the prints by toning them in selenium, and (b) make a couple more copies of the toned print since I liked it so much. Same variables, but today the prints came out 1/3 stop lighter than a couple of days ago! This always seems to be the case. When will I learn!

 

[John Bragg]

Did you make fresh developer for each session ? There shouldnt be that much diffference unless something has changed with time, temperature or developer strength

 

[walbergb]

All chemistry was fresh for the first session. Only a few prints went through. I use the factorial development method and the times were the same (+/- a second or two) for both sessions which tells me the developer is just as active today as it was in the first session. I suspect something mechanical such as the enlarger bulb or the timer. Question is what will my exposure time be tomorrow:confused:

 

[swittmann]

Bob, did you compare dry print vs dry print? (Well, you certainly did... it was just an idea)

Another idea would be to warm up the bulb before you start printing.

 

[~andi]

Could also be power fluctuations with the mains. We have rather loose tolerances here +/−10 %. Which allows for a range of 207-253 V. Did you print at the same hours in both instances? If you're printing on variable contrast paper, is the contrast the same between the two sessions? Just a shot in the dark.

 

[walbergb]

Bob, did you compare dry print vs dry print? (Well, you certainly did... it was just an idea)

Another idea would be to warm up the bulb before you start printing.

Yes, I did compare dry-to-dry prints. And, I do warm up the bulb before printing. You gave me an idea: I should use my light meter to measure the light over a few printing sessions to see if there is any significant fluctuations. That would at least tell me whether the problem is with the enlarger side of the process.

 

[walbergb]

Because I use a community darkroom, I tend to print at the same time of day. However, the darkroom is contained in a larger facility and part of a downtown grid. I thought my enlargers (Beseler 23CII retrofitted with a Dichro S lamp house, and a Beseler 45S) had built-in voltage regulators that took care of voltage fluctuations. The enlarger in question is the 23C, which I tend to use for 35mm.

The paper was from the same batch, and I dialed in the same amount of filtration on both occasions. I'm focusing on the enlarger system until I rule it out. This isn't the first time I've experienced this unexpected result. Maybe it's time to change the bulb.

 

[MattKing]

Check the aperture on your enlarger lens - is it giving repeatable results when you adjust settings.