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> If in doubt, change the developer!! |
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#1
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If in doubt, change the developer!!
My last two 'quickie' sessions in the darkroom are best forgotten, having gone into both with total 'brain fog'.
On both occasions, I started with a test-strip, which was fine, but then the print made directly afterwards was about 1 to 2 f-stops over exposed. Another one would be made and it would be fine, then the next would be dark again. Trying to work it out, I tried a different paper, which did the same. I gave up quickly on the first session, putting it down to tiredness. The next session on the following day followed the above. I was totally confused. The third session, with a clearer head, I read what was in big writing in my note pad (as I keep notes for each session, JUST in case I want to repeat something that or the next session). In capitals it said, 'TRY CHANGING THE DEVELOPER!' Not knowing what prompted this text, I drained and rinsed out the slot in my Nova and put in new developer, even though the throughput written on my whiteboard was nowhere near Ilford's recommendations per litre and the developer colour was good. But, from the off, everything worked fine now and I was able to do a few more good prints. I'm returning today for another session. Well, I'm glad that it's all sorted, but why was the developer doing something okay one minute and then not the next? A previous problem, with staining around the margins was down to the developer as well, even though the stains only occurred when the prints were put into the fixer! Oh, and something else. I couldn't work out why my negative was so dark on the baseboard. The negative may have been a tad dense but even with a fully opened aperture, I couldn't see the grain through my grain focuser. A couple of minutes later... I had left the lens cap on the enlarger lens!!! I've done this a few times on my rangefinders, but not on the enlarger - that's a new one for me. Dooooh!!!! just about sums it up. Terry S |
#2
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Dear Terry,
Sorry to hear about your misfortunes. To clear up brain fog and tiredness, many photographers use a chemical substance known as caffeine. I can recommend it. Installing an espresso machine in your darkroom would give you instant access any time an emergency dose is required.
__________________
Regards, Svend |
#3
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Well, just when I thought that I'd sussed the problem, it carried on happening after a new solution of Ilford MG developer was put into the Nova slot processor. I had to make 12 prints for a postcard exchange, when I only needed 7. On the good side, they were all small postcard sized bits of paper and not 10" x 8" 's!
Through experience, I'm thinking that the developer has gone off, despite being clear and in full bottles with oxygen replacement in each bottle. I think it's the last of a 5 litre purchase and not too old. I'm going to mix up some D72 this afternoon, just to check that it is the developer, for if not, I'm not sure what I'll do next...? Does anyone know why a developer would produce a good print, followed by a very dark print, followed by a good print etc.? Terry S |
#4
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Are you sure it is the developer? What enlarger do you use? I had a similar problem some time ago with a 240V enlarger bulb. It turned out to be variable voltage although this was within 'specification'. Solved by running the enlarger off a 12V battery and invertor.
Mike |
#5
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Terry everything you have said and done suggests that something other than the developer is at fault. Mike's idea or something else that affects exposure would in a variable and unpredictable way does fit with the symptoms you have described
Mike |
#6
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Just when I thought the d72 solved the problem, it started happening again after the second print. Prints 3 and 4 were again darker by about half stop, so we can conclude it's not the developer, as it has always been in the past.
My enlarger is a basic 2 1/4 square omega model, that runs off 240 mains voltage, and currently uses a standard 100-watt bulb. So thinking about it, it must be either the bulb or the RH designs print analyser. Luckily I have spares of both, along with a low voltage bulb, that people started recommending a while ago on the forum. So my next session, will be replacing and trying each and hopefully nailing the problem. Thanks for all suggestions so far. Terry S |
#7
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Voltage spike or voltage regulator required???
Well, I've had another 2 hour session in the darkroom today and I am none the wiser about what is causing a couple of good prints / test strips, following by much dark ones and then back again.
Changing the developer didn't work, so today I tried out my spare (more basic and without the measuring unit) RH designs f-stop timer and then a different 240 volt bulb. The result? I still got the same occasional good prints followed by dark prints, followed by a couple of good ones again. From this I think I can presume that these three things are not the cause. Now I know just about zilch about electronics, but have heard or read in the past, the words, 'voltage spike' and 'voltage regulator'. My first stop was ebay, which gave lots of options but I'm totally in the dark if any of these would help? I believe that I have an extension cable that I used to use with my laptop and studio lights when out and about and working with petrol electric generators. I'll take a look at it when next in the darkroom in a few days time, but if that doesn't sort it what would be worth trying next? ANY suggestions would be most welcomed as I can't ignore it, as it's really beginning to eat into my darkroom paper, with various test strips and prints, but it is also slowly driving me crazy as to what is causing this all of a sudden. Many thanks in advance for any help given. Terry S P.S. I've just thought that I will put the question out to Photrio users as well. I much prefer the advice given on this site, as so much nonsense is given on the 'other' site, but one never knows, there may be someone who does actually know what they are talking about and maybe able to help... fingers crossed. Last edited by Terry S; 3rd January 2022 at 05:19 PM. |
#8
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I have had a similar problem when printing. When fine tuning the exposure for the print I altered the time one way but the resulting print responded the opposite to what I had expected. After discussing the issue with Richard Ross at the time we thought it may be due to mains voltage variations. I bought a voltage stabilised transformer and whilst not being certain this was the cause of the problem it was a few years ago and I have not experienced the problem since. I think there are reasonably priced voltage stablised 12 volt transformers used for low voltage lighting. Ones made by enlarger manufactures are quite expensive.
Tony |
#9
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So you've tried fresh developer, swapped out the bulb and the timer, but no change.
The latter two would be the most obvious suspects you'd say. I am not familiar with the British grid stability, over here in Holland it's usually pretty solid. And if it had always worked before, it would be strange that the stability changed this much all of a sudden. Unless they just recently built a big factory next door or something... I wouldn't invest in a stabilizer just yet, try to pinpoint the problem first. I'd start by inspecting your enlarger closely. Are all connections and the bulb fitting solidly mounted and clean? Perhaps it has an extra switch in the power lead (like my Meopta has) or on the front/back, try operating that a couple dozen times to "clean" the contacts a little. Is there a fuse somewhere inside? Long shot, but you could try and replace that as well. I remember British plugs having a fuse inside, but I could be wrong here. Do you observe a change in light intensity when leaving the enlarger on for a longer amount of time, eg 30 seconds or one minute? Also try wiggling the cables to see if that does anything (obviously it shouldn't). And what about your lens aperture, does that still operate as expected? If possible try another lens, just to rule it out. Do you see any light intensity variations in any of your other incandescent light bulbs (not LED or energy saving, those have built-in regulators) in or around the house, assuming that possibly you still have some of those installed somewhere? I'm not sure of you technical skills and/or confidence, but it would tell a lot if you'd measure the grid voltage during an exposure and see if it changes during the exposure. You'd need to compare a good exposure's measurement with a bad one. Or just measure if the voltage changes at all over time, eg 15 or 30 minutes,regardless of using the enlarger or not. Also try another wall outlet for your enlarger if possible. Perhaps it's a bad / loose connection inside the wall outlet. Very rare, but I've seen them. |
#10
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Quote:
To be fair on this occasion however there did seem to be some good suggestions. I'd have no knowledge of the grid and substation set up in your area Terry but all I can say is that my area I have never experienced spikes but have had issues with bulb lighting fluctuations due to a mixture of arcing where the halogen bulb's spikes fit into the ceramic holder and bulbs on their way out Gut instinct still suggests that it is an exposure problem caused by the bulb or its connection inside the enlarger Mike |
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