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#1
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Stopclock Pro question
I bought a Stopclock pro enlarging meter a couple of weeks ago and just got around to hooking it up tonight and using it for the first time.
After making a test strip as per the instructions, then setting the timer to the chosen exposure (based on the test strip to make the first print) I discovered that the two don't match up. e.g: Base exposure of 4 sec followed by 8 exposures at 1/4 stop increases. Test strip looks good progressing across the sheet in 1/4 stop increments. Test Strip = Base 4 sec followed by /1/2/3/4/5/6/7/8 incements of exposure with step 4 being optimum. So Base of 4 sec followed by 4 presses of the up bottom. Exposure made at this setting. The test strip exposure and the exposure of the print don't equal each other. This is very apparent when comparing the shadow detail of both the test strip and the print. The shadows at increment 4 on the test strip are detailed and the shadows on the print are almost black. The test strip indicated increment 4 which means 4 presses of the up button, but to get a match between the test increment 4 and the print it turned out to be 2 presses of the up button? Obviously I expected the print to match the chosen test increment exactly but in this example its a 1/2 stop out. Any thoughts? I dont think Ive managed to explain this very clearly but I hope you can get the drift. |
#2
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You made a base exposure, and then covered the first strip, or made the first exposure on top of the base exposure?
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#3
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Base exposure then covered the first strip. Maybe I should go back into the darkroom this morning and try again.
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#4
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It sounds as though your enlarger lamp has a lengthy warm-up time, so that the incremental exposures are shorter than they should be. What enlarger are you using, and does it have a stabilised transformer?
When interpreting the test strip, remember the first exposure is the base so if the fourth strip is the right one then it's THREE presses of the Up button (i.e. base plus three increments). |
#5
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Hi Richard its a Devere 504 with tran-stab. I didn't count the base exposure strip as an increment when assessing the optimum strip.
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#6
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Kev -
I've not come across this problem with that enlarger before; I think the Transtab normally switches the lamp on immediately. However you could try switching the delay feature on (see User Options, p14 of the manual). If you still can't get a match, I suggest using the full test print option rather than incremental. This produces a sequence of full exposures rather than a series of small increments, and will guarantee a match. |
#7
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What gems are hidden within this beast? How do I set that up, should I want it?
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#8
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Press and hold down the focus/options button until the display reads User then press the button 4 times and the display should show test then toggle the up and down exposure time buttons to select either Sep for seperate or inc for incremental test exposures, there are several user options, all accessed through the focus/options button.
Hope this helps. |
#9
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Thanks Richard I'll get going with your suggestions. Last night I was thinking that the 'intermittency effect' was at the root of the difference between the test strip and the work print? If that was the case the ''full test print option'' would be the answer.
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#10
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Quote:
The intermittency effect is quite common, particularly with voltage stabilisers. The smaller Durst and Kaiser stabilisers are common culprits, both take half a second or so to switch the lamp on after power is applied so with incremental exposures of just a few seconds or so this can significantly affect the total exposure. For example, a total exposure of 10 sec made up of five increments would be 2 sec shorter than a single 10 sec exposure (which itself would be 9.5 sec). |
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