Enlarger Questions

Ben johns

Ben johns

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Ben
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Is there a chart or formula that I can use to adjust times depending on how high the head is? So say I made a print on a 6x4 piece of paper and wanted to make an identical one on a 12x8 piece of paper, is there a way of using the height gauge on the enlarger to adjust the times?
 
2 stops open or 4 times the time, roughly, for that increase. I'm sure I did have a chart once but is based on inverse square rule but slightly complicated by the need to allow for the change in lens to negative distance needed to focus as well as the head height change. Just working on the increase or decrease of area for the same image on the paper is simpler.
 
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Ben johns said:
a print on a 6x4 piece of paper and wanted to make an identical one on a 12x8 piece of paper,
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dmb said:
2 stops open or 4 times the time, roughly, for that increase.
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)
Thanks for the pdf charts but tbh I find your approxiamative adjustments for Bens print sizes to be much easier to remember .(y)

Saying that, a 10x8 to 12x16 has me more confused..........Would that be one stop open / twice the time duration ?? ( I need to sleep before tryig to figure it out using charts :LOL:)
 
Asha said:
.Would that be one stop open / twice the time duration ??
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About! (Close enough for government work, anyway.) Basically, double the area, double the light/time needed. If you want/need the print to be perfectly exposed, you could calculate the exact time extension needed over the doubling but whether you (or, possibly more importantly, anyone else) would notice the difference...
 
Nod said:
About! (Close enough for government work, anyway.) Basically, double the area, double the light/time needed. If you want/need the print to be perfectly exposed, you could calculate the exact time extension needed over the doubling but whether you (or, possibly more importantly, anyone else) would notice the difference...
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Cheers Nod
That will prove rather helpful ;)
 
Or use an enlarger light meter. Spot meters used to exist (I have one) but an averaging meter would still measure the light attenuation.
 
StephenM said:
Or use an enlarger light meter. Spot meters used to exist (I have one) but an averaging meter would still measure the light attenuation.
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Thinking about it, I actually have an attachment for the Lunasix ...... ;)
 
second question. I have a set of ilford contrast filters. They go from 1-7. The set came with a wheel to calculate exposures. Untitled by benjohns4 johns, on Flickr
As you can see some of the filters have the same adjusted time. Does that mean that 1 + 5 have the same time even though 5 is darker than 1 ?? :s
 
According to this thread on Photorio, it looks like these are Multigrade 11 filters with the calculator. Worth a read (apart from trendland!), rather than me repeating the views here.
 
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Peter B said:
According to this thread on Photorio, it looks like these are Multigrade 11 filters with the calculator. Worth a read (apart from trendland!), rather than me repeating the views here.
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Sounds like it would make sense to buy a brand new set, bit annoying. The ones I have got perfectly into the filter tray, I have a meopta opemus student, is there a chance I’ll have to cut new ones down to fit? Or would I be able to just hand hold a filter underneath the lens? Be easier than just pulling out the tray each time
 
Ben johns said:
Sounds like it would make sense to buy a brand new set, bit annoying. The ones I have got perfectly into the filter tray, I have a meopta opemus student, is there a chance I’ll have to cut new ones down to fit? Or would I be able to just hand hold a filter underneath the lens? Be easier than just pulling out the tray each time
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The info I have is that the filter drawer takes a filter 48mm square, but simplest way to check is to take it out and measure it. The drawer filters are apparently gelatine, whereas the below filters are stronger resin, so holdng gels below the lens doesn't seem like the best idea, plus it would mean you wouldn't have free hands for dodging or burning.
 
I’ll have a look. Shame to have to buy knew ones but I suppose there’s no way of knowing if they’re working as intended
 
Peter B said:
The info I have is that the filter drawer takes a filter 48mm square, but simplest way to check is to take it out and measure it. The drawer filters are apparently gelatine, whereas the below filters are stronger resin, so holdng gels below the lens doesn't seem like the best idea, plus it would mean you wouldn't have free hands for dodging or burning.
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yea I think I’d have to cut them to size if I bought a new filter set.
 
I just did some testing and made a print, I think the filters and the calculator work fine. Though I did use the darkest filter and had to add 10% more to get it as I like and the contrast still asnt overly high so maybe they are at the end of theyre life
 
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