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Irishvoyageur
17-Feb-2017, 20:17
I have this old resurrected enlarger which I believe is similar to the Durst 138. I just started using this enlarger with PH212 light source. This is a smaller bulb than the original and only 150 watts. When I enlarged to make an 8x10 print, I had to stop down to F32 to get a printing time of about 25-30 seconds. I am not using any filters and am using the standard condensing lenses (latico 200 and 240). I am wondering if I am compromising the quality (sharpness) of my enlargement by using such a small aperature? This is my first time at printing so I need all the help I can get. Thank you!

Luis-F-S
17-Feb-2017, 21:14
Try to get a dimmer or a transformer to decrease the voltage, thus lower the light intensity of the bulb. This will allow you to print at a larger aperture. You can also try a G40 bulb, it's 150 watts and a much larger envelope (bulb size) which should give better coverage. L

loonatic45414
17-Feb-2017, 22:03
I built a dimmer knob & switch box. Switch in one position is full bright for focusing, then switch to variable for printing.

I try to stay on f/8 around 20 seconds which allows burning & dodging without cooking the negative. Makes the bulb last much longer too.

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koraks
18-Feb-2017, 02:49
I ran into the same issue with a Durst 138 with a 250W bulb. I just screwed in a 75W or a 150W bulb and went my merry way.

Irishvoyageur
18-Feb-2017, 06:10
Thanks all! I will look into obtaining or making a dimmer. Would using some type of neutral filter work as well in the filter holder near the lamp source?

loonatic45414
18-Feb-2017, 08:05
If you used a gel filter it would likely discolor or melt over time. My bulb is expensive & hard to find, so the dimmer was feasible. If you have a standard screw bulb, just find a lower wattage one.

I would recommend one made for enlarging, since they're carefully coated for the right color temperature, also a lot of household ones have a clear spot at the base and aren't fully coated. Maybe someone else could comment on the feasibility of using a standard light bulb, whether 3200K or daylight balanced. I saw a cold light head with a fluorescent source once, but those remain glowing a bit after being turned off. I'm not sure I'd like that.

If I lived in a remote place, I don't think it would be a major issue although having access to a special enlarger bulb, I'd prefer that.

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cowanw
18-Feb-2017, 08:43
My enlarger has a sheet of frosted milky plastic that undoubtedly decreases light transmission.

LabRat
18-Feb-2017, 09:37
Using a dimmer on the lamp changes the color temp and shifts the spectrum towards red, so an increased cut in blue/green, but can throw MG or color balance off...

As suggested, putting something in the light path, or a lower wattage lamp would be better...

Steve K

Luis-F-S
18-Feb-2017, 10:16
You can also use a longer lens to raise the head a bit and cut down on the light. If your print looks good I wouldn't worry about it.

loonatic45414
18-Feb-2017, 10:49
Using a dimmer on the lamp changes the color temp and shifts the spectrum towards red, so an increased cut in blue/green, but can throw MG or color balance off...

As suggested, putting something in the light path, or a lower wattage lamp would be better...

Steve K
I hadn't thought about color.

I do black & white only for the moment. Even so, I will have to factor any contrast into my standardizing.

It would be interesting to see if there's any shift with dimmable LED's.

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Jason Greenberg Motamedi
18-Feb-2017, 11:43
To solve this problem with the 183S I put a ND filter into the filter drawer. If you are worried about heat you can also use the heat absorbing glass filter (or add some opal glass to it) that slides in between the filter tray and the bulb.

ic-racer
18-Feb-2017, 13:02
I am wondering if I am compromising the quality (sharpness) of my enlargement by using such a small aperature?

Make a print at F16 and F32 compare the prints side by side. That is the way everyone does it.

loonatic45414
18-Feb-2017, 13:35
I mount my lens board onto a bellows with a mirrorless digital camera & view enlarged digital images looking for distortion, corner focus, light drop-off, etc. I stick with f/8 or f/11. F/16 is usable but I don't use 32, 22, 5.6, or wide open (except to focus)

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MartinP
21-Feb-2017, 04:57
By far the simplest solution is to buy yourself a few 75W bulbs, to replace the 150W when needed. Note that there is also a 250W bulb in the pseudo-Photocrescenta series, which is still occasionally available. That covers the rare possibility that the enlarger can cope with the heat and that you want to make huge enlargements!

Luis-F-S
21-Feb-2017, 07:49
Don't forget to add a blower for bulbs over 200 W I use one regardless of wattage. Also the G series bulbs have large envelopes and you can get them in different wattages.

Duolab123
3-Mar-2017, 17:45
There's thousands of these floating around for a 212 bulb
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