Don Dudenbostel
22-Jan-2016, 15:08
We all make foolish mistakes and a couple of years ago thinking I was retiring and moving across the US and might not have a darkroom I sold my Durst 138 and 3 spare bulbs. Life is uncertain and always subject to change and I didn't move and didn't retire. I recently set out to find another 5x7 enlarger and I found a really nice one in almost the same condition as my original just 3 hours away. The sad part is it had a 211 bulb in it so I had to find a suitable substitute. I tried a 300 W sylvania bulb that some recommended, a G40 150 W bulb, LED flood lamp with opal glass diffuser and various combinations of diffusion material and bulbs. If you're only printing up to 4x5 then the 300 W Sylvania is a good alternative but I print 5x7 negatives and even coverage of illumination was terrible.
Next I tried the 150w G40 and had pretty good luck with it and feel it's a possible alternative for 5x7 negs. I was able to adjust illumination to be pretty even across the entire neg. I had to reposition the socket in the enlarger to the horizontal position due to the design of the filament but this might vary with brands of bulbs.
In the sale of my original 138 I had a Componon S 180 that went with it. Not having a 180mm laying around and not wanting to spend a bunch of money I picked up a mint 210 G Claron. I used a 240mm G clarion years ago on my 8x10 enlarger and it performed quite well so I figured give it a try with a 210mm. Well it works great but it's slow. F9 wide open is an issue with a dim light source. I rarely print larger than 11x14 and with the G40 my exposures were around 1 minute with a typical negative using multigrade Ilford FB and a filter. That's OK but you can grow old burning in a neg. Ideally I like to print two stops down around 30 seconds.
My next try was the G40 150w again but this time I connected a Variac to it. The bulbs are around $4 so boosting the voltage cutting life of the bulb for additional output was no big deal. I figured if it worked I'd pick up a couple of cases of bulbs and be set for life (I'm old). By boosting the voltage to 140v I picked up 1/2 stop or just a touch more. This is getting closer but I wanted to see if I could get even more light.
I read several articles on the internet about LED sources so I ordered a 60w equivalent 3000K LED flood light and a piece of opal glass from Edmund Scientific. I placed the bulb in the horizontal position and the opal glass in the filter tray. Unfortunately the flood that I had wasn't very even in illumination but I think there are some that might be better. Also the opal glass cut my light back to about what I had with the G40. I did some research and there are bulbs that have 120w equivalent output which is double what I tied indication this might be a workable alternative.
My next attempt was with a light panel I bought off ebay. Search this --- 21W Dimmable CREE LED Recessed Ceiling Panel Down Lights Lamp. The one I bought was a 21w non dimmable 3000K panel with driver. It arrived this week poorly packed and seriously warped but was ok to experiment with. What I would up having to do was remove the outer part of the frame. With the excess metal it was too big to fit in the compartment where the bulb goes. The aluminum was so soft I was able to break it away leaving a bit of a rough edge. What I would u doing was place the panel inside the bulb compartment facing the opening where the filter holder is. I ran the bracket to adjust bulb position up until it wedged the light panel between it and the top of the lamp housing. I had wired the panel with a household plug and screwed an medium base to household adapter into the lamp socket. closing the lamp housing up and flipping the enlarger on revealed the light was extremely even and pretty bright. I put the meter to it and found .2 stops variation from center to corner and each corner exactly the same. This is about what I'd expect from normal falloff of the lens.
The next step was to see how it printed. I had a few sheets of Ilford MG FB and a few normal negs handy and and gave it a try. To my delight I found a full frame print on 11x14 paper printed with a 2 to 2-1/2 filter at f16 or 16-22 and 28 seconds. A few more dense negs printed slightly longer but this is in the range of what I consider ideal. Initially I think contrast is about what I was getting with a tungsten bulb and times are where I want them. I have no heat and the light will last for decades hopefully.
Hope this helps. I'll post as I get more into this but think this might be a reasonable solution for home of us that print smaller.
145427
Next I tried the 150w G40 and had pretty good luck with it and feel it's a possible alternative for 5x7 negs. I was able to adjust illumination to be pretty even across the entire neg. I had to reposition the socket in the enlarger to the horizontal position due to the design of the filament but this might vary with brands of bulbs.
In the sale of my original 138 I had a Componon S 180 that went with it. Not having a 180mm laying around and not wanting to spend a bunch of money I picked up a mint 210 G Claron. I used a 240mm G clarion years ago on my 8x10 enlarger and it performed quite well so I figured give it a try with a 210mm. Well it works great but it's slow. F9 wide open is an issue with a dim light source. I rarely print larger than 11x14 and with the G40 my exposures were around 1 minute with a typical negative using multigrade Ilford FB and a filter. That's OK but you can grow old burning in a neg. Ideally I like to print two stops down around 30 seconds.
My next try was the G40 150w again but this time I connected a Variac to it. The bulbs are around $4 so boosting the voltage cutting life of the bulb for additional output was no big deal. I figured if it worked I'd pick up a couple of cases of bulbs and be set for life (I'm old). By boosting the voltage to 140v I picked up 1/2 stop or just a touch more. This is getting closer but I wanted to see if I could get even more light.
I read several articles on the internet about LED sources so I ordered a 60w equivalent 3000K LED flood light and a piece of opal glass from Edmund Scientific. I placed the bulb in the horizontal position and the opal glass in the filter tray. Unfortunately the flood that I had wasn't very even in illumination but I think there are some that might be better. Also the opal glass cut my light back to about what I had with the G40. I did some research and there are bulbs that have 120w equivalent output which is double what I tied indication this might be a workable alternative.
My next attempt was with a light panel I bought off ebay. Search this --- 21W Dimmable CREE LED Recessed Ceiling Panel Down Lights Lamp. The one I bought was a 21w non dimmable 3000K panel with driver. It arrived this week poorly packed and seriously warped but was ok to experiment with. What I would up having to do was remove the outer part of the frame. With the excess metal it was too big to fit in the compartment where the bulb goes. The aluminum was so soft I was able to break it away leaving a bit of a rough edge. What I would u doing was place the panel inside the bulb compartment facing the opening where the filter holder is. I ran the bracket to adjust bulb position up until it wedged the light panel between it and the top of the lamp housing. I had wired the panel with a household plug and screwed an medium base to household adapter into the lamp socket. closing the lamp housing up and flipping the enlarger on revealed the light was extremely even and pretty bright. I put the meter to it and found .2 stops variation from center to corner and each corner exactly the same. This is about what I'd expect from normal falloff of the lens.
The next step was to see how it printed. I had a few sheets of Ilford MG FB and a few normal negs handy and and gave it a try. To my delight I found a full frame print on 11x14 paper printed with a 2 to 2-1/2 filter at f16 or 16-22 and 28 seconds. A few more dense negs printed slightly longer but this is in the range of what I consider ideal. Initially I think contrast is about what I was getting with a tungsten bulb and times are where I want them. I have no heat and the light will last for decades hopefully.
Hope this helps. I'll post as I get more into this but think this might be a reasonable solution for home of us that print smaller.
145427