Light source for Beseler 45M with 6x7/35mm

[Eric Woodbury]

I have two enlargers in my DR. Both Beseler 45Ms. One is outfitted for LF work, 8x10, 57, 45. It has a V54 Aristo coldlight and it prints very fast. There is plenty of light. I have a second 45M that uses the standard tungsten bulb and condenser. I use it for 6x7 and 35mm, but I don't find it to be fast enough. I wish it were 1 or 2 stops faster.

I was in Home Depot last night looking at light bulbs and noticed that they now carry a small selection of LED lamps. I'm wondering if I can use such a lamp, a 60W equivalent LED spot light and a diffusor to make a diffused light source that is fast. Actually, this can be done, but has anybody done this or similar, and what were your results? I'm curious how fast, i.e. a typical exposure for an 8x10 on VC paper? How much contrast can you extract from the light? Is there enough blue light to get to the high contrast end of the VC paper's capability?

I've been designing with very high brightness LEDs and laser diodes for a work project. Some of these are 450 nm blue LEDs, but I fear that even these don't have enough 'blue' to make the most of VC contrast. I know that violet LEDs would probably work better, but I'm not anxious to start another project that takes me out of the DR.

So, what are you all using? How fast is it? Do you get full contrast response? Have you tried LEDs, CFLs, some special form of cold-cathode light, tungsten, 12V halogen-tungsten, etc?

Thanks so much. Eric

[Robert Ley]

Eric,

Have you tried a higher wattage bulb. I have a 150watt PH112 bulb and I believe they may even make a 250watt bulb. What size bulb do you use? When I used my 45 with the 150 watt bulb there was almost too much light to use the best f stops.

Cheers,
Robert

[Eric Woodbury]

I don't know what I'm using. I know it is not 250W. That would seem like too much heat for that housing. The bulb is whatever one can buy at Freestyle Sales.

Thanks, I'll check into that further.

Edit: it's a #212. 115 to 125V. All it says.

[Robert Ley]

Eric,

The 212 is 150watt and you could try a 213 which is 250watt. I don't think that it would be too much for your condenser head. You can get the 213 here:http://www.bulbdirect.com/products/catalog.php?cat_id=412&page=10

[domaz]

DIY Lead Heads have been discussed quite alot on APUG- it is possible but a lot of work and requires a lot of heatsinking. Cheap LED bulbs aren't going to do it- your going to need a bunch of 3W LEDs which get HOT. They also need a lot of current regulation, switching current regulators aren't cheap and don't even think about using resistor if you want the LEDs to last.

[dsphotog]

150w should be plenty bright, if not the 250 watt is ok to use since you'll have shorter exposures.
Is the condenser adjustment set for the smaller format?

[ic-racer]

Has your bulb darkened? Maybe its time for a new bulb.
Tungsten bulbs are cheap. It will take many decades for a high-power LED system to pay for itself in tungsten bulb savings. But if your problem is not enough light, LED would be the last thing I would think of.

[Eric Woodbury]

ic-racer

bulb is fine. I'm not a big fan of LEDs for numerous reasons, but mostly that they don't have enough blue (contrast) in them. What people see and what paper sees is different. Going to a 250W from a 150W is not that much of an increase. I did see a nice 150W tungsten/halogen bulb the other day that fits in an E11 socket. I may try this if I can find a ceramic E11 socket. I could make a quick housing and I think I have the heat absorbing glass somewhere. I will run these errands on Friday.

[ic-racer]

ic-racer

bulb is fine. I'm not a big fan of LEDs for numerous reasons, but mostly that they don't have enough blue (contrast) in them. What people see and what paper sees is different. Going to a 250W from a 150W is not that much of an increase. I did see a nice 150W tungsten/halogen bulb the other day that fits in an E11 socket. I may try this if I can find a ceramic E11 socket. I could make a quick housing and I think I have the heat absorbing glass somewhere. I will run these errands on Friday.

Not sure I follow. 250w is almost double 150w but you don't think that will have much of an increase in output? And you found a 150w that might be twice as bright as another 150w lamp ???

Either way, it is good to experiment. I checked 6 different MR16 bulbs and two different power supplies on my kids Minolta enlarger. There was about a 2 stop difference between the dimmest combination and the brightest. So it pays to check.

[tgtaylor]

The Beseler manual for the MXT specifies a PH212 150W, 117V bulb for the condenser head and 250W, 82V lamp lamp (8108) [["230V Model 8279)"] for the Dichro 45S colorhead.

Used 35mm Mixing chambers come up regularly (I bought one last month for $10 in excellent condition) and 6x7 chambers less often.

[Jim Noel]

dsphotog mentioned the setting of the condenser.
If it is set correctly it will concentrate the light in a smaller area thus making the exposures shorter. Unless your negatives are severely over-exposed and/or over-developed there should be no need to go to the 250W bulb.
You may also be wanting to make your exposures too short. 15-25 seconds is about the shortest printing time that is practical for good control. There is nothing wrong with exposures 2 or 3 time this long.