Using off-the-shelf LED bulbs in an enlarger

[Paul Glover]

I've been doing a little experimenting with using a standard 60 watt replacement LED bulb in place of my enlarger's PH140.

It took a bit of choosing to find a bulb which would work. Not all will provide even illumination and there are some with power-on and -off delays. Also, it was necessary with my condenser enlarger to make some kind of arrangement for placing the bulb correctly while allowing its heatsink cooling to work well enough.

I've run a few tests and am pretty happy so far (especially not having to worry about negative pop any more!), but have yet to print "for real" (plans for that got sidetracked over the weekend but I might get some time later tonight). I did a test with grade 2 filtering and found contrast was reduced, but then exposed a couple of contact sheets without any filtration and their contrast seems fairly normal. I haven't tried green/blue filtered split printing yet.

Anyway I wrote the process up in 3 parts, in case anyone might find it useful.

http://www.paulglover.net/20140108-...ghtsource-part-1-investigating-possibilities/

http://www.paulglover.net/20140207-...arger-lightsource-part-2-a-custom-lampholder/

http://www.paulglover.net/20140211-...3-contrast-exposure-and-coverage-comparisons/

 

[Simon Howers]

Paul, my experience is that this works well. I converted a 10x8 camera into an enlarger and used a 12" square LED ceiling lamp panel as the light source.
Simon

 

[Kawaiithulhu]

Paul, my experience is that this works well. I converted a 10x8 camera into an enlarger and used a 12" square LED ceiling lamp panel as the light source.
Simon

Did that work out well with VC papers and standard contrast filters? I've been considering doing something similar with 4x5 and find this encouraging

 

[Paul Glover]

I was pleasantly surprised how well it works, seemed *better* than the original spec bulb in several ways.

One thing to be aware of with this is making sure your timer (if you use one) will safely drive a low-wattage device like these bulbs. I have an old mechanical relay based timer which has no problems, but I recall reading on a thread about LED safelights that some timers (triac based switching?) may not work.

 

[summicron1]

freestyle has standard incandescent bulbs specially made for enlargers for about $7. The biggest difference is the little circle with the wattage is on the side instead of on the top so it doesn't print down onto your pictures.

They last a long time. Stock up now, let your heirs worry about replacements.

 

[pstake]

Glad to hear about your success. That's encouraging. The write-ups are great and detailed, and the photos help illustrate.

I have a 4x5 enlarger designed to use a CLEAR PH211 bulb, which is rare as hens teeth. Opal ones are available but not clear. Fortunately the one in it still works. But I've been doing some research for when it finally croaks, and considering an LED replacement.

My enlarger is diffusion type, has a large ground-glass plate between the bulb and the negative stage.

Do you think I'll need to be as discerning about bulb selection as you were with the condenser?

My main concern has been light temperature and bulb size. I need an A21 size bulb. The LED bulbs I've found with ~3,000 k seem to run about $50-$60.

 

[Simon Howers]

LED ceiling panel

Did that work out well with VC papers and standard contrast filters? I've been considering doing something similar with 4x5 and find this encouraging

I tried this setup out with a set of Ilford filters and it does work. I would certainly suggest running some test strips because the light source is different to halogen and I found the filters behaved a bit differently. I used Ilford MGWT fibre based paper.

I can email you pictures of my setup which is based on a Deardorff 10x8 and runs horizontally on the bench, if you're interested. I've never been able to crack getting pictures into the forum!

Good luck!
Simon

 

[Paul Glover]

freestyle has standard incandescent bulbs specially made for enlargers for about $7. The biggest difference is the little circle with the wattage is on the side instead of on the top so it doesn't print down onto your pictures.

They last a long time. Stock up now, let your heirs worry about replacements.

Availability really wasn't the issue. I have 3 PH140s in my enlarger stuff drawer right now, one which came with the enlarger and two which cost about $6 combined.

Negative pop, on the other hand, was really starting to bug me. $10, plus some stuff I had to hand and a couple of hours of my time, work out a good deal less than replacing all my negative holders with glass ones and buying a (really not very easy to find) heat-absorbing glass.

Plus curiosity if it would work at all. ;-)