Another question about a DIY LED enlarger head

**Ulophot** · 14-Apr-2020, 10:59

I'm not a builder and have no clue about electricity. That said, I continue to wonder how difficult it would be to make an LED enlarger light source to replace my round cold light whenever it dies. I mean a simple, non-color-changing, diffusion light source. It could either fit in my current D2 enlarger housing or a rectangular fixture could be made to attach similarly to the head.

On the SuperBright LED site there is an 11x20 inch cut-able LED sheet, available in 12- and 24-volt DC. If this, cut down, either round or, perhaps, somehing like 4.5x5.5 inches to cover 4x5, supplied enough light, would it not be fairly simple to stick it to a backing board, space it from the diffuser, connect it to a voltage something (transformer?), and then plug this into the enlarging timer? Has no one made one because the lumens are not sufficient, or am I missing soemthing big here? Oh, well, a voltage stabilizer would have to be in line somewhere to maintain constant light output. Is that expensive? I'm seeing about $50 for the sheet (which could supply more than 5 such sources, plus the voltage stabilizer, etc.

I know folks here use the SuperBrights for safelighting. Can anyone answer my question about brightness, connections, etc.?

**aclark** · 14-Apr-2020, 11:15

I don't know anything about the LED sheet which you describe, but I changed my home-made 5x4 enlarger head from fluorescent light to LED by fitting four LED bulbs above the diffuser. These were pearl, and the LED equivalent of old 75watt bulbs. 2700K, i.e. warm white. This is important if you want to utilise the full contrast range of Multigrade filters. These give a bright light, they give off no heat so I can use a glassless negative carrier, and the bulbs instantly reach their full brightness.

Alan

**malexand** · 14-Apr-2020, 14:14

Several years ago I used LED strips from superbright to build a new light source for my Durst. I've been very happy with it.
Those sheets look like it would be even easier!

**Peter De Smidt** · 14-Apr-2020, 14:19

Maybe something like this: https://www.amazon.com/TX-Aluminium-...8&sr=8-12&th=1

Plus maybe this: https://www.amazon.com/Parabolic-Ref..._t4_B01D1LD682

**Ulophot** · 14-Apr-2020, 16:42

Maxeland, have you already posted what you did? Others have shown their work, and/or detailed how they did it, but the one's Ive seen required expertise, tools, etc; hence my questions. I would be very interested to know more, here or by PM, about what enlarger you have, what you had to do about fitting, connections, etc., etc. I'm sure others would be, too. Cold light is going to be replaced by LED, I believe, before long, i.e., since the cold lights tubes are not being made any longer...

**Ben Calwell** · 15-Apr-2020, 06:24

If you don't want to build it, I believe this might work on a D2:
https://intrepidcamera.co.uk/product...d-enlarger-kit

**malexand** · 16-Apr-2020, 07:13

Originally Posted by Ulophot

Maxeland, have you already posted what you did? Others have shown their work, and/or detailed how they did it, but the one's Ive seen required expertise, tools, etc; hence my questions. I would be very interested to know more, here or by PM, about what enlarger you have, what you had to do about fitting, connections, etc., etc. I'm sure others would be, too. Cold light is going to be replaced by LED, I believe, before long, i.e., since the cold lights tubes are not being made any longer...

I did a LED conversion on my Durst S-45 - a version of the 138. I picked this enlarger up 25 years ago from university surplus (I think it was $50). It did not have any condensers and I could not find them readily at the time (pre e-bay), so I tried to build a diffusion head. My first attempts with incandecents were not very good. But when LEDs took off, I was pretty sure this would be the way to go. Eventually I found some others online doing similar conversions and combined many of these ideas.

As I usually use Multi-grade papers, I chose RGB strip lights https://www.superbrightleds.com/more...24v-ip20/5148/ . I cut and soldered short strips to form a small panel to fit in the top condenser slot and a piece of frosted glass in the lower slot. If you don't have soldering experience, Superbright sells clip-on connectors instead. I have read about LED Strips wearing out quickly or being unreliable, but so far I have not had any issues going on about 2 years now - though I am not a high volume printer.

Unfortunately the controller I used doesn't appear on their site anymore - it allows you to dial in 0-255 levels for each color with a numerical digital readout. This is a simpler version with analog dials... https://www.superbrightleds.com/more...immer/117/526/

It will retain all the values in memory when switched off. There is a slight startup delay of perhaps 1/4 sec, but it seems fairly consistent and I haven't seen any issues in my prints - might also be the power supply I'm using.

However, in my testing the contrast levels of the Blue v.s. Green light on MG paper, I was underwhelmed by the supposed high-contrast of the blue light in the RGB strip. It seemed maybe a grade 3, maybe 3 1/2 max. After researching what wavelengths were actually needed for the multigrade layers, I found a single color "pink" LED strip at 440 nm https://www.superbrightleds.com/more...24v-ip20/5141/ . This is very close to the Ilford MG high contrast layer peak - also visually it looks similar to the #5 magenta MG filters many of us are familiar with. I have read others have had success using "Royal Blue" LEDs but I could not find them in a strip form - at least not from the supplier I am using.

I added Pink strips in between the RBG strips of my panel and wired it to the controller in place of the red from the RGB strip, effectively making a Pink-Green-Blue light panel. I can dial in levels of Pink, Green and Blue combined but often just use them individually for split-filter printing. I also wired the Red to a simple on/off switch so I can still use the Red for positioning the easel.

Superbright generally lists the compatible power supplies towards the bottom of the pages for each type of LED selected, and also have DIY / tutorial pages in their blog pages. If you are looking at doing white light you wouldn't need anything nearly as complex as what I did. Single color white light strips or panels would only need an appropriate power supply, plug it into your timer and you should be good to go.