Considering a DIY enlarger made from my 4x5

[BHuij]

I'm waiting on my Intrepid 4x5 to arrive (should be towards the end of this month, or early next). Until now, I've been shooting some 35mm and a lot of 6x6, so my trusty Omega B22 that I picked up locally for a song has been fantastic.

Unfortunately, the local market for large format enlargers is pretty dead. I can find Omega D-series, Beseler 45s, etc. online at a popular auction site, but many are local pickup and most are still quite a ways out of my budget.

I know DIY options can work, and that a simple diffusion enlarger would not be terribly difficult to build. I figure all I really need is a light box with a diffusion panel that somehow easily mounts to my 4x5 camera. Modify a film holder to act as a negative carrier, mount the sucker on the bottom of my tripod column, stick a 135mm or 150mm enlarging lens on the front standard, and print on the floor.

So I'm going to design and build the light box over the next few weeks. My only enlarger experience is with condenser enlargers however. I know that the distance between the lamphouse/condenser assembly and the negative is important to get optimally uniform light across the printed image. Does the same hold true for diffusion enlargers? If so, what's the optimal distance from the diffusing panel to the negative?

Thanks in advance. I'll document my build carefully and make sure to post about it.

 

[DWThomas]

With your idea, the distance is relatively unimportant, it is the quality of the diffusion that counts. I would think having some space -- half an inch or so -- such that any dust or crud on the diffuser surface would be outside the depth of field of the enlarging lens would be a good idea. There used to be a "cold light" made that was a metal box with a folded fluorescent tube inside and an opal glass cover that could fasten onto a 4x5 in place of a Graflok back to do what you are describing. I own one, but haven't gotten around to working out a mounting column for the camera.

 

[locutus]

Hi!

I'm working on exactly the same project at the moment, what i did for now is a cardboard holder for the film which slides in behind the groundglass and a lamp placed about 40 centimeters behind also covered by a cardboard light box.

This kinda works as a proof of concept but obviously needs to be improved.

I have just bought a LED panel with a diffuser layer on it meant as a ceiling light from AliExpress and plan to build a replacement back with a place for the film holder (nothing more then a groove with some bolts on top to lock the DDS and the panel in the back.

For the lens i have been using a Fujinon 180mm f/5.6, the ~8x10 projection I see on the wall seems sharp enough to me so a enlarger lens is far down the list.

Panel: https://www.aliexpress.com/item/6W-...lgo_pvid=61e86d4a-8196-4312-907f-ef88a3f84cffhttps://www.aliexpress.com/item/6W-...lgo_pvid=61e86d4a-8196-4312-907f-ef88a3f84cff

 

[BHuij]

With your idea, the distance is relatively unimportant, it is the quality of the diffusion that counts. I would think having some space -- half an inch or so -- such that any dust or crud on the diffuser surface would be outside the depth of field of the enlarging lens would be a good idea. There used to be a "cold light" made that was a metal box with a folded fluorescent tube inside and an opal glass cover that could fasten onto a 4x5 in place of a Graflok back to do what you are describing. I own one, but haven't gotten around to working out a mounting column for the camera.

You know I read about those, and the Intrepid back is Graflok compatible. They're even fairly inexpensive on eBay right now (I believe it's made by Arista?). The reviews I read though said that the light quality from the bulb in that thing was really inconsistent, making it difficult to get good prints. What is your experience with it?

 

[BHuij]

That panel looks pretty good actually. Which size did you go with? The 12W one looks about right to me in terms of both size and light output for a 4x5 enlarger.

 

[DWThomas]

You know I read about those, and the Intrepid back is Graflok compatible. They're even fairly inexpensive on eBay right now (I believe it's made by Arista?). The reviews I read though said that the light quality from the bulb in that thing was really inconsistent, making it difficult to get good prints. What is your experience with it?

Sorry, I'm afraid I don't have any use experience with it. I picked it up many years ago with some other stuff. More recently I replaced the power cord and made some brackets to mount it on my non-Graflok B&J Press as a first step. But alas, I have never gotten around to rigging a way to mount it on something to serve as an enlarger column. I used to have a home brew column to use the camera with a different (and not terribly satisfactory) light source but it's long gone, and other than a few pinhole shots which I've scanned, I haven't been shooting 4x5 since the 1970s. If I were starting from scratch I would likely target an LED device for a light source. (With enough patience one could even do an RGB LED device with adjustable color output for VC papers. But I'm afraid that's about two miles down my current priority list.)

Sorry to not be more helpful.

 

[Ian Grant]

At least 3 companies made light sources and adapters to convert LF cameras into enlargers, the Graflarger for one, I think both MPP and Linhof made them as well.

So go for it.

Ian

 

[BHuij]

Sorry, I'm afraid I don't have any use experience with it. I picked it up many years ago with some other stuff. More recently I replaced the power cord and made some brackets to mount it on my non-Graflok B&J Press as a first step. But alas, I have never gotten around to rigging a way to mount it on something to serve as an enlarger column. I used to have a home brew column to use the camera with a different (and not terribly satisfactory) light source but it's long gone, and other than a few pinhole shots which I've scanned, I haven't been shooting 4x5 since the 1970s. If I were starting from scratch I would likely target an LED device for a light source. (With enough patience one could even do an RGB LED device with adjustable color output for VC papers. But I'm afraid that's about two miles down my current priority list.)

Sorry to not be more helpful.

No worries. The idea of using RGB LEDs is intriguing; I may play with that concept at some future point. For now I think I'm going to go with that AliBaba white LED panel and built-in diffuser. It looks just about perfect for what I have in mind. I think I could fairly easily put together a lamphouse from plywood in my woodshop, and if I'm careful in my design, I could even use the Intrepid's Graflock tabs to attach the lamphouse. The whole thing could be suspended from my tripod, and if it works as well as I'm hoping, I could eventually put together a DIY column at some future point.

 

[locutus]

I went for the 22CM/24Watt one, i plan to remove the metal wall mount on it to reduce its weight and attach it to some wood.

 

[chris77]

very interesting.. keep it up!

 

[Patrick Robert James]

I didn't take a look at the light panel, but I doubt it is going to be enough light to satisfactorily use. If you are going to make a lamphouse, then use a real bulb. Most 4x5 enlargers have bulbs north of 150 watts for a reason. Bulbs are cheap. All you need to find is some diffusion. White plexi is great for that. You should also paint the inside of your "lamphouse" white and as long as the bulb is far enough away from the plexi, the exposure will be even across the film.

Hope that helps you.

 

[BHuij]

I didn't take a look at the light panel, but I doubt it is going to be enough light to satisfactorily use. If you are going to make a lamphouse, then use a real bulb. Most 4x5 enlargers have bulbs north of 150 watts for a reason. Bulbs are cheap. All you need to find is some diffusion. White plexi is great for that. You should also paint the inside of your "lamphouse" white and as long as the bulb is far enough away from the plexi, the exposure will be even across the film.

Hope that helps you.

Actually based on a little googling, my current bulb (75) puts out about 1200 lumens, and that 12W panel puts out roughly the same. I find myself struggling with too short of exposure times much more often than too long, so I'm not too concerned about it being too dark. All the same, thanks for the tips on lamphouse construction!

 

[DWThomas]

I didn't take a look at the light panel, but I doubt it is going to be enough light to satisfactorily use. If you are going to make a lamphouse, then use a real bulb. Most 4x5 enlargers have bulbs north of 150 watts for a reason.

I think you might be surprised. Those lamps are a distributed array of emitters that put out quite a bit of light (think I saw 1200 lumens). They also have the advantage of much less heat.

 

[locutus]

Most 4x5 enlargers have bulbs north of 150 watts for a reason.

Specs for a incandescent enlarger bulb:....

3010K
2300Lumen
100 Life hours
150W consumed

LED Panel:....

3000-3500K (3100 typical)
2400Lumen
>50000 Life hours
24W consumed

I think i can see a reason why to go for a LED panel.

 

[tedr1]

I am not an expert however I believe there is an issue with the concept of color temperature and LED lights which are not incandescent and have a different spectral shape to incandescent. This matters for VC papers which are blue green sensitive and designed for use with incandescent sources. It might be wise to include in the LED version an investigation of the behavior of the VC filters and the contrast variations that can be obtained, it may differ from significantly from the nominal Ilford values. Tests are possible before the LED lamphouse is constructed, simply lay a negative and the VC filter on the paper and illuminate it with the LED light, repeat for the set of filters, see what comes out. If it is a range of evenly spaced contrast grades with the full span of contrast from soft to hard things are good


This is an example of the spectrum of an incandescent lamp, note how blue is reduced compared to green

 

[locutus]

You have a point with spectral response issues, now a bit of googleing shows quite some people have built LED sources for enlargers.

I suppose the easiest is to just try and see if we are happy with the actual prints, that is what matters in the end after all. Its a cheap hobby project (15E for a 5x4 holder, 25E for the LEDs and some scrap wood) not much to loose

 

[BHuij]

Yeah, I am actually expecting the contrast filters to perform somewhat differently than they do in my B22 which uses an incandescent light. But I'm just going to use real prints to do my testing and make sure I have a feel for what each filter does. As long as I can get end results I'm happy with and everything behaves consistently, I'm fine. Worst case scenario I can just find a different light source for the lamphouse.

 

[MattKing]

If you are worried about spectral response, do some tests with scraps of paper, VC filters and contact prints before you build a mount for the lamp.

 

[adelorenzo]

There was a good discussion over on Large Format Photography Forum about this, they were talking about 8x10 but still plenty of good information and some photos too:
http://www.largeformatphotography.i...0376-Hacking-8x10-and-11x14-enlarger-LED-head

 

[grahamp]

I have an LED light table that works as a light source for my 8x10 modification on a Beseler MX. 11,000 lumens at 4,600K gave me around 20 seconds exposure at f11 for an 11x14 enlargement of an 8x10 original (240mm lens). Now, this is a 12x12 inch unit, and I am only using (8x10)/144 of the illumination (assuming nothing is productively reflected back into the unit). That's about 6,100 lumens. A smaller format will do fine with less, so the 2,000-2,500 lumens estimate seems fair. It's a back of the envelope calculation, though.

 

[dpurdy]

I built a cabinet to use my wood field 8x10 as an enlarger. My idea was that I wanted to be able to simply set the camera in the top of the cabinet aiming down as you say. I decided that rather than raise and lower the camera for different enlargements I would I would build shelves into the cabinet that were the exact right height for full frame 11x14 and 16x20 with border and 16x20 full bleed. I built the light source by making a wooden box that would sit on top and I wired a bank of incandescent bulbs over a diffusion glass. It all worked perfectly well in that I could get stuff in focus and the lighting was even. Obviously the shelves were the last thing I put in so I could experiment and find the exact right height. In the end, because the leveling of the camera and focusing was such a PIA I decided to just dedicate the camera to the enlarger and I cut out the bellows and replaced them with black cloth. My film stage was a sheet of plate glass that fit in where the camera back fit in and then tape the film onto the plate glass. I was able to make several perfectly acceptable prints and lots of enlarged proof sheets from roll film. The problem was that the paper stage was clear down near the floor and to get down there on my knees with a grain focuser and then reach up to turn the focus knob on the camera was painful and difficult. Another problem was squaring up the camera lens stage perfectly enough to get sharp prints corner to corner but but it was possible. I still have it but haven't used it in years.

 

[BHuij]

Anyone have recommendations (i.e. links) to a good material to use for light diffusion between the light source and the negative? After giving some thought to my design, I think it makes sense not to rely on the built-in diffuser in those LED panel lights. I think the best place to add additional diffusion is either in place of the ground glass in the camera back, or at the bottom of the lamphouse (slightly above the ground glass, since this will be a vertical enlarger).

Reading around this forum, it sounds like going to the hardware store and picking up some white or frosted Acrylic should be no problem. Where I live we have Lowes, Home Depot, and Ace. Checking all of their websites, the only acrylic I'm seeing is clear, and frosted (which only comes in huge expensive quantities).

 

[Leigh B]

Graflex did this.

It was called the Graflarger, an accessory for their regular press cameras.

- Leigh

 

[BHuij]

Yes, I've looked into it. Generally speaking it looks like a bad option for getting really consistent prints, especially on the VC paper I use exclusively. Hence my decision to build my own

 

[DWThomas]

Reading around this forum, it sounds like going to the hardware store and picking up some white or frosted Acrylic should be no problem. Where I live we have Lowes, Home Depot, and Ace. Checking all of their websites, the only acrylic I'm seeing is clear, and frosted (which only comes in huge expensive quantities).

Hmm -- like so many things, stuff changes. A couple of decades back such places sold a flat sheet about 1/10 inch thick to use in 24x48 fluorescent fixtures. The stuff was smooth and white, about like "opal" glass, but acrylic (or some sort of plastic). I'm pretty sure commercial sign makers use such stuff, might check out some sign making shops. The optimist in me thinks they might have scraps big enough for what you need.