DIY Writeup: <$35 Lamphouse to use Intrepid 4x5 as an Enlarger

[BHuij]

Because I'm still on the lookout for an Omega D series or Beseler 45 to pop up locally at a good price, I did a bunch of research and eventually settled on building a "Graflarger" style back for my Intrepid 4x5 that I could use in the interim. Figured I'd share since I'm actually getting surprisingly excellent results.



Shopping list:

• 1/4" x 8" x 48" Baltic Birch Plywood - $9 (couldn't find it on their website, but I got it at Hobby Lobby)
• Standard E26 base socket adapter for bulb - $2.27 - Link: Lowes
• Sign White 40% Acrylic Sheet - $20 shipped - Link: TAP Plastics
• Tin foil - FREE - Ask your mom for some
  
• Some mat board to use as a negative holder - FREE - I used scraps

The lamphouse itself is just a box I carefully measured and then glued up. It has grooves on the outside so it can clip into the back of my Intrepid camera using the Graflok clips, and I mount the whole monstrosity on a tripod and print on the floor, although if you're confident in your Graflok clips you could conceivably use this setup to print horizontally onto a wall (I haven't tried). If you want to build your own, I have made an Imgur album that has all the pictures and measurements you should need to make the right size box, here.

I drilled a hole with a diameter of 1 1/4" with a spade bit and filed off a bit of extra so the bulb socket could fit snugly into the box. I just use a cheap extension cord to plug my bulb socket into my enlarger timer, but you could easily use a different adapter that has some cable and an in-line switch built in, like this one.

The box has two slots cut into it, for inserting a diffusion panel and the negative carrier. My Mk I prototype used a smaller E26 base 60W incandescent bulb and a piece of 1/8" plexiglass cut to size and sanded on both faces down to 220 grit for an even surface. It sucked. It wasn't bright enough resulting in super long exposure times, crazy low contrast, and the diffusion was only slightly more even than if I left the plexiglass clear. Even though I dodged the hotspot created by the bulb for the entire exposure on my test print, I still ended up with an obvious bulb-shaped dark spot on the paper

With the Mk II, I switched out the plexi for "40% sign white acrylic," which is specifically designed for neon lights and backlit signs. I also increased the height of the lamphouse by several inches to put more space between the bulb and the diffuser, and lined the walls around the bulb with tin foil. Looks very trailer-park-esque, but I figured I don't have to look at that ugly part of the box too often . I am now using a 23W (100W equivalent) CFL bulb. Yes, the spirally kind. I know, heresy. I was going to just use it as proof of concept until I could order a 150W enlarger-specific bulb from B&H, but I don't think I'm going to change it out unless I start seeing unevenness. So far this design works so well at diffusing the light that I can't see any unevenness in the negative, projection or print, and 100W equivalent seems bright enough for my uses. Besides that, this bulb stays a lot cooler, which is nice when I need to take time to get really critical focus.

I cut down my contrast filters to 4.25x5 and I just slap them on top of the diffuser panel before inserting it carefully into its slot. Not a super elegant solution, but it does work and I don't have trouble getting the contrast I want.

I also don't have an EL lens longer than 80mm, since before I got my 4x5 I was mostly shooting 6x6 and printing on my trusty B-22. Probably will buy a 150mm EL lens at some point since I do intend to buy a "proper" enlarger when I can make it fit my budget and a good one pops up locally. But I've been pleasantly surprised by the results from my regular 150mm Sironar S taking lens. I'm stopping down to about f/16-f/22 for my prints to compensate for not having a flat field, but so far my prints seem sharp corner to corner. We'll see if that holds up in bigger enlargements.

Bottom line, I'm extremely pleased with how well this setup works, especially considering how cheap it is. It's a great interim for me and doesn't seem to be giving me any less quality in my final results than I would expect from an actual purpose-built enlarger. It's just not as convenient to use.

Scanned 8x10 print (Ilford MG FB Classic Matte) of the first photo I ever shot with my Intrepid 4x5, done with this lamphouse + my Intrepid enlarger this morning:


Full resolution version of the scan (600DPI on my cheap flatbed) so you can see all the juicy detail. Far as I can tell, not having a flat field lens isn't stopping these prints from being awesome sharp.

If anyone builds it, I recommend keeping the following things in mind:

1. Shooting this thing on a tripod works, but keeping stuff level is a royal pain, especially when you have to use tripod legs to extend your height. Immediately before putting paper in the easel and actually exposing it, I always pull out my iPhone, place it on top of the box, and use the compass app set as a level to make sure I'm flat. I carefully check my front and rear standards to make sure they're true and don't have any tilt/swing going on. I'm sure the tolerances on the iPhone level aren't all that tight, but so far I have not noticed any prints that were off axis enough to be noticeably less sharp anywhere.
2. This thing leaks, nay, spews light everywhere when the lamphouse is on. Even my glue joints glow red. My current solution is to toss a dark towel over everything before exposing. Since I'm using a CFL, heat hasn't become an issue yet, YMMV if you use an incandescent bulb. So far no visible fogging on my prints.
3. The negative carrier is serviceable, but far from optimal. I may experiment with CADing up a model to 3D print if I get tired of the matboard sandwich. Heck, I might just buy a couple of pieces of ANR glass cut to size and tape hinge them. If I do make improvements here I'll come back and post about them on this thread.

 

[LarsAC]

Great job. Would be a nice kickstarter extension to the camera.

Lars

 

[grahamp]

Light leaks on the joints: glue some foil into the inside of the joint, or fix an opaque strip over the outside. If the leak is around the negative holder, try a cloth 'apron' or similar.

Way back, either here or the Large Format site, there was a series of posts from someone who built an enlarger for 5x4 based on adjustable shelving rails. Enlargement was in steps of about 1" vertical, but the whole thing was mounted to the wall. It took some time to get everything level, but it was solid

It looks like a well-considered project, and you now have a better feel for the benefits of enlarging.

 

[Neal]

I like it.

 

[Kilgallb]

I use my focus cloth on my home brew Light for my beseler. It keeps the stray light in check. If the fluorescent does not dim fast enough try an LED Lamp.

 

[grahamp]

In this case the lens being used is the camera one, so switching the shutter to B and using a locking cable release can factor out the bulb delays. Wait a second or two for warm up, and don't worry about fade at the end.

 

[BHuij]

I thought about using the Copal shutter as my "timer" instead of just turning the bulb on and off, but so far the warm up/cool down periods on the bulb aren't negatively affecting my print quality. I guess my process isn't scientific enough to be thrown off by these factors

 

[Rick A]

A couple of issues with using a CFL bulb. First would be "after glow" when the bulb is turned off they glow for several seconds. That's the number one reason I never use fluorescent bulbs anywhere in my dark room, causes paper fogging, and possibly film fogging if you don't wait long enough after lights out. Second, short duration "on and off" cycles burn out the starters on these. CFL's are designed to be turned on and left on for longish periods of time. Using for short bursts to print will severely shorten life, then it's in the dumpster. Standard incandescent or LED lamps would serve better.

 

[BHuij]

If I start experiencing issues with this CFL then I will try an LED. But so far I'm happy with my results and don't have fogged film or paper.

 

[elerion]

If I start experiencing issues with this CFL then I will try an LED. But so far I'm happy with my results and don't have fogged film or paper.

Great. Good job. I'm curious to try something like this.

As a note, I replaced my enlarger's incandescent bulb with a LED one. The results are good. I didn't do very detailed tests yet, to see if the slightly different color temperature or its light nature affects contrast. But I've been using it several months, sometimes printing grade 1, others grade 5, most of the time 2 (with filters, not fixed grade paper). Overall, I didn't notice any drawback yet. I think it is 4000ºK. Will check it if anyone interested.

 

[Jerevan]

Way back, either here or the Large Format site, there was a series of posts from someone who built an enlarger for 5x4 based on adjustable shelving rails. Enlargement was in steps of about 1" vertical, but the whole thing was mounted to the wall. It took some time to get everything level, but it was solid

Here it is, from LFPF: http://www.largeformatphotography.info/forum/showthread.php?19820-Fired-up-my-homebuilt-enlarger

 

[paul ron]

if after glow is a problem, just close your shutter after each exposure and problem solved.

NICE JOB!

 

[brazile]

I built a copy of this since I had an extra Intrepid lying around (long story) and am greatly enjoying the results. Thanks for sharing the details.

 

[BHuij]

I built a copy of this since I had an extra Intrepid lying around (long story) and am greatly enjoying the results. Thanks for sharing the details.

I'd love to see your results!

 

[brazile]

Maybe this weekend...!