Wednesday, July 19, 2017


I have not been a fan of the lumen print. Let's just get that out there. If you are, then keep reading (spoiler alert: I am now). Recently, over on Filmwasters, there was a discussion of the 'Lumenbox' which is a box camera designed with lumen printing in mind. But I'm getting ahead of myself. What is a lumen print? For that matter what is a lumen??


noun physics
the SI unit of luminous flux, equal to the amount of light emitted per second in a unit solid angle of one steradian from a uniform source of one candela.

I'll wait while you go look up "steradian"... Now that that's out of the way, lumen printing is simply the process of using regular black and white photo printing paper as a print out paper (POP) medium. That means you get a negative without using any chemical developer. Now in this case that may not be strictly true, but we'll get to that in a minute. So why the turn around on lumen prints James?? Well, I have really only ever seen contact prints of leaves and flowers done as lumen prints. I have nothing against leaves and flowers, but the lumen contact prints just didn't appeal to me. I don't have a good reason, it's just "because". Back to the Lumenbox camera. This guy put a simple meniscus (single element) lens on the front of a box and put a piece of photo paper in the back. He did this all in daylight, knowing that the paper, without being developed, is not very light-sensitive. He pointed his camera at something stationary for 15 minutes and pulled out a photo! Now I was a little intrigued, but not enough to buy one of his cameras... just interested. Then on Filmwasters, the people were discussing the camera and lumen printing in general and who else but Joe Van Cleave posted a couple of videos (vid 1 and vid 2) about some experiments he did with this method and his own little box camera. That really piqued my interest, especially the idea of integral developer (developer embedded in the emulsion of the paper). He and the Lumenbox guy both took the image using wet paper. The idea there was to wet the paper first and then expose it and the water will allow the integral developer do its thing while the exposure is taking place. To me that seemed overly complicated and potentially messy, especially as in vid 2, Joe puts a wetted paper into his Speed Graphic. That's a risk I'm not willing to take. So I thought if the developer is there, then there's no real reason it has to be 'activated' during the exposure. The light is doing its thing to the silver halides and the developer can wait, just like with any expose/develop process. The integral developer is intended to speed up processing, not raise the effective ISO. So it shouldn't matter when you wet the paper and activate the developer. So my thought was to expose the paper dry, then dunk it in some water to let the developer do its thing. So that's what I did. I cut a piece of paper down to 4x5 and put it in a film holder and put that in my Speed Graphic. Then I set the aperture wide open to f/4.7 and put the shutter on 'T'. Then I pointed it at a ponytail palm on my patio that sits against a white wall and left it there for 20 minutes.

I scanned and inverted the dry paper right out of the camera and got this:

That's not bad! It's a little blue, but if you don't like that it could be desaturated:

So then I thought I would try some alkaline water to really get that developer kicked in the acid! I put a pinch of washing soda (pH 11!) in some water and dunked the paper. I could immediately see things starting to happen... Bad things!! There were blobs and streaks and uneven shading and, well you get the point. The integral developer had either already reacted with something else, or was breaking down in some unpredictable way. But this was the result.

At this point the negative is destroyed, but I figured it was worth one more experiment, so I put it into some paper strength fixer (Ilford Rapid Fix 1:9). I will save myself the time of uploading it and just say it didn't help. It might have lowered the contrast a bit, but the blobs and streaks were still there.

So there you go. Lumen printing in a large format camera. I suppose you could try doing optical prints from the negative produced, but it probably wouldn't work. The negative isn't dense enough to really block any light and the light of an enlarger would probably fog the negative during the process. But don't let me discourage you if you are an experimenter. My idea here was to expose dry and then get it wet to 'develop', but what I learned was that there really isn't any need to have any aqueous involvement at all. The dry lumen print stands on its own. I hope this is informative for someone. If you see some glaring error in my logic or process, please leave a comment and we can all learn together.