My darkroom paper safe has, for decades, been a small DIY wood cabinet with some shelves inside. I have never trusted it to be light tight, so I kept all the paper and test strips stored inside in black plastic envelopes like the ones paper and film are packaged in. The hinged door was held closed with a window latch. Although it’s large enough for 11″ x 14″ paper, I never put any paper larger than 8″ x 10″ in it. In fact, I practically never use 11″ x 14″ paper. This was no one’s idea of a perfect paper safe and I wanted something better.

The Research Phase

I wanted something that made access to the paper and test strips as easy as pulling it out of a drawer. As with all such projects, I started with research on the internet.

There is a nice drawer based design by Kenneth Wells in a 1971 issue f Popular Science.

A very attractive and practical DIY based design by Reinhold Schable can be found on FADU. In fact, if you haven’t visited Reinhold’s website, re-inventedphotoequip.com, you should definitely drop by.

Page 133 of the Darkroom Cookbook (2nd Edition) has a drawer based design that is both simple and close to what I wanted.

Construction Materials Considerations

On top of the designs by others, there is a lot of discussion on the photo forums about which materials are good for building a paper safe and which are problematic. The TL;DR of it is that you should stay away from materials that contain formaldehyde. From that discussion and my own research I learned that “engineered wood” like plywood, particle board, and MDF contain adhesives that can produce chemical vapors harmful to photographic emulsions, although there is some argument that, because of new regulations, modern versions of those manufactured products have less of the harmful chemicals. It is also plausibly reasoned that water based paints are less likely to emit emulsion-unfriendly vapors than oil based coatings.

Another possible solution is to apply shellac over engineered wood and painted surfaces to block the chemical outgassing. As an experiment, I covered one half of a painted surface with shellac to see if there was any discernable difference.

After the allowing several hours to dry, I held each side right up under my nose to see if I could smell any difference. I expected the shellac to smell like shellac and the latex to smell like latex, but the shellac side had no detectable smell while the latex side smelled as you would expect freshly pained latex to smell. Not a very scientific test, but it certainly dampened my skepticism. A downside to the Shellac is that it leaves a glossy finish (making it look darker in the picture above). I prefer a flat finish for light proofing in order to minimize reflections.

In any case, I condensed that research down to a decision to avoid those products altogether and stick with ordinary wood and Masonite (hard board) which, I was surprised to learn, is made with pressure and water, rather than adhesive chemicals. I also decided to stick with water based paint and glue and allow at least a couple months of outgassing of any acrylic or latex binders before trusting it to safely store photographic paper.

Pictures of the Project

For anyone interested in seeing the actual construction of the paper safe, I took many snapshots during the six weeks it took me to complete the construction, painting, and installation in my darkroom. You can view those pictures on my CityShadows.org website here.

Features and Design

The design requirements were as follows:

• Drawer based operation.
• No cover to lift up or slide back to access the paper.
• Must fit the space I had planned for it.
• Sized to hold 8″ x 10″ and 16″ x 20″ paper.
• Drawers should open fully, so the interior is fully accessible from above.
• Must close and stay closed reliably without a latch.
• Extracting individual sheets of paper must be fumble free.
• The project had to be something I had the skills and tools to build.

Basically, I was envisioning a drawer with a stair step front that would mate with a stair step cabinet, thereby creating a light trap. There would be two equal size drawers with dividers as necessary to create compartments for 8×10, 16x20s, and the associated test strips. I use 2″ x 5″ test strips for everything. I began the design as a LibreOffice Drawing which was fine to render the simpler aspects such as the divider layout.

For the more complex light trap features, I quickly realized that the complexity was going to need the 3D features of a CAD program, so I switched to FreeCAD which I’d used on another project. Personally, I really struggled with the learning curve for FreeCAD and am far from adept at using it, but once you’re done, you can view and rotate every piece and how they fit together. You can also see immediately if the component parts can be practically crafted with the available tools and materials.

Construction

A major part of the reason for taking on this project now was because I had recently purchased a table saw which permitted more precise cuts than I was able to do previously. The CAD program spelled out the exact dimensions I needed to achieve a gap of no greater than 1/16th of an inch between the drawer front panel and the cabinet stair step geometry. I used a caliper and test cuts to achieve that level of precision. At first, I tried cutting the stair step on a DIY router table, but it was slow going and not exact enough, so I coughed up the money for a set of dado blades for the saw. That made it about 3000% easier and more precise.

I used poplar for the main framework, but used much more rigid red oak strips as supports under the Masonite floor of the 16×20 drawer. Masonite is susceptible to sagging. The poplar dividers for the 8×10 drawer are glued and screwed to the sides of the drawer and, using screws from below, act as supports for the floor of the drawer. Since the 16×20 drawer has a large area with no support from above, I raised the floor enough to place the support strips under it. This made sense because I don’t use as much 16×20 paper, so the drawer doesn’t need to be as deep as the 8×10 drawer.

In addition to the drawer floor panels, the cabinet was entirely enclosed in Masonite panels and, because the drawer front receded into the font of the Masonite enclosure, it formed part of the stair step light trap configuration.

The “Soft-Close” drawer slides I used allowed for full extension of the entire drawer and have a feature that pulls the drawer closed the rest of the way when the drawer is pushed within a couple inches of closed. That feature actually holds the drawer closed quite securely, making inadvertent opening nearly impossible. In the quiet of my darkroom, I can tell from the “thump” that that it closed completely. I also chose rounded drawer handles that could not snag on clothing and pull the drawer open.by accident.

In order to make extraction of individual sheets fumble free, I placed a wedge behind the paper, opposite from the finder access gap. The wedge is the full length of the paper and pushes the paper out toward the top of the stack. This clever self fanning feature was copied from the Reinhold design. In addition, I placed a sheet of Masonite under the paper, but slightly smaller than the size of the paper so the paper overhangs it on the finder access side. This elevates the paper by 1/8th inch off the main floor of the drawer making it easy to get my finder under the last sheet to lift it out. I should note that, since Masonite is a dark brown, I didn’t paint the floor of the drawers. Less paint means less outgassing to worry about.

One of the last construction steps was the mounting of the front panel of each drawer. The front panels were already matched to the cabinets to fit without any rubbing that would result in the black paint being worn off. The drawer front mounts to the main drawer frame with two machine screws. I glued small pieces of sand paper, to the drawer frame, rough side out, so that the front panel would not move once the screws were tightened. Using shims in the gaps around the edges, I centered the front panel and tightened the screws. There is no rubbing of the stair step surfaces against each other. The gaps aren’t perfect, but they are at least as good as I hoped hey would be.

Installation in My Darkroom

My enlarger table is home built and I designed the paper safe to fit into a space below the counter top next to my D5 Chromega. Basically, it would reside just below the table top where my old paper safe had been setting. A fair amount of customization of the table was required. My paper safe not only had two drawers, but each drawer had its own cabinet. To mount it, I installed two shelves, appropriately spaced, and used aluminum brackets to secure the cabinets to the table legs. Because each drawer is a complete unit, I can remove either one for modification or repair without disturbing the other.

Final Thoughts

After finishing the installation, I left the drawers open for 2 months to dissipate any residual vapors. After that, I placed sheets of paper, face up, in the the drawers and developed them after several weeks to make sure there was no fogging. In actual use, I decided to place the paper face down to minimize exposure to the safelights from repeatedly opening the drawer to extract paper during printing sessions. My safelight are very safe, but reducing exposure to them is never a bad thing. In fact, I develop RC prints face down for the same reason.

Since I use Ilford Cooltone and MGIV RC 8×10 paper and Cooltone FB 16×20 paper almost exclusively, this will cover 99.9% of all my printing needs. Any other photo papers I use are stored in a cabinet in their original boxes.

Conclusion

So far, the new paper safe drawers have been working perfectly. No fogging and accessing paper is now much more convenient. Is it “The Perfect Paper Safe”? Well, maybe not, but given what I had been using, I had nowhere to go but up.