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.

From Page 133 of Stephen Anchell’s Darkroom Cookbook

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.

Masonite primed and painted with flat black latex paint. Left (darker) side sealed with Shellac.

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.

LibreOffice rendering of interior dividers for 8×10 version of drawer.

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.

Cabinet frame showing the stair step design where the drawer front will mate to create the light trap.

Drawer frame showing the stair step design of the front panel that mates with the cabinet.

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.

The upper drawer holds two type of 8″ x 10″ paper and associated 2″ x 5″ test strips

The lower drawer holds 16″ x 20″ paper and associated 2″ x 5″ test strips

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.

Why I Did It?

When Kodak stopped producing black and white photographic printing papers, I became sensitized to the potential for my favorite papers to suddenly disappear. With Kodak papers gone, I tested other papers and settled on Ilford. But, what if Ilford stops making printing papers?

The idea of stockpiling photographic materials that have disappeared from the market is not new, but I wanted to do it in a way that assured the best chance of success, where success is defined as not running out of paper until I die. Since I was in my mid-sixties at the time, that didn’t really pose much of a challenge. I set a goal of having, at a minimum, a two year supply of paper on hand at all times. Furthermore, I wanted sizes up to 20″x24″.

How To Do It (The Research Phase)

I started this project in late 2016 and I did considerable on-line research. Unfortunately, all I have left are some notes summarizing my findings. There is not a lot of scientific testing of long term storage of unexposed silver gelatin photo paper. Why would there be when it was in plentiful supply? There is, however, quite a bit of research on archival storage of film and finished prints. In addition, I decided to conduct my own on-going tests to confirm whether I was on the right track as the years passed.

We all know that the speed of chemical reactions is reduced by lowering the temperature, so cold storage is the obvious method. Also, it’s well known that fresh photographic paper has a usable life of at least a few years at room temperature. Even old papers that have fogged can be salvaged by adding anti-fogging agents (restrainers), such as benzotriazole, to paper developers. But, I’ve also encountered paper that became fogged after only four years of storage at temps between 65 and 75F. What I was seeking is not just to avoid fog, but to maintain all the original characteristics of the paper for as long as possible.

My research discovered that, indeed, paper will last longer if stored at cold temperatures. The colder the temp, the longer it will last, at least down to 0F. Reducing the temperature has a greater impact on life expectancy than reducing humidity, but condensation must be avoided. For storage, the paper (in its standard cardboard packaging) should be placed in vapor proof laminated (Polyester/Aluminum Foil/Polyethylene) oxygen barrier bags and heat sealed with an iron. The cardboard packaging of the paper absorbs moisture at lower temps, helping to reduce Relative Humidity without drying out the product (as could be the case if desiccant packs were included).

*Freezer with Initial inventory of paper & film, vapor proof bags, and wireless cold temp thermometer.*

How I Did It

The first, and most costly step was the purchase of a freezer large enough to store boxed of paper as large as 20″ x 24″ lying down flat. That meant getting a chest style freezer. I decided against getting a frost-free freezer to avoid the temperature cycling that comes with the auto defrost operation. I do not know for certain that it would affect the paper, but since the freeze door is rarely opened and the relative humidity in the house is only about 40-60 percent, I don’t have to manually defrost it very often. I have a large low profile plastic storage container upside down on the floor of the freezer to keep the paper up off the bottom by about 5 inches making it slightly easier to reach down to the materials at the bottom.

*Paper boxes, various size foil laminate barrier bags, and humidity indicator cards*

Vapor proof aluminum Mylar bags are available on eBay in many sizes. They can be sealed quite easily with an ordinary clothes iron. Set the iron to Cotton or Wool and use it dry, so there is no steam. The sealed bags are opened by cutting off the sealed seam, but by getting larger size bags, they can be reused multiple times.

*Place the paper & humidity card in bag, squeeze out as much air as possible, and seal bag with an iron.*

I stocked up on the Ilford resin coated and fiber papers that I preferred (MGIV and Cooltone), created an inventory spread sheet, taped a humidity indicator card to each box (original packaging), and sealed each box in a barrier bag. When removing the frozen product, I always let it stand at least over night and cut the bag open the seal when it was at room temp to avoid any condensation. Preferably, I just remove the sealed bags as needed, but when a bag contained a 250 sheet box, I remove 125 sheets and refreeze the remainder for later. It’s important to label each bag as to what’s in it because the bags are opaque. I recorded the date code, paper type, size, receipt date, number of sheets for each bag, and the freeze date in a spread sheet. I also note if a package is thawed, paper removed, and then refrozen (Example: Removing a 125 sheet inner bag from a 250 sheet box of Ilford paper.)

How Will I Know If I Accomplished My Goal?

As a monitoring scheme, I placed several 8″ x 10″ sheets of Ilford MG IV RC paper (Date Code: 33C504C60, Rcvd 10/6/16) in a paper envelope, sealed the envelope in a barrier bag, and then subjected it to several freeze/thaw cycles over time, occasionally removing one of the sheets and testing it by making a 5″ x 7″ print of a particular negative with a tightly specified enlarger setup using fresh Dektol developer. Additionally, using the remainder of the 8″ x 10″ sheet, I contact print a step wedge using #00, #2, and #5 contrast filters. I compare the resulting print and step wedges against a control which was made on a never-frozen sheet of the same paper in February 2017 when I first began actually freezing paper. My latest test was done in October 2022. So far, the results have been visually identical.

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The Perfect Paper Safe