Humidor for Paper?

We all know that dampening your paper can make your printing extra nice.

Printers in dry climates (like us in Colorado) also know that dampened paper can be totally bone dry by the time you get through 50 prints. It can also be tedious to spray each sheet of paper, especially for a long run.

So I thought… why not construct a humidor for paper? One could cut your sheets down, stick them in the humidor over night and take them out in stacks of 20 as the run progresses. Does this sound totally insane? If not, any thought on how it would work? My dad has several humidors, perhaps I should ask him :)

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Actually, that’s not insane at all. I’ve seen several humidor-style set ups through the years. Essentially, they were plywood boxes large enough to hold the required paper, varnished on the inside, and a moisture supply of some sort. Most commonly, this was a bundle of cloth that was kept wet.

However, the humidor might be great for keeping the paper moist…. but it is not so good for establishing the initial moisture level. If you just set a stack of paper into the humidor, it will soak in from the edges and tend to buckle the paper. The outer portions will be moist while the inner portions will be dry. This is not good.

The proceedure we use is to apply water to every third or fourth sheet with a paintbrush, and then stack them up for a day or so. It’s a lot faster than trying to spray them with a spray bottle.

You should be able to maintain moisture in a sheet with a humidity controlled environment, but you won’t be able to do much to change the starting point of the paper in a stack. As Cat points out, you may introduce some moisture at the edges but that will surely curl your sheets up.

You could put the sheets in a drying rack in a humid environment and leave overnight.

As for the humidor idea, I’ve seen factories that use a plastic sheet to make a room sized enclosure and just turn on a humidifier inside. That’s cheap and it works!

Let us know if it works.

There’s a beautiful illustration of a paper humidor on page 52 of Lewis M. Allen’s book, Printing with the Handpress. My resident woodworker scowls every time I show him that picture, so, as a hobby printer, I’ve been using a large plastic storage box with a hinged lid. I put a sheet of wet foam rubber on the bottom. Over that I put a baking rack, and on the rack I put a sheet of Plexiglas. The paper gets stacked on the Plexiglas. For multi-pass printing, I make two stacks. It works pretty well for one- or two-day jobs. Mr. Allen uses two boxes, and he says he can leave paper in them for 8 to 10 days.

This hasn’t been my experience. I’m thinking about printing a seven-color broadside, which I’d need to do over several days. Just to see what would happen, I put some properly dampened paper in my plastic humidor for a week, and it got way too damp. I think I’m going to get a hygrometer and experiment with the humidity level, adjusting the dampness of the foam rubber and maybe adding some vents. Since the broadside requires some close registration, I may go nuts if the level of dampness is unstable. I may decide to print it dry. :-(


Barb- close registration with dampened paper varies greatly, depending upon the paper. I’ve done a number of 12 x 18”, 3 and 4 color jobs on dampened Canson’s Edition that held to +- 1/64” or so across the entire sheet….. which was fine for what I was doing. Other papers have expanded, contracted, or otherwise changed size so badly that 1/8” at the tail end was the best I could achieve.


The Allen method is the only way to go (both the humidor and the instructions. All you have to do is look at the Allens work and enough said. When following the instructions DO NOT deviate or invent short cuts and you will be more than very fine.

If you use moldmade or handmade paper you should not experience registration problems. Any paper with a strong grain though, will likely drive you mad.

Here’s a pic of humidors I use that are based on the Allen design.


Short of constructing a humidor, there are quick and/or inexpensive ways of dampening paper. Depending upon the press you’re using, the easiest way is to pass a sheet of paper back and forth in front of a $15.00 humidifier set next to the feedboard of a hand-fed press. Another inexpensive way is to quickly immerse every sixth or seventh sheet of paper and stack it on top of the other six or seven sheets, building a stack of 100 or more sheets. Place the stack(s) in a ziplock or plastic garbage bag, close or seal, and then weigh down with a medium-heavy plane surface such as a glass baking pan or something like that to keep the papers from warping. The next morning the moisture will have transferred to each sheet. You may have to experiment to find the best amount of moisture for your particular paper, but as a first venture into dampening paper the results are worth the small bit of effort and delay.