I've updated the templates for 35mm and 120 cameras and I think made improvements in function, particularly with the shutter, as well as eliminating the need for opaque photographic tape. (Although that makes a terrific outer covering of the finished camera). This link leads to new templates for a 6x6cm camera in 45mm and 60mm lengths, as well as the old 24x36mm, 24mm. and 6x9cm, 60mm cameras. They take a hair more care to make than the original, but not that much.
I've recently seen commenters on the Facebook group "Hand-made film camera," when looking at some precision rare-wood and brass beauty, wish they had the skills to make their own camera, and to be honest, a significant array of woodworking and machining tools, and a dedicated place to use them. I don't have any of those nor the skills to use them and I do all this on my kitchen table, but what I do have is some limited experience making paper models and years of experience as a graphic artist when an Xacto knife was the tool in your hand more than anything else, so that is where this concept comes from.
I don't know if there's really any need for another plan for a do-it-yourself pinhole camera on the internet, but I'm going to write the rest of this as though you were going to make one.
Measuring precisely to cut and fold pieces is extremely tedious and error prone, so the idea is to print a template on paper, glue it to some appropriate card stock, cut the pieces out, fold them and glue them together.
Make sure your PDF reader is printing at 100% or full size and not "fit to page" or things won't fit. I've set the file to print that way, but some readers (cough, Chrome, cough) don't recognize that setting. I've put a 1 inch and 25mm scale on the first page so you can check. The pages are US letter sized, but the prints should fit on A4 paper, except the 6x9, 60mm which had a part that wouldn't fit and is on 11x17 inch pages.
You'll need foldable card stock of some sort. Cereal boxes (you can get one camera out of a large economy size box, but I'd have two handy) or 24 packs of beverages in aluminum cans are good and often colorful sources. Not all combinations of your computer print and the box are necessarily going to be light proof, so if you're not interested in playing with the printing on the card stock, material usually referred to as poster board in arts & craft stores, in black, is the premium material. Remember that it has to fold so something like matte board isn't going to work. If you're not completely convinced your print and card stock is completely opaque, you can paint the interior with three or so coats of matte black paint, and I've included another option if you can't do that.
I use Aleens tacky glue, but almost any white glue for paper or wood will work. For gluing the template to the card stock, permanent spray adhesive is quick and gives a quick bond, but it's messy, and you're going to need the white glue anyway to put the camera together. Permanent glue sticks are alright for glueing the template to the card, but I'd avoid using it to glue the parts together - the resulting joint isn't flexible and parts tend to pop off.
The template, in most cases, is intended to be the inside of the camera.
If you're using white glue, make sure you spread it very thinly and completely covering the surface. Too much glue will get the paper wet. Squeegee the template down with a credit card or something. The template has to be completely attached to the card stock all the way to the edges or your camera is libel to peel apart at some unfortunately timed point. Make sure you wait until it is completely dry to continue - wet paper doesn't cut very well.
A couple parts, specifically the middle layer of the shutter, need to be stiffer so you need to laminate two layers of your card stock together to make those parts.
Cutting and folding the template
Most of the cutting out of the template once it's glued to the card stock can be done with a good pair of scissors. Obviously it's important to cut accurately. The holes for the tripod mount, winders, shutters, film counter, pinhole, and maybe the thumb grips need to be done with a craft knife like an Xacto. You'll also need some kind of cutting mat - those are available at Walgreens for a couple bucks. Don't push too hard or you'll break the tip, let the knife's sharpness do the cutting. Better several light strokes. Probably more accurate, too. Buy extra blades and change it whenever you break the tip or start feeling it getting hard to cut. You probably shouldn't need more than three blades and I've actually done it with one.
The holes for the winders should be cut a little on the small side and then use the dowels for the winders to enlarge them so they fit very tightly. Those holes are an opportunity for light leaks. Always be paranoid about light leaks. The sun is a vengeful benefactor.
Score all the folds with a ball point pen against a straight edge. When you do fold them, crease the fold all the way in both directions so the card isn't trying to straighten itself back out.
The camera body
Start with the internal assembly and the inner box.
When gluing a surface like the printing on a cereal box that's somewhat glossy, roughen up the surface with the tip of your Xacto knife. If your print is a laser print, that should be roughened too if it's the surface that's getting the glue.
Keep a damp paper towel around to wipe off excess glue.
Clamp glued parts together with binder clips. If I was buying them specifically for this project, I would get one and a quarter inch ones, but I've got a lot of 3/4 inch ones and they work all right. They sell packages with both sizes. You could also use clothes pins.
One of the main differences with the older versions of the Populist is that the boxes are held together with glued flaps instead of opaque photographic tape. With the inner box, the flaps should go on the inside and with the outer box the flaps go on the outside so you have a smooth continuous surface where they slide together (light leaks, ya know).
When the internal assembly is dry, put it inside the inner box and glue everything together. Make sure that the internal assembly is centered in the box, aligned with the lines on the inside which define the 6x6 image area, and the bottom of the internal assembly aligns with the tripod mount hole. In addition to the clamps, you can clamp the front of the box with a couple of rubber bands. You don't want to crush the box with them and make sure the corners are square and the flaps come together on the inside.
Fold the film reel spacers that hold the film up near the back of the camera and place them in the film bays. You really don't even need to glue them. (There are none in the 35mm film camera.)
In order to make sure the outside box fits tightly - ergo light doesn't sneak between the two - you have to glue the outside box while it's wrapped around the inside box. Make sure you have it fitting as tightly as possible. In order to make sure the two don't get glued together by some stray glue squeezing out, I put a bit of wax paper between them.
The two boxes should be a little hard to get apart. The thumb holes should make it a little easier to get a grip on the inside box.
The tripod mount
You'll have to use the template for several separate parts so don't glue it on until you put it on the cap at the end. (Don't cut holes in the cap!)
With this type of nut, for the bottom layer of the tripod mount, I use 3/16 (5mm) foam core so I can drive the prongs into it. It doesn't need to be black foam core since it will be covered. You could use wood if you had some that thin. If neither are available, use a square nut instead and laminate 7 or 8 layers of your card stock together to make the thickness of the nut. Make sure to cut them all and the holes before you glue them together, because you're not getting through that stack with an Xacto knife, and put the nut in there when you glue them together.
Here are the four parts of the tripod mount. When glued together, glue it to the bottom of the camera. Notice the hole is not in the center. The wider side is toward the front of the camera, so there's a gap toward the back so it doesn't block the image getting to the edge of the film. Clamp it. If you don't have a big enough clamp, put some rough holes the t-nut will fit through in a few layers of card stock. With those between the camera and the tripod tighten it on the tripod. You will want the cap on this to be matte black (the template, paint or Sharpee).
The shutter is a three layer sliding shutter. The middle layer, which includes the actual moving shutter should be made with two layers of your card stock laminated together with glue to make it stiffer so it doesn't bend when you open and close it. This is probably the fiddliest part to cut. It's probably a good idea to have a steel rule to cut against to make sure your cuts stay straight and use a new blade and go slow with several strokes. Let the knife cut because it's sharp.
Here are the four parts of the shutter (Well, seven, the shutter handle is made from three pieces). This is the film counter shutter. It's got a round hole. The front shutter has a square hole. 35mm only has one shutter.
This is a moving part so when you glue it together you have to be very careful not to glue it into immobility, yet it's important that it doesn't come apart. Remember to roughen shiny surfaces, be careful to use enough but not excess glue, spread the glue into a thin layer, leave a little gap near the inside channel where the parts move, and clamp immediately, but position them so the shutter still moves.
I always move the shutter right away after putting the clamps on and move it every several minutes until I'm sure I haven't glued it in place.
Once they're dry glue them over the corresponding holes on the camera and clamp them with several rubber bands. Make sure you don't glue the shutter in place!
You'll need a 120 reel or 35mm cassette at this point. You used to be able to get handfuls of these from photo labs which were in almost any city. You can buy them from photo suppliers (You're probably going to have to get the 120 film by mail order anyway). And you might have one of those lensed cameras that takes 120 and you already have lots of them.
I use two winders so that if the film gets a little crabby about moving you can loosen the supply side and then tighten the take-up side, and I recently accidentally wound past the number with a single winder camera. With a second winder you can just roll it back.
The 35mm winders are slightly different. Refer to the original Populist instructions.
The winders are made out of 3/8 inch dowels. which are probably 10mm outside the US. If you had to buy one I'd get oak since it's the strongest option, but I've used anything I can get my hands on. The previous owner of our house left a stash of dowel sticks that had been used as the handle for little flags people wave at parades that I used for years.
I do this with a really cheap little coping saw, but I have done it with a keyhole saw, mitre box saw, a dremel tool, a hack saw and even a full size cross cut saw once.
I use a 30mm piece and draw a line around the circumference 6mm from the end. I then hand draw where the tab will be on the end of the dowel. I always like to err on the wide side and then whittle it down to fit into the slot with my Xacto knife or a pocket knife.
Holding the dowel in a vise-grips or pliers, I start the cut with my finger guiding the saw. Make sure you keep the cut vertical and cut exactly to the 6mm line. It's better to have both shoulders at the same level.
Then turn the vise-grips, line up the cuts you just made parallel to the table, and cut down the 6mm line. Be careful to stay level and stop before you cut into the tab you're trying to make.
Then, as I said, whittle to fit. You want them to insert all the way into the slot, and they should be a little tight.
Then with the 120 reel in, with the boxes together, insert the winder so it's fully seated into the slot, and draw a line around the winder which will only be a millimeter or two from the shoulder
Whittle a shallow groove where the line is to give the glue somewhere to grab on. Apply glue around this groove and slide the winder collar on, black side down, so that it's exactly aligned with the groove. You want that collar to sit right on the top of the camera. If the hole in the winder collar is a little tight, you might feel it catch the groove. Make sure any excess glue on the bottom is wiped off so it doesn't dry into little bumps.
Now, if you're not really confident your print and cardboard combination is truly opaque, is the time to add a little additional barrier. The easiest and I think a very effective way, is to paint it with three or so coats of matte black paint. If you want to preserve the design on the outside from your cereal box, you should probably use some masking tape and paper to cover that. Not a bad idea to paint the outside of the inside box from about the middle to the back to make it harder for light to get down that way. If you can't do spray or some other paint, I've included a template for another layer for the 6x6 imaging area in the front, and the entire back of the camera. Everywhere else you've already got several layers. You might as well use a layer of your card stock as well for this additional light proofing. Remember everything on the inside of the camera has to be black. You could blacken the sides of the inner box with a Sharpee.
The film rides over the folded edge of the internal assembly which could be a little rough. Cover that edge with something smooth like black tape or glue a bit of old black T-shirt over it. Make sure you glue it flat so it doesn't get in the way of your image.
I'm not going to give directions on how to drill a pinhole. I'll link to a post I did about pinholes earlier and a second one. Both have a cursory set of directions on how to drill and measure a pinhole. To measure really accurately you'll need a flat bed scanner. You might be able to do it with a microscope attachment for your phone camera. If you don't have a way to measure it, do your best and just try it out and you'll probably be within a stop. If you end up too overexposed or your images are too blurry, try again. It's easy and cheap.
The optimal pinhole size is .2mm for a 24mm camera, for a 45mm camera is .28mm and for 60mm is .33mm. The F ratio is going to depend on the size of your pinholes, but with the ideal pinholes on these it's f116 for the 24mm camera, f159 for the 45mm, and f183 for the 60mm.
In any event, tape the pinhole on the inside of the camera. If your tape isn't black, blacken it or cover it with the light proofing layer. You can leave a little shiny metal around the pinhole, but minimize it.
Glue the viewfinders on the top and sides of the camera. I like a little bit of 3D in my view finding lines and find it worthwhile to put the viewfinder on a layer of card stock.
The winder minder
There's really nothing but friction holding the winders in, and losing one will probably result in a light leak on your film. (If you do lose one with film in the camera, put a piece of black tape over the hole, and wind it in subdued light with a key) The winder minder slips over the winders and holds them on and is itself held on with two rubber bands.
Advancing the film.
Film advance should be smooth if you've gotten the film bays the right size. If the film gets a little sticky, loosen with the supply side and then take it up with the take-up. Make sure the winders are both tight or you might have a bit of curved film inside the camera. By the way, it shouldn't make any difference which is the supply side and which the take up, but if you put the supply on the right, the numbers will be right-side-up in the film counter window. For film loading and counting in the 35mm, refer to the original Populist instructions.
If you're mounted on a sturdy tripod and coordinated enough, advancing with both hands turning the winders at the same time is particularly smooth.
Then you go out and take pictures.
Paper cameras are not waterproof, and paper doesn't wear well, but I've got one that is covered in opaque black photographic tape that I've had in my pocket for 10 years.
Gregg Kemp had a strong preference for Pinhole Day images that were made on film with homemade cameras. You've still got six weeks to get it done. It probably takes about 4 hours work, but there's a bunch of times you have to wait for glue to dry, preferably overnight.
Have fun. Let me know of any comments or questions. I'd love to see pictures.