Monday, January 1, 2018

Building the Pinhole Lab Camera

My fantasy pinhole lab class is a liberal construction of objectives from Art, Science, Shop, History and Zen.  Making the camera involves almost all those categories.

Link to the original Pinhole Lab Camera description     Link to Templates page

I had shop class for a semester in 8th grade. We learned some machining - drilling, turning metal on a lathe, cutting and bending sheet metal, soldering, taps and dies  - and even individual lessons in welding from the teacher.  I think an 8th grader should have no trouble making this camera.  Even before 6th grade I remember a rainy day on vacation at Christy Lake that I filled making models of the locomotives from The Great Locomotive Chase that were printed on Cheerios boxes and cut out with scissors and glued together.  I also made models of rockets and cars about that age.  This isn't really much harder. Probably the most difficult part is the need for neatness and accuracy.

I think of this as constructing the camera from raw materials. It's all paper, glue, cardstock, a little bit of brass or aluminum and a bit of tape, some of it opaque.

The camera is built from gluing a computer printed template to card stock. Designing your own camera would be a kind of an advanced class and I intend this for pinhole rookies or anyone who wanted to do this kind of experimenting.  I worked for my father for five months in a plant that fabricated feed and fertilizer mixers from raw steel.  My job was often to cut out parts from sheets of #10 steel with a nibbler or acetylene torch that had been traced around tin templates with a soapstone marker, which were then rolled or folded and welded together. This is remarkably similar.

I've made the template on tabloid paper, but I think it will fit on A3.  There are several copy businesses in my town that provide tabloid size printing. With a little encouragement, I could set it up to print on letter size.

The card stock normally found in cereal boxes and beverage containers is the material I try to use the most. The parts just fit on a large economy size box of Cheerios. The largest piece requires a 12 and a half inch square. You might need two boxes if your boxes are a little smaller and you might find the parts will fit on smaller boxes once you flatten them out.

If you can't get big enough cereal or beverage packaging, card that is often sold as poster board is usually available in 22 x 28 sheets in department and drug stores.  Get black, although if you paint the interior of the camera with a couple coats of black paint, it really doesn't matter what color it is.

The first step is to cut out the template parts with about a quarter-inch (5mm) border around them


Cut Front-1 and Front-2 right to the edge that's labeled A and B.


Arrange them on your card stock to see how everything fits so you don't have the last part hanging off the edge. Don't worry about going across folds in the original box.  That won't matter when the camera is glued together. Try to keep them square though.



Glue is a basic component of this camera, and requires a bit of care and technique. Also in 8th grade, I had an Art class where we made sculptures by gluing tooth picks together.

You can make the camera with the printed side in or out.  The template is glued to what you choose to be the inside.  I'm going to make the plain brown side the outside because I think things show up better in the photos I'm showing you here.

The printed surface on packaging is quite glossy and requires being roughened in order to give the glue something to grip on to.  When I've got a lot of area to cover,  I do this by rubbing it with sandpaper.  I'm using 150 grit because that's what I happened to have, but you could use something a little coarser if you had that. In the final template, I have made the parts of the template that will be a glued surface light grey (so there's plain white paper between the dots), but a pass with the sandpaper over those areas wouldn't hurt when those areas get glued. Did I mention one of my jobs at my Dad's factory was sandblasting fertilizer mixers to prepare them for corrosion resistant paint?


I'm using Aleen's Tacky Glue, but you could use anything designed to bond paper permanently, as long as you let it dry as long as necessary for your type of glue. (Notice how I put that in bold italics?)

Before gluing, dampen a paper towel and have it ready to use it conscientiously to clean your fingers (you'll see in a minute) and any migrations of glue to the table or other non-glued surface.

Squeeze out a series of rows of glue back and forth on the unprinted side of Front -1 about a half inch (12mm) apart.

Spread the glue with your finger so that it covers the entire surface.  Your goal is to have a continuous thin film of glue.  Clean your finger with the damp towel.


Place Front-1 on the card where you had planned and prepared, and squeegee it down with something stiff but flexible like a credit card or a student ID


Spread the glue on Front-2 and place it up against Front-1 so the A and B are aligned, and then continue to cut and glue the remaining parts to the card stock.

The Light Trap Base and the Light Trap Cover are 15 inches (380mm) long.  If your box isn't big enough you could tape two pieces together and glue the template to that.  It might make a bit of a weak point while you're working on it, but it won't make any difference once everything is glued together.


By the time you've glued all the parts down to the card stock, the first one has probably dried enough to cut them all out right to the template edges with scissors.


At this point it is necessary to let the glue dry.  Wet paper is pretty touchy and easily torn when trying to cut with a blade or score it.

Once it is dry, cut out the pinhole openings on the Front. This requires a craft knife and may need to be done with the supervision of an adult.  Generally it's a good idea to use a steel rule, but I've found that, with a sharp knife, it's easier and more accurate to cut these short segments free hand.  Be particularly careful not to cut the narrow gap between the openings. This could be done with hollow point punch if you had one of those.


Score all the folded lines with a straight edge and a ball point pen so they fold accurately and cleanly.


Fold all the scored lines and give them a good crease.


The Front folds so the flaps are on the inside of the camera. Apply glue to the light grey side panel on one side and glue it to the flaps.  Make sure the flaps come together without overlapping and the corners are square.  Clamp the top together with binder clips. Lay that side on the table and with your finger, squeegee the parts together so they adhere along their whole length.


Repeat for the other side.

Apply glue to the Side Stiffener/Ridge pieces and glue them inside the camera.  Note how they go up against the bottom of the camera and the sides with the pinholes leaving a slight gap toward the back.


Clamp the box together by placing rubber bands around the box and let it dry. If any glue has squeezed out, use the damp paper towel to clean it off.


Now cut out the pinhole openings on the Brace/Pinhole Mount, and then score and fold it.

Score and fold the Back. Note the flaps go on the outside.



The Front won't be completely dry but you should be able to continue.

The Back is glued together around the Front for a custom fit.  In my film cameras, there is internal structure to keep the Front from getting crushed while you do this but this camera has none. This is one of the functions of the Brace/Pinhole Mount.  With the side with holes for the pinhole facing up, place the Brace/Pinhole Mount into the camera.  It should fit slightly loosely.


Stray glue could accidentally make the Back permanently attached to the Front, so wrap the open end of the Front with a bit of waxed paper.


Spread glue on the flaps, and form the Back around the front of the camera.  Note that the flaps won't come completely together in the center. Try to get them set as square as possible. With your damp paper towel, clean off any glue that squeezes out and clamp with rubber bands.


Score and fold the flaps on the Light Trap Base and glue and clamp it.


Fold, glue and clamp the Pinhole Mount Lock

Wait for everything to dry.

When it is dry, remove the rubber bands and before removing the Back, make a mark on the side with the pinholes so you can match up your custom fit when you close the camera after loading it in the dark room.  When you remove the Back, there may be some bits of wax paper that stuck that you will have to pick off,


Put the Back on and draw a line around the Front at the the end of the Back for reference when it's removed.

Wrap the Light Trap Base around the camera pushed right up against the closed Back so that it forms tightly around the Front.  Then apply glue to the inside of the Light Trap Base, put it in place around the Front up against the closed Back and clamp it with a rubber band. Being careful not to move the Light Trap Base, remove the Back.  Clean off any glue that squeezed out. Check to make sure the Light Trap Base is still up against that reference line.

Wait a few minutes until the glue dries enough that the Light Trap Base stays in place.  Replace the Back. Roll off the rubber band and wrap the Light Trap Cover around the Light Trap Base and Back so it forms around the corners and fits tightly. If it's slightly too long and overlaps, cut it so the to ends come together. 

Remove the Back again and apply glue to the top of the Light Trap Base trying to leave a little gap on the side toward the Back.


Replace the Back again and glue the Light Trap Cover around the Light Trap Base overlapping the Back.  Clamp it in place with the rubber band.  Draw another reference line around the Back where the Light Trap Cover comes to, and remove the Back so it doesn't get glued in place.


Remove the Brace/Pinhole Mount. Run your finger and thumb around the Light Trap to make sure it's adhered all the way around.  


Blacken the space on the Back where it slides under the Light Trap so you'll be able to tell that it's closed under safelight.


At this point, unless you're absolutely sure it's opaque from previous experimentation, you should put a couple coats of matte black paint on the inside.  I usually use fast drying spray paint like Krylon, but it's smelly and messy.  I'm looking into other options like black interior latex or india ink which my wife tells me will work, but once you get it on something it never comes out.

Now that we no longer need the Brace/Pinhole Mount as a brace, cut away the grey shaded parts of the Pinhole Mount.


Being careful not to disturb the drying Light Trap, place the Pinhole Mount in place with the pinhole openings on the Mount lined up with openings on the camera Front. Apply glue to the the Pinhole Mount Lock, and place it inside the camera so that it pushes the Pinhole Mount firmly against the bottom.  Clamp it in place and remove the Pinhole Mount. Press it down with your fingers so it's entire area is adhered.



Wait for everything to dry while you drill and mount the pinholes.

The pinholes are drilled with #10 quilting needles which have a diameter just shy of half a millimeter.  I find the easiest way to drill with them is to insert them into the eraser of a pencil. Try to make it as aligned with the pencil as possible.

The thin metal is either .002 in (.051mm) Brass Shim Stock (the iconic material from the days when engine valves were shimmed but it's still available) or the aluminum from beverage cans. You could use disposable pie pans in a pinch.

Place your brass or aluminum on something with a bit of thickness that the needle will pierce easily, like several layers of corrugated cardboard, foam core or styrofoam. Steadying the needle with your thumb and forefinger, rotate the pencil and slowly drill down.  You might not even feel it when it goes through. Push the needle through to it's full diameter. Be careful not to bend the metal when you pull the needle out.


There will be a burr uplifted on the other side.


Sand off the burr using a bit of the finest abrasive you can find until it feels smooth to the touch (at least 200 grit).  You can usually find finer grades in the Automotive section of the hardware store.

Stick the needle back in the hole and give it a couple spins to remove any dust from the sanding.

See how easy it is?

Here's the six that I'm putting on this camera , again made in under ten minutes. 


The middle two don't look exactly round, but they have a pretty smooth edge.  I'm going to randomly mount them all and we'll see if we can tell which are the two odd ones from the pictures they make.

Tape them onto the Pinhole Mount so they'll be positioned between the Mount and the Front. Since they'll be hidden by the Mount, it doesn't matter that the tape isn't black.


Make sure you place the pinhole roughly in the middle of the opening. Check that you don't cover any of them with tape.


Then replace the Pinhole Mount in the camera, and snap it under the Pinhole Mount Lock.

Each aperture needs a separate shutter made with opaque black tape, with one end folded over on itself to make a handle.  I often see electrical tape suggested for this.  It is inexpensive and readily available, but I have seen some electrical tape that won't stick at all to cardboard and some that does, so check before the workshop. The ideal material is opaque black photographic tape, which is available from art supply and photographic products dealers.  Black vinyl repair and decorating tape is good, but I don't find it in many hardware stores. Black gaffers or duct tape is hard to tear into little pieces and sticks a little too well for this application.  Regular black masking tape might work if you used about three layers for each shutter. 


Make sure the shutters don't overlap so you don't pull off two instead of just the one you want to make the exposure with.

Whatever tape you choose make sure to have a supply handy as they have a tendency to get lost, and encourage participants to carry of few spares in their pocket stuck on a piece of card stock.  If you lose one, hold a finger over the pinhole until you get back to the darkroom.

Make some kind of a mark on the sides of the camera surrounding each set of pinholes at the location of the pinholes that will be used for viewfinding.

And now you're ready to take pictures.  I'll do another post in a few days on loading and viewfinding.

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