Monday, January 1, 2018

Building the Pinhole Lab Camera

June 2019. When my university retiree account disappeared with a new change in policy, the pictures I uploaded to this blog while logged into that account disappeared. I'm working on fixing that but it's going to be at least a summer long project. 

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.

Friday, December 15, 2017

A Pinhole Lab Camera

June 2019. When my university retiree account disappeared with a new change in policy, the pictures I uploaded to this blog while logged into that account disappeared. I'm working on fixing that but it's going to be at least a summer long project. 

Preface

I have this fantasy of a pinhole class.  It could be a five day camp or a regular school class for several weeks. I think it would have to be at least junior high school, but it could be with senior citizens.  I'm really done with half day workshops. For those I always seem to end up spending all my time identifying light leaks and fixing them and it ends up just being a technical demonstration and nobody gets to play with pinhole photography.

I started getting really serious about pinhole when I worked with the university's science outreach department to create a program using pinhole photography as an example of physics and chemistry concepts.  I'd still like to include that sort of thing and I can imagine it being a supplement to a variety of science, art or general liberal studies classes, but I'd like it to concentrate on iconic experiences in pinhole photography, although a lot of this is going to inform one's practice of lensed photography.

Building your own camera from raw materials is one of the iconic experiences of pinhole photography,  I had a tenured History prof tell me last year that building a pinhole camera in Junior High School was one of the most memorable experiences of his education.

Links:    Construction    Feeding and Use    Link to Templates   Excusado  Reducer and extender

A New Camera
If I ever got the chance to do this extended curriculum, I've been developing the camera I think I'd use. (n.b. the cameras in the picture above are prototypes with minor variations)

In previous workshops I used a camera design I was given by Ruth Thorne-Thomsen.  It was pretty quick and easy to build and load. I had fourth graders successfully do it without much trouble. It was slightly prone to light leaks, but in predictable places and usually easy to fix with tape. One fifth grader who had been in a workshop as a fourth grader the year before remembered that most problems could be fixed with more tape. It could be built with several distances from pinhole to paper, but it was less confusing if they all made identical cameras and although I used to bring examples of shorter and longer cameras and let the kids use them, everyone didn't get to experiment. The design's biggest weakness is the dependence on a supply of black opaque photographic tape, which is a little expensive and has to be ordered from a photo or art supply house.

I also had kids build curved cameras out of La Choy Noodle cans because that non-flat film plane is so critical a concept in pinhole photography, but those plastic lids are irritatingly hard to make light tight.

For this new camera, I'm sticking with a one-shot camera loaded with photographic paper, for the budgetary aspects and for learning objectives. Timely feedback is a critical factor in learning, especially if it's matched to a protocol where you try to predict (or imagine) how something will work out. Having to go back to the darkroom gives the student just enough time to wonder about that sort of thing but it's short enough to remember what they did before finding out if it worked.

It's the same printed-template-glued-to-cardboard-and-folded-and-glued-together concept as most of my other cameras.

The new camera has multiple formats that would allow each participant to experiment with several parameters:
  • pinhole to film distance (what would be focal length on a lens), 
  • aspect ratio and film size, 
  • adjusting the field of view by changing where the pinhole is in relation to the center of the film plane (rising and falling front) and 
  • curvature of the film plane.  
It's also set up so the size of the pinhole could be changed easily.

Formats:

It's designed around a format of 2½ x 4 inches (64 x 102mm).

The basic concept is that's an even division of an 8 x 10 inch (20.3 x 25.4cm) sheet of paper - one eighth.

In almost every school environment budget is going to be an issue.

That may seem a little small, but it's bigger than 6x9cm on 120 film or Instax prints.

It's aspect ratio - 5:8 - is just a hair wider than 35mm's 2:3 and it's pretty close to the 9:16 screen most people spend a lot of time looking at on laptops and HDTV.

An advantage for my lab camera is the ratio is great enough that the dimensions of a box to accommodate that shape, if you put a pinhole on two sides, can have two distinctly different pinhole to film distances with all the f-ratio, angle of view, vignetting and perspective of depth principles that implies.

The box is approx. 4 x 4 x 2½ inches. That allows 4 inches to the pinhole on the rectangular end (34.5 x 52 degrees - about a 35mm 35mm equivalent), and 2.5 inches with the pinhole on the square side. (53.5 x 77 degrees, about a 23mm 35mm equivalent).

For the 2½ inch pinhole distance, I put the pinhole and the paper toward the end opposite the opening so it would be easy to load accurately in the darkroom.





For the 4 inch distance the paper would go in the removable cover. I can hear you thinking how that is just an invitation to a light leak. The body includes a light trap the cover fits into, which I'll detail later on.




Of course by turning the camera on it's side you also have vertical options.


Since you've got a four inch square available on the short side of the camera, if you put an extra pinhole right in the middle of that side, you've got a 4 x 4 inch square format.





I know I've just blown the even divisions of an 8 x 10 sheet of paper, but if you're going to make contact prints (an iconic pinhole experience) you'll need lots of test strips, and who says you can't just put a 2 inch negative in if you want to. (What would that do to the angle of view?)

Curved film planes and panoramic formats are other critical concepts in pinhole photography.

If you put a little ridge on the side of the camera a half inch from the front, a 2½ x 6 inch piece of paper held between the camera back and those ridges forms very close to a 2½ inch radius curve.




You could also do this with a 4 x 6 inch piece of paper.

Now,  make sure your half inch ridge is only 2½ inches high and put another ridge across the 2½ inch side, 1½ inches down the back. If you place a 2½ x 6 inch piece of paper between those ridges and the camera back,  you've got kind of an odd curve varying from about 2¼ to 4 inches. That's definitely not the perfect radius which is kind of expected of a curved film plane camera.  And the pinhole says: "I don't care, it doesn't matter how far from the film plane I am, it just changes the exposure."



This would be kind of interesting math to see if the increasingly reduced area of the foreshortened ellipse of the pinhole as you view from the side would compensate for the technically faster f-ratio at the sides.

Even with this elongated format, you can turn it to vertical.


Rising and falling front.

The entire image cast by the pinhole and how the image appears when cropped to different parts of that circle is a concept easily explored in pinhole photography. If you have view camera experience, I'm speaking here of rising and falling fronts.

Just quickly, if the pinhole is above the center of the film plane, it will somewhat appear that the camera is getting a higher point of view.  Since pinhole is all about straight lines it's easy to demonstrate that you're looking in a different direction.  Since no focusing is going on it doesn't matter that this might be in a different plane. The pinhole doesn't care. Again, exposure will vary across the image, and you may see some vignetting, but those are easily managed variabilities that can be handled in making the positive. Probably the most common use of this function is to photograph a tall building without tilting the camera back so it doesn't look like it's falling over backward. If the camera is level, the apparently higher angle of view will still have parallel verticals. Another place you'd like to use this is landscapes with those curved film planes where you want to keep the horizon level so the distortion of the curved film plane isn't so distracting.  You can change where that horizon is in the composition with a rising or falling front. (Are you thinking Rule of Thirds?)

If you make another pinhole above the one in the middle, that's just like a rising front. If you've got the rising front extra pinhole, if you turn the camera over, it's a falling front. By the way, the axial pinhole of the 4 inch square is the rising/falling pinhole of the 2½ x 4 inch format, and vice versa.

Here are the three variations of the 2½ x 4 inch format at 2½ inches.

Rising front.


The on-axis pinhole.


And with the camera turned over, the falling front.


By taking a rising and falling front picture from the 4 x 4 inch and pasting them together you can get a 4 x 5½ inch format.


And of course you can do it with verticals, and the curved film planes, or shift to the left and right rather than up and down.  There's over a hundred variations.

Each one of these apertures would have a separate piece of tape as a shutter (which is another iconic pinhole experience).

Six Pinholes?

If we do this for both distances to the pinhole for both vertical and horizontal, that makes six pinholes. I can just hear you thinking: "Wait a minute, Nick, you're going to have these kids drill six pinholes?"  I propose making .5mm pinholes by completely piercing thin metal to the diameter of a #10 quilting needle. My reason is that it's so easy. I have never encountered someone who couldn't make a nearly perfect .5mm pinhole.  I've only seen about three that required a second try (Drill - don't just push).  This includes kids as young as third grade.

Here are a .5mm Gilder electron microscope aperture and the six pinholes I made in under ten minutes that were used to make the pinhole images in this post.



I know that this is larger than the calculated optimum for both pinhole distances we're working with but it's the smallest sewing needle I can find. I think the ease of making them and the predictability of the aperture supersedes the need for the "sharpest" pinhole possible.  I don't think "as sharp as possible" should be an objective of a beginning pinhole class. This is a chance to explore the pinhole aesthetic.

I know about micro-drills and electron microscope apertures, but drilling a pinhole with a needle is probaby the most iconic pinhole experience.

These oversized pinholes also have the advantage of speed.  At 2½ inches it's f127 and the 4 inch option is f203.  With photographic paper, we're looking at sunny day exposures of between 15 and 30 seconds, and cloudy day exposures of 2 to 5 minutes. I've never had problems with people dealing with long exposures, but let's just say you can get more done with shorter exposures.

The camera design includes mounting the pinholes on a removable holder, so if you have students who can deal with the extra trouble of drilling and measuring smaller pinholes, or slits, or zone plates, it's easy to change them to experiment, and you don't have to change all six at once.

The sun is a vengeful benefactor

Most bad experiences in a pinhole workshop are caused by light leaks from the sun sneaking through the joint where you open the camera to load paper or film.

When I made the moderately telephoto camera in a plain brown wrapper, and I cut down the camera back to make it easier to open, it occured to me if I cut a strip off the part I removed and glued it to the front box right up against the closed back, and then glued a strip with an overhang over it that the camera back would slide under, I would have a pretty reliable light trap that was easy to open and close.  Cutting off part of a box after it's been glued together is a bit of a hassle, so I added a separate part to accomplish this.


Quandaries

It takes some time and careful work to make. This camera requires proper glueing to stay together, and that means you have to wait for a while between at least four steps.  With Aleens Fast Drying Tacky Glue, I made one in around three hours working nearly continuously, letting parts dry while I cut out and folded the next part.  With regular white school glue you'd want those drying periods to be several hours.  Aleens Fast Drying glue costs four times as much as school glue.

It takes a 12 inch square of cardboard for the largest part. Only the largest economy size of breakfast cereal when opened flat is big enough, and 24 and 30 packs of canned beverages work.  Poster board from art supply stores or Walgreens for that matter come in 22 x 28 sheets that would be more than adequate for a camera (Get black).

It can all be done with scissors except for cutting out the holes for the pinholes which have to be done with a craft knife. Craft knives are dangerous.  How young a kid can you trust with an Xacto knife? I have used hollow point punches to make these holes, but they take a pretty good whack with a mallet to cut the hole.  Paper and card stock don't tolerate drills very well.

Is it all too much?  Would students just be bewildered? Some might, but if they can figure out video games, none of this should be too hard, and it's all reinforced by hands-on/minds-on experience with the concepts.

I'm wondering how long it would be before they came up with this:



or this:


I think I've got the template worked out now, and I'm working on a post on building and using the camera.

I'd love to hear some feedback.