Photography on Blueprint Paper



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I recently came across a large stock of old blueprint paper at my work. Considering it's been about 5 years since the blueprint printer has been used at the firm, all the blueprint paper is just jammed under the table in giant light-proof bags.

Background

Blueprint paper first caught my interest when trying to develop ideas for Anything but Ethernet. I remembered having some sort of blue paper that was light sensative when i was a child. You were supposed to set it up in the sun with interesting objests lain on top of it. Afterwards you'd run the paper under water and it would develop. Areas where the sinlight had hit the paper turned white, and dark areas turned blue, translucent objects placed on top only let a limited amount of light through, leading to a shade of blue. This is a well known art process known as . Of course when I was a kid thats all I tohught to do with it, but when I tohught of this light paper as some sort of basic interesting printer paper for anything but ethernet, I began researching it. Turns out its actually just cyanotype paper, and buying it in the 'Sun Print' packs is a major ripoff, at least compared to blueprint paper, which operates the same way (with the exception of developing).

A Little More About Blueprint Paper

Blueprint paper is a positive medium, not a negative one. Regular photographic paper is a negative medium. This is why you get 'negatives' when developing a roll of film, or a negative when developing a picture form an old film-plate camera (ex- a Brownie), or a pinhole camera. These initial images must then either be contact printed or enlarged to produce the positive. Either way youre developing film twice to get the final product. I know, this isnt a horrible inconveience, but it is a convenience when with blueprint paper, one simply has to expose the paper in the back of a camera, develop, and enjoy. The reason is that photographic paper, when developed, turns black where light has made contact, and stays white where light does not hit. The chemicals used in cyanotypes (blueprints) work inversely to those in standard photography. The chemicals in bluerprint paper, when developed, actually turn white where light has hit, and stay blue where no light has hit. Unexposed, undeveloped blueprint paper is yellow because of the chemical is it coated with. If no light ever hits this chemical, it turns dark blue when exposed to ammonia developer. However, when light hits the chemical, it breaks down, turning from yellow, to a pale blue. Since the chemical has been broken down by the light, it loses the characteristic of changing color when developed, thus staying white (or lighter blue).

Blueprint paper is also rather insensitive to light. It is meant to be exposed to a very large amount of light in a blueprint machine, and is really only meant to be used monochromatically. Blueprints are made by placing a transparency containing the drawing over a sheet of blueprint paper, and exposing it to very bright light.

Materials and Setup

Since today the company I work for uses plotters and AutoCAD, the blueprint printer and paper are rarely used or even acknowledged. Regardless, I was able to take home a few 2x3 foot sheets in a tube one day, and immediatly began expirimenting. I needed a safelight (like the red bulb in a photo darkroom), so I looked around. Blueprint paper is insensitive to yellow light, so a yellow bulb is the most logical choice for a safelight. Thanks to the blueprintphotography website, I realized that a 'no bug' bulb if a great choice. chances are you've seen these lights in the store. Simply a pastel yellow colored incandescant light bulb. I guess insects cant see yellow light so they arent attracted to, and dont fly to it as they do white lights. Blueprint paper is similar. It doesnt 'see' yellow light, and therefore no chemical change occurs in yellow light. The yellow 'party bulb' bulbs are also yellow, but are not as pure and uniform as the bug bulbs. It is a much wiser choice to simply buy the bug bulb, reather than a 'party bulb'.

Developing blueprints (for those who recall the blueprint machines) involves that lovely smelling chemical called ammonia. Ammonia is cheap, 28oz for $1, and can probably be found for cheaper at dollar stores. However, the hardware store can be your 'one stop shop' for blueprint imaging. Developing requires ammonia fumes, so what you need is a small cup to hold a bit of ammonia, and a larger container in which to hold the cup of ammonia as well as the prints. To start out, I used a Gladware container and the bottom portion of a water bottle. For small prints this works great.

Testing Paper

The first step was to actually make sure the blueprint paper was still good. If you are using new paper, this shouldnt be much of a problem, but when uising old paper stock, it's good to check. I turned on the safe light and opened the tube of paper, observing the fact that the top sheet (which had been the top sheet on the tablet back at the office for who knows how many years) was slightly less yellow than the other sheets. I proceeded to cut a sample piece from the top sheet and a sheet from the middle of my stack for testing. I didn't expose the sample pieces at all, and they went directly to the developer. As it turns out the slightly dicolored sheet on top still turned just as blue when developed as the middle sheet. Blueprint paper should be completly yellow to begin with, and will turn grey-blue when exposed to light. Another sample piece went on my windowsill to be completly exposed. I keep this small undeveloped sheet with my paper stock, so I know that when the stock poaper color resembles that of the exposed sheet, it has been exposed and therefore ruined. Developing a small undeveloped piece of your paper stock before going any further is a good idea. Your paper could be exposed, resulting in completly white pictures, and possibly leading you to believe that you are exposing the paper for too long in the camera. Save yourself the frustration and make sure your paper is good to begin with.

Contact Sheets

Next I had to prove that images could be transferred to the blueprint paper. The simplest way to transfer an image to a photo sensitive paper is by contact sheet. For this method you need an original and an undeveloped sheet of photo paper. Simply place the original on the photo paper and expose to light. This relies on a method similar to the 'sun prints.' A picture is simply lights and darks which can be transferred very easily. The first contact sheet came out well, and I was very pleased ot find out that the idea was working.

Blueprint Camera

Next was the most interesting step. I wanted to actually find or build a camera which could use blueprint paper as film. This isn't incredibly easy bedause unlike photographic paper, blueprint paper is not near as sensitive to light. If you've ever built a pinhole camera for use with standard photo paper, you know that it takes about 3 minutes to expose, depending on lighting. This is because the f-stop of a pinhole camera is incredibly tiny. It is, after all, a pinhole. Still, 3 minutes is not too long for the tiny amount of light entering the camera to expose the film properly. Blueprint paper would require many hours of bright light to work with a pinhole camera. More hours than are available in a single day, or even in a week's, or month's worth of fully sunny days. Blueprint paper is simply not as sensative. As I stated above, blueprint paper is less sensitive to light because of it's intended use. It turns completly white easily when exposed to the intense light inside a blueprint machine, but natural light, and other artifical lights take longer, and light coming through a lens is even dimmer, resulting in an even longer exposure time. Relying on a pinhole to focus the light allows just the tiniest amount of light to come through, and blueprint paper takes a long time to be affected by this very faint light, resulting in an unimaginable exposure time.

So pinhole cameras are out. But simply because we can't use a pinhole camera doesnt mean we cant still make a camera of our own. Obviously, the way to let in more light is to have a bigger f-stop. This basically means a bigger hole (though f-stop is technically the focal length of the lens divided by it's diameter).

Finding the Right Camera: Lenses & F-stops

A pinhole camera's f-stop varies, but is amost always in the hundreds (ie: f/200 or greater). An old box camera (ex- Brownie) could be used, and will typically offer something like f/8. At f/8, you're looking at about a 4 hour exposure time. 35mm cameras often offer various f-stops from f/1.4 to f/22, These stops allow for photographic film to expose in a split-second, but the smaller f-stops (higher numbers) would still constrict light a bit too much for a timely blueprint photograph. F/1.4 through f/4 are appropriate for a sub-one-hour exposure time with blueprint paper in full sunlight, but a 35mm camera is a bad choice for blueprint photography. Why? Because blueprints are a positive medium! Exposing blueprint paper in a 35mm would produce a 35mm pictue!

Looks like this one is going to be custom built.

OK, so why not a lens off a 35mm in a home built box? Well, the focal length is too short. Remmber that the distance from lens to film in a 35mm isnt that long. To get the image in focus youd have to move the paper so close to the lens that youd just get a 35mm image, and then a home built camera is pointless. I needed a different lens. A long focal length and a large diameter. I managed to find a lens from an old Kodak slide projector. Not exactly the most ideal lens for photography, but good in this case because of it's acceptable f-stop and focal length. A focal length of 5 inches and f-stop of f/3.5 means a ~1.4" diameter. Signifigantly larger than a pinhole, and with a focal length long enough to produce an acceptable image size.

Finding the Right Camera: Camera Box

Now that I had an appropriate lens, I needed a good box. Remembering my pinhole camera, I wanted to find something easily light-sealable. I settled on a small box about 3.75" square and 3" tall, and walls 1/16" thick, with an attached lid. My lens has a housing which extends about 2" beyond the lens, so I figured this would give me a max distance from lens to film of 5.75". The optimum distance, 5" could be easily achieved to focus an image on the back of the box. So I cut the large hole required to hold the lens in place. The holve was cut just slightly smaller than the lens itself, so that friction could hold it it, then it could be taped to prevent further unwanted light to enter around the edges.


Here is a good picture of the camera with the window framed up
for the shot seen below. As you can see, the wide lens allows
a lot of light to make it to the film. The image is clearly
visible even with the room filled by daylight.

Field of View & Focus

A major disadvantage to this design is the fact that (as any photographer knows) a large f-stop means a smaller field of view! In other words, with a large f-stop, you have a very sensitive focus. With a small f-stop, objects in the foreground and in the background can both be in focus, however, when the f-stop is enlarged, focus on objects becomes more important. Since focal length of a lens is constant, this simply means that the hole letting in light is changing size. With the large diameter of the lens in use here, it is very particular about the distance of your object form the lens. This means that moving the lens back and forth to focus would be even more important. Since I intended to take landscape photos at first, I focused the camera for 15 ft and taped the lens in place.

Focusing the camera is relatively easy. just turn all light sin a room dark, and turn on one bulb. Step back with your camera to the distance from which you want to focus. Open up your camera lid, point the lens at teh light bulb, and look at the projected image on the back wall of the camera. Move the lens back and forthe till it's focused on the back wall, and you're done.

First Photos

I cut a strip off a sheet of blueprint paper, and sliced it into little film pieces, 3 by 3.75 inches. Taped one in the back of my camera, and composed my first shot. I simply set the camera in the back of my room, pointed at my desk form about 10 ft back. I turned on all my lights, since I figured I'd need as much as I can get. In all I had four 4 foot cool flourescent lights, two 4 foot flourescent UV (black) lights, a cool compact flourescent, a 17 inch warm flourescent and a 17 inch UV flourescent, as well as a blue painted bulb (party bulb!), which was the center point of the shot. I didnt turn on the yellow bug bulb, because even tohugh it is fairly bright at 100 watts, the yellow light would have had no effect on the photograph. As well, the UV (black) lights were not necessary, because as I would find out later, blueprint paper is insensitive to this light too.

I let the shot expose for 30 minutes, turned outall my lights, turned the bug light on, and took out the film. Developed it, and saw only a line and a dot appear. I figured out that the line and dot were from the 17 inch floursecent desk lamp, and the adjacent compact flourescent bulb. Clearly 30 minutes was too short to expose a picture of any detail.



Also note how blurry these lights are, which were only about 8 ft from the camera.

I realized that light leaks werent going to bne a huge problem. Where as with a regular pinhole camera one must be careful of light leaks, blueprint paper isnt as sensative, and asnt about to fall prey to tiny leaks. Besides, it was clear form this image that if light leaks did matter, my camera didnt have any.

I concluded that even with ample lighting, indoor shots were going to be hard. For my second shot, I waited until morning. I prepared the camera before school and placed a piece of duct tape over the lens as a cap. When I got to school, I set the camera in the back window of my car, and let it expose for a total of about 3 hours and 40 minutes. For the first half of the shot, it was mostly sunny, but had changed to overcast after about 2 hours. I wasn't too worried tohugh, because of the snow. This, I figured, would make for ample brightness even in the absence of fulll sunlight. I got home and developed the film to find that it had overexposed this time.



You can see how the image very faintly comes in in the corners, because the lights is far less intense here.

So, 30 minutes indoor: Much too short
260 minutes outdoor: Far too long.

I composed the third shot quickly, facing out the back window. Same conditions as before, overcast, but plenty bright because of the snow cover. This shot exposed for one hour. I developed it and to my surprise it actually came out.



It is a bit light, and I figured I could afford to go with even less time with the current light conditions.



Exposed this shot out my front window for 45 minutes, and it still turned out a bit light.

The next day was completly clear. I took advantage of the full sunlight and composed a shot out my back window again. I exposed the shot for one hour, though with full sunlight, it overexposed.



As you can see, the same thing occurs as in the second shot, at the corners you can see a faint picture.

Next, I composed a shot out my front second story window, looking toward the setting sun. The idea was to capture a cool effect as the sun set. That is, a streak of light across the image. Unfortunately, given the results of the previous photo, I only let the initial shot for this scene expose for fifteen minutes. Not quite long enough to capture an arc.



Surprisingly, this picture came out alright. It was horribly blurry but at least it wasnt over or under exposed. I was afraid that the 15 minute time would simply be too short. However, it appeared to be too long.

The next two pictures were timed at 5 and 10 minutes, respectively. 5 minutes seemed to produce a slightly dark image, so I went for the mid point, 10 minutes on the final shot, which came out rather well.



The following two shots are taken looking through a window. The camera was placed about 8 ft from the window pane, so it is blurry, while the outside trees are in focus.



The first image was taken for 20 minutes, directly after the 3 shots of the sunset, so little natural light was still available. Beside that, I opened the camera to focus quickly with the film inside. This resulted in more washing out than I expected, you can see how the dark parts of this image are not very dark. Between the lack of light and the accidental exposure of the paper, It is a lousy image. I composed the same shot the next day, midday, with overcast skies. I exposed the film for 30 minutes and it came out pretty good. Though I intended for the window to be out of focus, and the trees in, it all ended up blurry because the trees were moving slightly back and forth with the wind. With an exposure time of half an hour, it's important for your subject to stay still!

Since I figured I had taken enough landscapes to test my camera, I decided to change it's focus. Since light leaks werent a big problem, the sealing tape around the lens wasnt really necessary. I removed the tape and it is now held in by friction alone. Unfortunately, I did not anticipate the necessary distance from lens to film for close up photos. With teh lens moved out as far as it will go, I can still only photograph objects at 3 ft.

This shot is the first 'closeup'. It exposed for 45 minutes, Indoor, With a lightbuld as the subject. Again, all the same lights were turned on to provide as much light as possible.



Again, for an indoor shot, 45 minutes was simply too short. You can see the bulb clearly enough, and partially the clip to which it is attached.