Cyanotype Camera Obscura




Introduction: Cyanotype Camera Obscura

Cyanotypes are prints made with light striking ferric ammonium citrate - potassium ferricyanide empregnated paper. The ferric ammonium citrate is the light sensitive compound. The prints are negatives, dark things are white and others are various shades of blue. The technique dates to 1842 with Sir John Herschel using it to make inexpensive copies of astronomical calculations. In 1843, Ms Anna Adkins made booklets of British Algae and hers is recognized as the first picture book in history.

The literature, “Cyanotype” from Sarah Van Keuren’s book “A Non-Silver Manual: Cyanotype, Vandyke Brown, Palladium & Gum Bichromate with instructions for making light-resists including pinhole photography”, was used for the exposures and basic camera design. The prints were developed and rinsed with water as the manufacturer of the Sunprint paper instructed.

Most of the materials needed are in Photo 1. The shoebox, duct tape, wood glue and cardboard are for fitting the lens into the box. The paint is matte Black. The Solar Print paper was for $7:00 at a local toy store. Not shown, but used, were cheap wooden chop sticks used for furring strips and shimming - Popsicle sticks could also be used.

The lens is an old, school projector lens I got for free as our old school converted to digital projection. The lens has written on it: "Ektanar C 102 - 152 mm f 3.5 zoom projection". The focal point was 5.5 cm from the rear of the lens and could be varied by twisting the zoom.

Step 1: Box Made

First, all of the holes in the shoe box had to be covered. Then the lens hole was cut out and.the lens fitted and seated using cardboard strips. Glue was placed in the cardboard "bed".

5.5 cm from the rear of the lens a cardboard wall was placed and held with glue and furring strips as seen in the photos.

Step 2: Sunprint Paper Holder

In this photo you may see the wooden strips making a Sunprint Paper holder. The print paper will be held by these strips while the exposure is taking place. The paper is free between these holders. I think this may have added to undulated focus in the prints. This will be better done in version 2.0 of the cyanotype camera in that perhaps I will use a plastic sheath for the print paper to hold it on more securely.

Step 3: The Completed Cyanocamera With Address Label

With the lens bed and the focal point securely glued into place, flat black matte paint was sprayed both inside and outside.

The lens was fitted into the box, light leakage was checked and covered. With exposures of 40 minutes or so, I placed an address label on the box so I could take it somewhere and leave it for an exposure. Even out here where I live, people may see a box and think it is some sort of explosive device. I hoped that the address label would make someone telephone me before calling in the Sheriff.

Step 4: Fields and Trees(1) and Dirt Road (2)

The cyanocamera was loaded with Sunprint paper and exposed for 40 minutes to a field scene for (1) on an overcast day. Development was with rinsing water according to the manufacturer's procedure. The round, upper right object was a heavy flashlight I used to weigh down the lid of the box because of construction that might jar it.

The dirt road(2) was exposed for 45 minutes, but with more Sun and no flashlight. I was curious because of the deep blue road which appears black in the cell phone picture.

The literature indicated that the blue paper would turn mostly white during the exposure. I noticed that there was lot of blue left on the sunprint paper after the exposure.

Step 5: Positive Prints

The developed Cyanoprint was photographed with a cell phone for permanency as the blue and white began to mull rather quickly. Within about 45 minutes after the rinsing, the mulling was so great that significant detail was lost.

Shown is a positive print of the blue Sunprint Negative using Smart Photo Editor for the conversion.

This i'ble was a lot of fun! Very special for photographers and artists interested in alternative processes!

1 Person Made This Project!


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8 Discussions


11 months ago

I’m a teacher in Ontario (Canada) and I teach a high school photography class (AWQ3M) which is an 11th grade credit. To learn the fundamentals of how a camera
functions and to experiment with exotic photographic processes, I assigned a
project inspired by this instructable. The students were tasked with building
their own cyanotype camera to take photographs with. Armed with a slew of old
lenses, magnifying glasses, semi-opaque mylar, a ruler, and common craft
materials, the students first had to choose a lens and accurately find its
focal length. If this is something you know nothing about, here is a succinct
video that explains how to calculate the focal length of a lens.

Next they were tasked with designing an enclosure (body of the camera) using Tinkercad. This enabled them to easily work out their design concepts in 3D. They then started to build
rapid cardboard prototypes as proof of concepts and started to refine their
designs. The criteria for the camera was to be able to: preview the shot, adjust
the focus, reliably hold a piece of cyanotype paper in the right position, and
be mounted onto a standard tripod, using the material/process of their choice.

Each student tackled the assignment differently. Some chose to create bellows to adjust the focus of their camera, while others used cardboard tubes that nested into each other to
achieve the same effect. Some chose to use only cardboard and cardstock to
construct their cameras, others opted to 3D print their designs, and one student
even made their own roll of cyanotype paper paired with an advancement
mechanism for being able to take up to 10 shots before having to develop the

The students gained hands on knowledge about optics, as well as the importance of making the interior of the camera body completely light proof and free of reflective
material. They learned about exposure times, the sun as a variable, and
different development methods to improve their prints, experimenting with
different chemical additives to the water. *Pro Tip: Adding Hydrogen Peroxide
(3%) to the developer bath (which is just water) speeds up the development
process significantly, making it possible to achieve that deep blue hue almost

An important safety note, if you decide to make this project with your students, be sure to stress the importance of always verifying that the lens is never pointed directly at
the sun, as it has the potential of starting a fire!

For tripod mounting, some students simply glued ¼-20 nuts to the undersides of their cameras, while others took advantage of our 3D printer and printed quick release plates for
their cameras. Quite a few students developed simple carriers for the cyanotype
paper to facilitate the process of inserting and removing the cyanotype paper. Some
even made multiple cameras as the exposure times lasted the entire period,
setting up multiple cameras enabled them to get more bang for their buck during
a single 75-minute period. If others are thinking about doing a similar project,
I suggest encouraging the students to make multiple cameras of varying designs
to speed up the experimentation process and to increase their odds of achieving
positive results. Something else I suggest is inviting the students to place
their cameras sometime before class, that way they gain longer exposure times.

The final step includes an entire postproduction process which is required to turn the negative cyanotypes into positive images. There are plenty of decisions to be made when
tweaking the positives as well and many other photographic alteration techniques
come into play. They are then faced with how best to print their final images
for presentation. Some chose to house their final images within their cameras,
others chose to frame them with large mattes around them in order to emphasize
the preciousness of their images, and some even printed large scale formats of
small subjects to toy with the concept of scale and perception.

Things to avoid:

Pinhole-type Cameras:
We discovered that they don’t let in enough UV
light to affect the cyanotype paper and barely produce an image, if any, even
after hours of exposure time.

Low Contrast Subjects: Subjects with little to no contrast, such as bushes
in front of coniferous trees, do not produce good images. A single subject,
isolated by a starkly different and simple background, seems to produce the
best images.

Short Exposure Times: Exposures less than 45 minutes, produce only the
faintest of images if any at all.


Reply 11 months ago

This is awesome! Thanks for sharing your resources and references!


Reply 11 months ago

Thanks audreyobscura! I love the new Teacher's Notes platform! Such a great initiative!
Mr. Ham


1 year ago

Try developing the paper in vinegar. You'll be amazed at the result.


2 years ago

Curious if anyone else has further results. I'll post results here too if I can find a nice lens and then anything comes of it :)


4 years ago

Woah! I am trying to make one of these right now! Found your project when I searched for 'camera obscura' on the site. I just made my first exposure at 20 minutes at f1.8 in full sun and it DID NOT work :( gonna try again for a 40 minute exposure tomorrow morning. Great minds, right?!


Reply 4 years ago

Thank you Audreyobscura,

It is hit or miss! My camera has a huge lens for gathering light so it may be less of an exposure that others. We are finding that variables are lens size, Sun, even the paper(including the manufacturer). Good luck and stay posted!