In-Camera Cyanotype using the Two-bath Cyanotype

In this experiment Bernd Hutschenreuther explores the two-bath separate solutions process for cyanotype, similar to Sir John Herschel’s first method. A cyanotype image was created using a 6×9 cm folding camera with an extended exposure time due to weak winter sunlight.

Writer and photography / Bernd Hutschenreuther

Several attempts to make cyanotypes directly in the camera have been made and published here, both successful, unsuccessful and a negative print cyanotype. This is how this attempt was made:

Preparation:

Camera and Exposure: A 6×9 cm folding camera with a 3.5/105 Bonotar lens was used. The paper was exposed for 4 to 6 hours between 10 a.m. and 4 p.m. under weak winter sunlight.

The Belfocca camera on the balcony — A 6×9 cm folding camera with a 3.5/105 Bonotar lens was used.

The Belfocca camera with open back — The paper was exposed for 4 to 6 hours between 10 a.m. and 4 p.m. under weak winter sunlight.

Method: The process followed the early cyanotype technique developed by Herschel, using a separate two-bath cyanotype solution for sensitization and development.

At the balcony. 4 hour exposure — At the balcony. 4-hour exposure.

At the balcony. 4 hour exposure with the contrast improved. — At the balcony. 4-hour exposure with the contrast improved. When I scanned the picture it autoadjusted contrast.

At the balcony. 4 hour exposure inverted to show the positive. — At the balcony. 4-hour exposure inverted to show the positive. I used Photoshop to make the positive.

Coating:

The paper was coated with a light-sensitive iron(III) citrate (ferric citrate) solution and dried. It appeared very light yellow and remained light-sensitive for several days.

Exposure:

The coated paper was placed inside the camera and exposed with the lens open in natural sunlight. After exposure, the paper changed to a light yellowish-brown hue.

Development:

After exposure, a potassium ferricyanide (red blood lye salt) solution was applied using a brush. The image immediately developed into blue tones. I used a brush to brush the development solution over the picture. This way, only a very small amount of the solution was necessary.

Fixing:

The paper was rinsed with water to remove excess chemicals and fix the image.

A 6 hour in-camera exposure. — A 6-hour in-camera exposure.

A 6 hour in-camera exposure inverted to show the positive. — A 6-hour in-camera exposure, inverted to show the positive. I used Photoshop to make the positive.

Post-Processing:

The developed image was scanned, displaying a light blue tone.

To enhance visibility, contrast was adjusted, and the image was inverted, producing detailed results quickly.

“In Dresden, we had only some days with sun. In cloudy whether I have the same experience as Herschel during the first years. I think the result will be better with enough hours of light.”

Further observations:

Using the original mixed-solution cyanotype process would have caused the image to wash away during fixing, highlighting the advantage of the separate solutions method.
I observed improvements in the in-camera cyanotype process. The paper becomes more light-sensitive when the pH of the citrate solution is between 3 and 4, making it slightly acidic. A small amount of citric acid can be added to achieve this, though I have not tested it yet. I experimented with variations, but changing weather conditions and insufficient sunlight affected the process. Fortunately, my initial attempts were successful.

The 6-hour exposure inverted. I used Photoshop to make the positive.

Bernd Hutschenreuther, born in East Germany, has been using pinhole cameras, cyanotypes, developing with caffenol and most recently lumen prints. See Bernd’s gallery.