Van Dyke Photography

Produced by ChristopherMorrow

CHEM- 319

General Information

• The chemical reaction that takes place in order for the van dyke photography to work is called a redox reaction (oxidation-reduction reaction).
• An oxidation-reduction reaction is a chemical reaction where the oxidation number of two atoms or ions change; one from the gain of one or more electrons and one from the loss of one or more electrons. The following reaction occurs on exposure of a treated surface to sunlight.

• To finalize the image on the canvas the sodium thiosulfate reacts with remaining silver (I) salts which forms a compound that is easily washed away.

Hazards

• When doing this lab procedure be sure to wear gloves because the prussian blue and aqueous silver (I) nitrate will stain your hands.
• Wear goggles always when in the lab because some of the chemicals you are working with like silver (I) nitrate can burn your skin and even cause blindness."YOU ONLY HAVE ONE PAIR OF EYES" -Dr. Mabrouk-
• If any of the chemicals come into contact with your skin or eyes immediately flush with water for several minutes. Contact your professor if the burning continues.

Procedure

• Find an area with very little light
• Take two different types of canvas fabric that you wish to have the print on and apply the sensitizer.
• When applying the sensitizer make sure you use a foam paintbrush and use vertical and horizontal strokes.
• Since there is little light it is hard to see so make sure you don't leave any spots untreated with the sensitizer.
• Have a piece of foam board to lay your canvas on.
• Let dry for two minutes then dry using a hairdryer on low setting until completely dry. If it is not properly dried then the image will not turn out clear.
• With the treated side facing up place your transparency or flat object on the canvas. Then place a piece of glass on top.
• To make sure the glass does not move secure with four binder clamps in each corner.
• Once the clamps are in place you are ready to place the set-up in the sun. Before walking outside take proper precaution and put on sunglasses since you have been in a dark room for the past hour and your eyes are not adjusted.
• Leave the set up in the sun for 2-6 minutes, depending on the sun's intensity.
• Take back inside and disassemble the set-up.
• Take the canvas and place in a bath of running water for at least 2 minutes to remove impurites such as iron salts and unexposed silver (I) nitrate. After the water bath the canvas should appear yellow. This also is the part that develops the picture on your canvas.
• Place the canvas in 3% sodium thiosulfate for less than a minute. After this immersion the canvas should have turned brown.
• Next place the canvas in 1% sodium sulfite for 1-2 minutes. This will remove any extra sodium thiosulfate from the previous step.
• Rinse under running water for the next 10 minutes
• Place on a foam board and let dry.

Observations

The one thing that I observed that really stuck out and can help others is applying the sensitizer. When you are applying the sensitizer you really need to be careful not to have splotches. You really need to concentrate on applying an even coat. When I did my first one I didn't even have sensitizer in this big spot in the middle and when I tried to fill it in later it never matched the original color. So be careful when applying the sensitizer if you wish to have an even color throughout the canvas.

Reflections

The Van-Dyke photography was one of my favorite labs this year. There is so much room for creativity because you can put anything you want on the canvas. We all showed our creativity using different objects and transparencies with pictures on them. I would recommend anyone who reads this to take this class. It is very interesting and makes you look at art in a whole new light. Everyone should also follow the steps above and try this experiment on their own.