Cyanotype Demostration

There will be cyanotype demostrations during the Open House weekend - 28 & 29th July, 2018

What's On Notes - 28 & 29 July
openhousemelbourne.org - The Melbourne Camera Club
'Melbourne & Her People' Exhibition
A Short History
Traditional Darkroom Printmakers Group
Exhibitions
Cyanotype - Wikipedia

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Cyanotype aka  Photochemical blueprinting

One of the oldest and longest surviving photographic processes

The phenotype or blue-print was invented by Sir John Herschel in 1840.

It became the basis for the blueprinting of plans, a process that was used up until WWII.

Cyanotype was the third photographic technique after daguerrotype and talbotype (calotype), with which stable photographic pictures could be obtained. Unlike previous silver-based techniques, cyanotype is based on the light sensitivity of iron(III) complexes, which makes it comparatively inexpensive.

The process is based upon exposing to UV light, photosensitive chemicals that have been painted onto a substrate. The blue colour comes from the ferric element of the chemistry:

Ammonium  ferric chloride   + Potassium ferricyanide

The image is created by exposing the coated substrate:

     through a negative   (print)

     with light blocking objects  (photogram)

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The Chemicals and Safety

The chemicals used must be handled safely. With safe handling practices, making cyanotype is a user friendly activity.

The residual chemicals, after the paper is exposed are very dilute, and are unlikely to cause allergic reactions if they touch the skin. Gloves or tongs must be used when immersing the paper in the water bath.  Hands should be washed if any chemicals touch the hands.

The dry cyanotype print is quite safe to handle.