Cyanotype
John Herchel is the inventor of cyanotype in 1842. The process incorporates the solutions of potassium ferricyanide and solution of ferric ammonium citrate. You place these light sensitive chemicals on a surface ( in this case paper) and then expose them to light. The UV light turns the iron(III) in the solution into iron(II) which leads to another chemical reaction. This creates a steel blue color that gets more intense (or more white) as more UV light hits it. The less UV light that hits it, the more blue it will remain. After exposure, the solution is washed off with water. Hydrogen peroxide is added to speed up the process. Note that the picture will only appear blue after leftover iron is washed off and is dried.
Chemicals used:
Ferric ammonium citrate 1 1 0 E
In case of eye contact:
Immediately flush eyes with plenty of water for at least 15 minutes.
In case of Skin contact:
Wash with soap and water immediately.
Potassium ferricyanide 1 0 0 E
In case of Skin contact:
Go to the nearest faucet and wash thoroughly with soap.
In case of eye contact:
immediately wash eyes for 15 minutes and get medical attention.
Chemicals used:
Ferric ammonium citrate 1 1 0 E
In case of eye contact:
Immediately flush eyes with plenty of water for at least 15 minutes.
In case of Skin contact:
Wash with soap and water immediately.
Potassium ferricyanide 1 0 0 E
In case of Skin contact:
Go to the nearest faucet and wash thoroughly with soap.
In case of eye contact:
immediately wash eyes for 15 minutes and get medical attention.
- When the emulsion was applied it was yellow.
- The sunlight's UV lights started turning iron(III) into iron(II) which reacted with other chemicals creating a grayish color.
- The areas under the object still looked yellow. This is due to the UV light never hitting the solution.
- The gray exposed areas turned blue as the iron had fallen off and the unexposed yellow turned white as all solution fell off.
- The hydrogen peroxide sped up the process of the iron coming of the paper as they attracted the iron.
- The picture in the cyanotype is in blue and white. The paper feels as rough as it had originally. The process is not a practical form of recording photos.