Is there a method to improve the longevity of cyanotype prints? Cyanotype is basically the archaic blueprint process developed in ammonia, isn't it? Frequently I see images that have been stained in tea, coffee or other liquid. Besides the altered appearance, does the staining improve the permanence of the prints? Demos I have seen use ultraviolet light source in the darkroom to expose the print paper or sunlight can be used.

cyanotype is one of the oldest and most permanent photo processes. The basic chemicals used are Ferric ammonium cirate and potassium ferricyanide. The cheapest method of exposure is sunlight. then washing in water.

THe use of tea, and other toning combinations is in an attempt to get away from having every print prussian blue,not an archival process.

IIRC, Cyanotypes are actually pretty stable. Archivability isn't quite an issue.

And after developing, a solution of household peroxide and water will help bring out the "fullness" of the image.

Thanks for the info. It seems that paper selection is important for permenance. Some papers yellow and deteriorate more quickly.

Paper is VERY important. Good quality art paper is best. Lasts forever. Anything used for Pt/Pd printing should be fine.

Actually, cyanotype is sensitive to alkaline conditions, so it wants a good quality, unbuffered, paper.

Don't forget to keep your cyanotype in unbuffered boxes. and don't used any buffered paperto matt and anything closed to the image.