Are interesting because they keep some of their light-sensitive properties and can therefore appear to be washed out over time. this condition can be reversed, however, by returning it to a dark room.
a. cyanotype
c. daguerreotypes
b. digital images
d. photogravures

The Correct Answer is A

Explanation:

Cyanotype is a graphic presswork method that originates from a cyan-blue print. Designers practiced the method well into the 20th era as an uncomplicated and low-cost method to generate prints of pictures, mentioned to as plans. The method employs two substances: ferric ammonium citrate and potassium ferricyanide.