Sun printing is a form of photographic printing in which objects are placed on photosensitive paper and exposed to sunlight. This process is also known as cyanotype printing and was popularized in the mid-19th century. Some synonyms for sun printing include blueprinting, cyanotyping, and heliography. These techniques all involve using light-sensitive chemicals to create a photographic image, and they have been used for various applications, from creating fine art prints to reproducing technical drawings and maps. Whether you call it sun printing or by one of its many synonyms, this technique remains a popular and versatile way to create beautiful photographic prints.