William Henry Fox Talbot (1800–1877), a British scientist, linguist, and mathematician, invented the calotype process in 1840–1841 at his Lacock Abbey estate, spurred by frustration with his own sketching limitations during a 1833 Lake Como trip and the 1839 public Daguerre daguerreotype announcement. This drove him to refine his earlier "photogenic drawing" experiments into the first negative-positive paper system, enabling unlimited prints from one exposure. "Calotype" derives from Greek kalos ("beautiful") and typos ("impression"), meaning "beautiful impression."​

The five-step calotype workflow began with iodizing writing paper under candlelight using silver nitrate and potassium iodide to form light-sensitive silver iodide, followed by washing and drying. Talbot then sensitized it with a "gallo-nitrate of silver" solution (gallic acid plus silver nitrate), dried it again, and loaded it into a camera obscura for brief exposure (1–2 minutes in sunlight), creating a latent (invisible) negative image. Post-exposure, chemical development with gallic acid brought out the full negative on translucent paper—often waxed for clarity—allowing contact printing of positive salted-paper images with rich tones, though paper fibers gave a characteristic softness unlike sharp daguerreotypes.​

Talbot eagerly applied calotypes to botanical documentation at Lacock Abbey, producing photogenic drawings and early negatives of plant specimens like leaves, flowers, and orchids placed directly on sensitized paper or captured via camera. These contact prints or slight camera views preserved exact outlines, textures, and vein patterns without artistic interpretation—ideal for scientific records of plant morphology—shortening exposures from hours (his prior photogenic drawings) to minutes and surpassing hand-drawn illustrations in fidelity. He shared the process freely for scientific use, including photomicrographs of crystals and insect wings, laying groundwork for botany's visual archiving.