Interesting history of photoengraving

Wood engravings are considered to be the earliest engraved printing units.

The famous known illustrations printed from woods are as follows:

Early etching techniques and materials

In addition to engraving on wood to form printing plates in the late Middle Ages and early modern periods, plates made of copper, pewter and other metals also began to appear. This was done by coating metal plates with a resist substance such as wax, bitumen, or shellac, scraping this substance (the ground) to expose the plate surface, and then etching with acid, developed as a medium of artistic expression.

Joseph Nicéphore Niepce of France made the fist permanent photograph in 1813. In 1826 he applied photosensitive asphaltum to a copper plate or a pewter and exposed the surface to bright sunlight by etching the portrait. the sunlight passing through the etching background hardened the asphaltum, and the protected area in the inked area of the etching developed in lavender oil and white petroleum, thus forming an image in the exposed metal, which is then etched into the plate to form a gravure image that can be printed on a copperplate press.

This important discovery did not immediately bring about the use of photolithographic images for printing, and many other attempts were made by European and American experimenters to make prints using the photosensitivity of various natural compounds. However, the real origin of the modern photographic process making process comes from the report (1839) of a Scottish scientist and inventor, Mungo Ponton, who discovered the property of certain chromium compounds to undergo chemical changes by the action of light. The English photographer William Henry Fox Talbot proposed the use of chromium-treated colloids (e.g. albumin) as an etchant-resistant for preparing intaglio surfaces.

Early work on producing chemically etched letterpress plates in the 19th century predated the invention of photography. A researcher in Paris used ink or wax to mechanically transfer images onto a zinc plate and remove non-printed areas in a series of etching operations, each of which involved applying a layer of ink to the sidewalls of the etched lines by means of a flexible roller. The ink serves to protect the engraved lines from the etching acid effect so that the printed area is not reduced.

Invent of Wet-collodion photography

In 1851 the wet collodion process was invented to prepare engravings. In this process, the glass plate is coated with a solution of an alcohol-ether solution of collodion (cellulose nitrate) containing potassium iodide. It is then immersed in a silver nitrate solution, thereby producing light-sensitive silver iodide in the collodion layer. The plate is exposed and developed through a ferrous sulfate solution to produce a greater opaque image. This photographic process also provided a method of stripping the photographic image from the glass plate, which was used until the 1930s. It is now gradually being replaced by commercially available coated coated stripping films.