Raphael Eduard Liesegang () (1 November 1869 – 13 November 1947) was a German

chemist A chemist (from Greek ''chēm(ía)'' alchemy; replacing ''chymist'' from Medieval Latin ''alchemist'') is a graduated scientist trained in the study of chemistry, or an officially enrolled student in the field. Chemists study the composition of ...

, photographer and

entrepreneur Entrepreneurship is the creation or extraction of economic value in ways that generally entail beyond the minimal amount of risk (assumed by a traditional business), and potentially involving values besides simply economic ones. An entreprene ...

born in

Elberfeld Elberfeld is a municipal subdivision of the Germany, German city of Wuppertal; it was an independent town until 1929. History The first official mentioning of the geographic area on the banks of today's Wupper River as "''elverfelde''" was ...

. He is known for his work on Liesegang rings. He also helped develop the methods of capillary analysis, a precursor to

paper chromatography Paper chromatography is an analytical method used to separate colored chemicals or substances. It can also be used for colorless chemicals that can be located by a stain or other visualisation method after separation. It is now primarily used as ...

, published a paper on the possibility of

television Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...

(years before the discovery of the electron), contributed to chromosome theory, worked on properties of

aerosol An aerosol is a suspension (chemistry), suspension of fine solid particles or liquid Drop (liquid), droplets in air or another gas. Aerosols can be generated from natural or Human impact on the environment, human causes. The term ''aerosol'' co ...

s and

gelatin Gelatin or gelatine () is a translucent, colorless, flavorless food ingredient, commonly derived from collagen taken from animal body parts. It is brittle when dry and rubbery when moist. It may also be referred to as hydrolyzed collagen, coll ...

s, the origins of

silicosis Silicosis is a form of occupational lung disease caused by inhalation of crystalline silica dust. It is marked by inflammation and scarring in the form of Nodule (medicine), nodular lesions in the upper lobes of the lungs. It is a type of pneum ...

, the role of

carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...

in plant life and the mechanism of both

black and white Black-and-white (B&W or B/W) images combine black and white to produce a range of achromatic brightnesses of grey. It is also known as greyscale in technical settings. Media The history of various visual media began with black and white, ...

and colour photographic processes. The son of a painter (and eventual photographer), Liesegang longed for an artistic career but lacked the ability to draw or paint. His father would later invent a camera and photography would go on to be one of Liesegangs passions. Research into

photographic emulsion Photographic emulsion is a light-sensitive colloid used in film-based photography. Most commonly, in silver-gelatin photography, it consists of silver halide crystals dispersed in gelatin. The emulsion is usually coated onto a substrate of gla ...

s led to his personal discovery of Liesegang rings. He was not the first person to observe the effect, but they bear his name, as he devoted so much time to researching them. As an heir to the founder of Ed. Liesegang oHG,

Düsseldorf Düsseldorf is the capital city of North Rhine-Westphalia, the most populous state of Germany. It is the second-largest city in the state after Cologne and the List of cities in Germany with more than 100,000 inhabitants, seventh-largest city ...

, he also owned a factory producing

photographic paper Photographic paper is a coated paper, paper coated with a light-sensitive chemical, used for making photographic prints. When photographic paper is exposed to light, it captures a latent image that is then Photographic developer, developed to form ...

and chemicals. Ed. Liesegang oHG later expanded into optics manufacturing, and sold its photochemical interests. He has published the first German brochure on television
''Beiträge zu Problem des elektrischen Fernsehen''
1st edition 1891, 2nd edition 1899

References

* * Heinz K. Henisch, Crystals in gels and Liesegang rings
Le grand chimiste allemand Raphael Eduard Liesegang contribue à la question de la télévision électrique, "problème du présent" (1889–1899)
19th-century German chemists 1869 births 1947 deaths 20th-century German chemists People from Elberfeld Scientists from Wuppertal Businesspeople from Wuppertal {{germany-chemist-stub