Bob Cnoops

  • bob cnoops_1


Photograms are essentially photographs made without the use of a camera: camera-less photographs. By placing an object on light sensitive paper and exposing this to light, will produce an image on the paper. Mostly this is done in a darkroom where the light can be controlled with safelights and exposure lights. After exposure, the paper is treated in different chemical baths which will develop and fix the image.

Bob Cnoops has used an antique printing process, the Van Dyke Brown printing process, obsolete since the 1860’s, to produce his photograms. The light sensitive emulsion is hand-made and hand-applied to water-colour paper. When the emulsion is dry the object is placed on the paper and exposed to ultra-violet light. Different light-sources will produce different results. The finished print is deep brown due to the chemicals used in the emulsion. If treated correctly in the chemical baths, the Van Dyke Brown prints are highly archivally permanent.



The Argento-Ferrotype process, also commonly called the Van Dyke Brown Process, is a photographic process that was already obsolete by the mid 1800’s. This was as a result of rapid advances in photographic film~ and paper technology. Since then the process has been used sporadically by enthusiasts of the process, primarily for pictorially aesthetic purposes. With the rekindling of interest in the old “Alternative” processes in the last decade the Argento-Ferrotype process has once again regained its status as one of the most beautiful photographic processes ever invented. It has the added technical advantage of having a superior archival permanence (a very long-lasting life expectancy in proper storage conditions, before atmospheric deterioration). It has recently been ascertained that particular 19-th century prints, up to now believed to be Platinum Prints (accepted internationally as being amongst the most archivally permanent photographic prints), were in fact Argento-Ferrotypes, thereby confirming their permanence.

The name Argento-Ferrotype is derived from the fact that the image is formed by a compound of silver and iron, as opposed to the common silver image in conventional Black/White photographs.

The prints by Bob Cnoops have all been archivally processed and printed on superior Fabriano 280 Gsm. watercolor paper. The light-sensitive emulsion was hand mixed by Bob and applied to the paper with Japanese Hake brushes to ensure maximum cleanliness and minimum contamination. After years of intense research and experimentation, Bob has achieved a level of quality in his Argento-Ferrotype printing seldom seen with even the most experienced international practitioners of the process.

Bob has also had extensive experience with two other Alternative processes, namely the Cyanotype Process (in which the image is a rich Delft blue) and the Oleo-Pasto Process (whereby the photographic image is formed by painters’ oil colours).