Towards an Unproblematic Cyanotype Chemistry
The 'Classic' cyanotype process relies unsatisfactorily on an impure chemical, ferric ammonium citrate. My 'New' cyanotype sensitizer of 1995 overcame this problem, but at the price of more demanding chemistry. A third option, the 'Simple' cyanotype, has now (2019) been devised - easy to make up with pure chemicals - and offering a control of contrast not hitherto possible.
Paper for Alternative Printing
Possibly the greatest problem confronting alternative process workers is finding a paper suited to their purposes. Of the numerous commercial high-quality papers on the market, very few 'work' well. This is an account of how criteria were evolved, in collaboration with the skilled hand-papermaker of Ruscombe Mill, which resulted in a sheet that performs superbly with all the iron-based processes.
Chemistry of the Iron-based Processes
This is an attempt to de-mystify the inner workings of these process for non-scientists, by explaining the chemical jargon and equations in accessible language.
An Investigation of Platinum and Palladium Printing
A technical paper on research into the chemistry of these processes, with a quantitative assessment of the differences between them. The importance of controlled humidity in achieving a reliable printing-out method is described. The effects of additives such as mercury(II), lead(II) and gold(III) are also discussed.
Photographic Printing in Colloidal Gold
A technical paper on the novel coordination chemistry that underpins my New Chrysotype process, whereby gold(I) can be stabilised in a ferrioxalate sensitizer. It also offers an explanation of the wide range of colour that is achievable with this process.
The Choice of Cation in Ferric Print-out Processes
For print-out processes, where the image is substantially formed during the exposure, the water content of the sensitized paper is of the utmost importance. This is, in turn, governed by the ambient relative humidity, but also by the chemical nature of the cations present in the sensitizer, for which ammonium is argued to be the best choice.