The Cyanotype has been one of the more popular of the Alternative processes, in part due to the relative simplicity of its creation but also due to the lower cost and safety of the materials used, plus the flexibility of print surface mediums from paper to fabric, in fact almost anything is possible (within reason).
The Cyanotype was originally developed in the 1840's by scientist Sir John Herschel as a means of creating and reproducing scientific illustrations long before before photocopiers came along and they have the characteristic Cyan (Blue) base colour. This very soon become known as a Blueprint, a term still used today to depict an original design.
In later years a newer 'faster' process has become popular but many artists still use what has become affectionately known as the original 'Herschel' formula.
Cyanotype test prints ...
Similarly the Van Dyke shares some of the process methods with the Cyanotype from which it was developed but has a very rich dark tone and takes its name from the Flemish painter Anthony van Dyck who favoured a rich dark brown colour in much of his work.
What I love about the Van Dyke print is the deep dark tones and high contrast but retaining some of the grey scale often lost with Cyanotype. Van Dyke formular produces an intense moody image, just what I like.
Some of my earlier Van Dyke prints ...