In collaboration with Daniel Heikens - Photography expert
In a world where our phones double as our cameras, it’s nice to look back at photography from the past and how the technology has developed over time. In the late 1800s and early 1900s a method of printing arose due to an increased demand for high-quality photographs. Rather than developing photosensitive material to produce just one photograph, moulds and printing plates were created from photographs, allowing for mass production and sometimes even have nicer tones than gelatin silver prints . Keep reading to find out how photomechanical printing works and what the results look like.
What is Photomechanical Photo Printing?
This process, as the name implies, involves generating an image photographically, but printing with ink on paper rather than with photosensitive material. It can be thought of most simply as an early bridge between the analogue and digital ages. This process could be completed a number of way, but the basics (without getting too technical) involved chromated gelatin, which would harden in exposed areas creating topographical variations which matches the tones in the image. From this a mould could be created and printing could begin en masse, similar to printing press methods. Let’s explore just a few methods and how exactly they work
Photogravure
This technique encompasses many photoetchings or ‘gravures’. In this process, the gelatin is used as a resistant in etching a metal plate from which prints would be produced. After being exposed, the gelatin is pressed into a resin-dusted metal plate. The unexposed gelatin is washed away and the plate is etched. Acid eats away at the metal unprotected by gelatin leaving an etched plate which can be printed from.
The print shown above was printed using the intaglio technique. This required the entire etched plate to be covered with ink, and then wiped off, leaving ink only in the etched recesses which would then be transferred to the paper.
Photoengraving
Virtually the same process as creating a photogravure could create a photoengraving. The difference lies in the plates. Photogravures are created with intaglio plates. The sections to be printed are removed from the plate and the ink to be printed in in the recessed etchings on the plate. Photoengravings however use relief plates, which are the exact opposite, the sections which are not to be printed are removed from the plate and the ink is on the remaining relief sections.
Heliotype
While some printing techniques used the gelatin relief to create a mould for printing, some used the gelatin itself. Because gelatin is rather delicate, only a limited number of truly good prints could be produced. The heliotype technique used a gelatin that was 5 times harder, combating this problem. So how does it work? Exposing the gelatin to light not only hardened it, but also caused it to become hydrophobic (resisting or not mixing well with water) which in turn allowed it to pick up oily inks better. The gelatin that was less exposed was not as hydrophobic as exposed sections, and therefore did not pick up the ink creating tonal differences quite similar to the lithography process.
There are many other photomechanical printing methods, we’ve just focused briefly on three. Now that you know how this printing method works, have a look at our unique Vintage Photomechanical Prints auction for more examples of fine vintage prints from the turn of the century. Photomechanical prints have one very big plus compared to gelatin silver prints: they are very stable and have a long date of expiration. They do not fade, get silver mirror etc. so now is the time to place your bids on one of these vintage treasures. This special auction will end on the 1st of September, 2017.