A Illustrated Guide to Platinum Printing
A step by step guide to producing a platinum / palladium print using the dichromate method.
- Preparing the paper
I print most of my platinum prints on Arches Platine watercolour paper, which is specifically designed for platinum and other alternative processes. Tear or cut down to a size that leaves 2-3 inches around the print, then mark the corners of the negative with light pencil marks to make coating the paper more accurate. - Mixing the sensitiser
To make a 9×6 inch print the platinum / palladium sensitiser is made up from:
- Ferric Oxalate – 10 drops
- Palladium in the form of Sodium Chloropalladite 15% solution – 7 drops
- Platinum in the form of Potassium Chloroplatinite 20% solution – 3 drops - Coating the paper
The sensitiser is drawn up into a small syringe and then applied in a continuous run along one side of the paper. Then take a coating rod (a brush can also be used) and spread the sensitiser across the paper following the pencil outlines. You should get between 6 and 10 passes to give a nice even coat, any excess can be mopped up with a cotton bud. Once coated the paper is left to dry in the dark.
- Holding the paper and negative
The negative is now placed on the coated paper and held firmly together using either a contact printing frame, a vacuum frame or two heavy sheets of glass.
- Exposing the print
The negative and paper sandwich is then placed under the UV light source and exposed, exposure times can vary between 5 and 10 minutes using a bank of black light blue fluorescent tubes, other light sources may require different exposure times.
- Developing the print
The print is the placed in a tray and Potassium Oxalate developer is poured over the print. The print is then developed for 2 minutes with constant agitation.
- Clearing the print
Clearing the print involves 3 baths of hypo clearing agent (EDTA can also be used). The print spends 5 minutes in each bath, the first with constant agitation the second with intermittent agitation and last with no agitation.
- Washing the print
The Print is finally washed in running water for 30 minutes before being hung to dry.
Thats it, once dry you have a platinum / palladium print that can be mounted and framed as required.
An Introduction to Salt Printing
Salt printing is one of the oldest alternative photographic processes and while it may not be as well know as processes such as platinum and cyanotype it is still very rewarding and produces exquisite prints. The salt printing process was invented by William Henry Fox Talbot who had been experimenting with paper negatives trying to create a printed out image, the first ever salt print was made by Talbot at Laycock Abbey in Wiltshire, UK and was just a picture of one of the window frames in the abbey. Although originally known as the Calotype process it now seems more commonly known as salt printing or the salted paper process.
A salt print has a unique eggshell / faint aubergine tone to it with a high degree of sharpness and contrast although lower than platinum and other iron based process. The print has a wonderful openness to it with extended shadow detail and soft highlights, it almost looks three dimensional.
To create a salt print we first have to coat a sheet of watercolour paper with a salt solution and once this has dried a coat of silver nitrate is applied, these coating can be applied with either a glass coating rod or a brush, after the second coating has dried the sensitised paper is ready to be exposed. As with other alternative printing processes the sensitiser is very weak and requires and high power UV light source to expose, this can be the sun as Talbot did or you can use a artificial UV light source, you then need a negative the same size as your required print so it can be contact printed under the UV light. Traditionally Talbot used paper negatives but large format camera negatives and inkjet negatives can be used too.
The sensitised paper and negative are sandwiched together under a sheet of glass and then exposed to the UV light source. Salt printing is a printing out process also known as a POP which means the image will start to appear on the paper and darken as the exposure continues, this is useful if you are using the sun and trying to determine the correct exposure – ideally you want the exposed print to be one stop darker than you would like.
Once the paper is exposed it is placed in a tray of warm water and agitated for around five minutes, this develops the print and will lighten it slightly. The print then passes to a tray of sodium thiosulfate this removes the remaining silver nitrate and fixes the print making it no longer light sensitive and again lightens it slightly. The final step is to wash the print for thirty minutes before drying, mounting and framing.
While a correctly fixed salt print will last for many decades it is common practice to tone salt prints to increase longevity common toners include gold, platinum and palladium – once archivially toned the print will last indefinitely. Each toner has its own characteristics and how it effects the print, for example gold toning will cool down the print and create a burgendy / blue hue, platinum and palladium toners will give the print a warmer brown or sepia tone. The effect of the toner depends on the how long the print is left in the toner, commonly anywhere between five and thirty minutes – although the effect is usually quite subtle. The toning bath can be done before the sodium thiosulfate fixer bath, then fixed and washed as usual or the print can be done after fixing although the print will need fixing and washing again after toning.
Toning Cyanotypes With, umm Tea!
It might sound strange but tea can be used to tone prints and works especially well with cyanotypes imparting a yellowy red tone to the highlights of the images and creating almost split toned effect which can be quite effective. Tea has a naturally high tannin content and it is these tannins that tone the print.
To mix up a bath of tea toner, brew around 5 tea bags in a litre or quart of hot water (the tea bags diffuse quicker in hot water). The tea toner can be reused time and time again and works the same whether hot or cold. The time required to tone a print can vary from ten minutes to many hours, it just depends on the strength of the tea and the effect you are looking to achieve. As with a lot of alternative photographic processes there is no hard and fast some tests are the best idea.
Above is an example of the effect created when toning with tea, the print on the left is the untoned traditional cyanotype and the one on the right has been brewed for a couple of hours in the tea toner. A shorter time in the tea will give a more subtle effect. A second option involves first bleaching the cyanotype print in a weak solution of sodium carbonate, this removes much of the blue tone and as a result the tea toning will redevelop the print with more of a black colour.
This is a great use for those decaffeinated tea bags you have lurking at the back of the cupboard although there is a slight concern when toning with tea, it makes you realise what tea does to your insides. 
An Introduction to Platinum / Palladium Printing
Platinum printing is perhaps the most desirable of all the alternative (non-silver) photographic processes, the printed image rather than being made of silver as in a traditional darkroom print is made up from platinum and usually palladium metals. Before the first world war it was possible to purchase platinum coated paper just as we now buy silver geletin paper, however platinum became a precious metal and was used in ammunition hence the paper was stopped and has never been continued.
This means that in order to create a platinum print you have to coat the platinum solution on to your paper before you can make a print. The platinum solution is mixed from a number of chemicals although there are different ways to make a platinum print and therefore various chemical makeups, however throughout this blog I am going to stick with the method I use and have been very satisfied with, this is known as the dichromate method and is very similar to the method used by William Willis’s patented 1873.
The platinum solution also know as a sensitiser is mixed from Potassium Chloroplatinite (platinum), Sodium Chloropalladite (palladium) and Ferric Oxalate. This solution is then coated on to a sheet of high quality watercolour paper using either a glass rod or a brush, once the paper has dried it is ready to be printed.
The platinum sensitiser is very weak and as a result cannot be printed using a standard darkroom enlarger, it requires a high power UV light source such as the sun (as originally used) or an artificial UV light source which I will cover in a later post. This also means that the only way to create an print is to contact print the platinum sensitised paper with a negative the same size as the final print. Traditionally large format cameras were used to create negatives however it is possible to make enlarged negative is the darkroom or with the help of digital technology (more on this later).
Once the sensitised paper has been contact printed and exposed the print then needs to be developed in a bath of Potassium Oxalate, as soon as the developer comes into contact with the exposed sensitiser the print appears almost magically – I never get tired of watching this wonderful process. Once developed the print then has to be cleared to remove any traces of salt and iron from the sensitiser both are very harmful to the longevity of the finished print. The clearing process involved washing the print in three baths of either EDTA or Hypo until the yellow stain has gone.
The final step now is to wash the print in running water for thirty minutes before hanging it up to air dry. The print can then be mounted and framed as necessary using museum quality acid free materials to ensure the print is protected.
This may sound like quite a length to go to just to produce a single print however there is nothing like looking at a handmade platinum print. The print has a unique beauty and quality to it, the delicate rich tones range from warm black, through reddish brown, to expanded mid-tone grays that are unobtainable in silver prints. The deepest shadows still have detail and the whites are soft and delicate; the depth of the image is alive and three-dimensional. Platinum prints are not only exceptionally beautiful, they are the most durable of all photographic processes. The platinum and palladium metals are more stable than gold, and it is estimated that a platinum print, can last thousands of years.
A World of Alternative Photographic Processes
An alternative (non-silver) photographic process is loosely defined as any traditional or historic analog (although I don’t like the term analog) printing process that does not use silver gelatin paper that is commonly used in traditional darkroom printing. There are many alternative processes such as platinum, cyanotype, vandyke, gum bichromate, kallitype, ziatype and salt printing to to name just a few, but the list goes on and on. Each alternative process has its own printing characteristics however they all follow a similar printing methods.
With alternative (non-silver) photographic processes rather than buying pre-sensitised paper such as silver gelatin paper you have to hand coat the required sensitiser on to a sheet of watercolour paper, this coating is usually brushed or applied with a glass coating rod. Once coated the sensitised paper is contact printed with a negative the same size as the finished print under a powerful UV (Ultra Violet) light source. If you live somewhere nice and sunny you can use the sun, but here in the North of England a better option is a bank of black light blue fluorescent tubes, although there are other light sources that can be used too.
Each alternative photographic processes has its own characteristics such as tonal range and even the colour of the print that is produced, this often means that not all processes will work for all photos although you do have the flexibility to choose a specific process to match the mood of the photo.
I have been experimenting with various alternative photographic processes and in the image below I have taken one of my favourite photos of Gannex Mill and printed it using six different alternative photographic processes to illustrate the differences.
Top row – Platinum / Palladium, Argyrotype & Cyanotype
Bottom row – Gum over Palladium, Gumoil & Cyanotype toned in tea
Not only are there various alternative photographic processes but these can be altered by toning the print, the two the right most examples these are the same print but the one on the bottom line has been toned in tea. If toning still doesn’t give you enough variables then it is possible to even combine multiple processes together, the print bottom left started out as a Palladium print but was then give a wash of colour using the Gum Bichromate process. It is this flexibility in that allows you imagination to be only limits in what you can achieve.
Each alternative printing process has different material costs to go with it. Platinum prints sit at the top of the pile and cost £2/$3 to make a small 7×5 inch print and a 10×8 may cost double this, at the other end of the scale are cyanotypes and gum prints which can only cost pence to make. Many people start out printing using cyanotype or vandyke process as it is lower cost and allows the printer to learn the basic techniques behind creating an alternative process print, although I just jumped into the deep end with Platinum.
