Carbon transfer and carbro printing need “tissue”. This is a sheet of suitable material coated with gelatine containing a suitable pigment. Already this short description has many variables . Which gelatine, what material, the type of pigment.

I have not found anyone who supplies ready made tissue and even if I did I doubt I could afford it. Custom made products for “alternative” photography attract a high premium. I do a lot of tests and experiments so I have to find a way of making all materials myself and from inexpensive sources.

The material I use are sheets of clear polyester (mylar). I have found that a size slightly larger than A3 is about right for most of my printing. I can cut this to most practical sizes for the carbon processes. These sheets need to have  a surface which can hold the gelatine emulsion on without it peeling off when it drying in my drying cabinet.  I also need this material to be able to release the glatine profile,clean and evenly when I make a double transfer.

The material often recommended for tissue is Yupo, I agree that this is excellent but it is expensive, I have not found a local supplier who supplies a transparent version of Yupo. I have found a simple source of polyester sheets. I buy the laminating sheets supplied by office equipment firms for their plastic laminators. These sheets can be bought from 80 gram to 250  gram weight and each sheet gives two perfect, slightly bigger than A3 pieces which have a “key” on one side and are perfectly clear and smooth on the other side. Our local supermarket sells these in packets of 20 sheets, giving 40 pieces of A3 material for under 3 euro. I have been using this material for three years with no problem and often find boxes of 250 sheets at car-boot and garage sales for a few centimes.

Gelatine is easy, Amazon sells 1 kg tubs of 250 bloom halal or kosher (from beef) gelatine for about 20 euro. I would like to buy photographic gelatine, but this works out at five times the price. So far I have not had a problem with this.

Making the pigment is a challenge. I use good quality indian ink for orotones, I have tested many makes, they vary considerable in density and colour – I prefer a browny black for orotones, but I am looking for something nearer a mars black for the colour work.

To make a tissue, I usually mix 50 grams of gelatine in 500 ml of cool distilled water and let it stand for 30 minutes. I then slowly heat in a water bath up to 41 degree celcius. When it is fully liquified I add 35 grams of white sugar, 10 ml of glycerine, 10 ml of isopropyl alcohol, 6 drops of thymol and the colouring pigment ( or ink).

I reheat this back to 41 degree C and then decant this into 4 equal parts in glass jars. I remove the caps of the jars and put them in a heat controlled vacuum chamber and leave it in for  30 to 40 minutes.

While the vacuum pump is on, I layout 3 sheets of my laminate polyester on a clean glass table which is absolutely level. I spray the table with distilled water and the squeegee the polyester sheets flat onto the damp glass with no air bubbles. To keep the pigmented gelatine on the sheets of polyester I put strips of light aluminium angle on the edges of the polyester sheet; to keep it in place I moisten the edge of the aluminium resting on the plastic sheet.

Once the jars of pigmented gelatine have been in the vacuum chamber to get degassed, I gently stir and check the temerature is at 40 degrees C – I then pour the measured jar, which has one quarter of the 500 ml mixed “glop” , pour it carefully onto an A3 sheet and comb it evenly over the surface with a warmed aluminiun comb (ordinary comb for the hair). I cover the sheets with frames to avoid dust settling and put ice bags uner the glass surface to cool the sheets.

The gelatine sets enough in about 30 minutes so I can transfer them to my drying box. This rying box was cobbled together from an old cooker hood, ventilation pipes, a swimming pool fliter, coat hangers and storage boxes – I originally used wooden tea chests, but they are antiques now so plastic storage boxes work fine.  The tissues in the drying box dry overnight with the extractor fan running.  I usually make 3 or 6 A3 tissues each working day, but I can make a larger batch by assembling a simple tower of plate glass sheets with large lego blocks to separate each layer – I use lego a lot for photographic work as each block is dimensionally accurate and keeps the layers of glass level.

The amount of pigment used for each A3 sheet of tissue depends on the colour and make. There seems to be a huge variation; I use from 4 gram to 30 grams per sheet depending on the requirement. Pigements are a issue I will write about.