The resinotype process

Alberto Novo takes us through the resinotype process from beginning to end.

Always be careful when handling chemicals. Read the health and safety instructions.


I must state beforehand that I am not a master of resinotype: I started experimenting this technique some months ago as I wanted to produce prints with a distinctive velvety aspect, and the only images I have seen with these characteristic were resinotypes. While working, I needed to know more about this process never fully explained, and I have been able to gather many useful information both technical and historic from original papers.

The four images are part of a complex project I am developing about Venice: for the courtyards and "campielli" I wanted a green colour, inspiring the humid mossy shadow, and I found the chromium oxide well fitting that look. These are my first monochrome proofs, but I am planning to add some brown in the deepest shadows and blue in the highlights.

The resinotype had its maximum diffusion in the period 1922-1935. Its inventor, Rodolfo Namias (1867-1938), adapted and enhanced the well known powder process (Garner and Salmon 1958), though the variation introduced by Sobacchi in 1879 looks much more similar.

Namias wrote that

"The resinotype was born from the observation of an anomaly. In my researches on the chemistry of the transformation of the silver image for a better application of bromoil I noted that, using an ink made very hard mixing it with lamp black, the ink was better retained by the swollen parts of the image rather than the more hardened ones. From this I had the idea that a not insolubilised gelatine could be able to retain a resinous and greasy particulate matter better than the insolubilised gelatine".

Compared with the classical "dusting-on" process, the resinotype was giving less muddy and more vigorous images, preserving the characteristic velvety aspect and allowing a large possibility of manual intervention on the image.

The process was patented in 1922 (or earlier, as at present I am not able to find the patent in the Italian archives) as "Resinopigmentipia", but this name was contracted in the simpler "Resinotipia" in 1923, and a few years later was produced also the "bromoresinotipia". Namias began to advertise his process, making and selling paper and powders which were sold through Il Progresso Fotografico, the same firm printing the first Photography newsletter in Italy (1894). A national contest reserved to resinotypes was held in Chieti in 1926.

Despite its success, chiefly in Italy, the resinotype was abandoned after about 15 years. The declining interest towards the pictorialism, the death of Namias in 1938, the never given instructions on how-to prepare at home the materials, and the particular historic, economic and politic period before the Second World War not so favourable for Italy, all contributed to forget this process.

In all the six editions of La technique photographique of L.P. Clerc, edited between 1926 and 1957, there is a description of the "resino-pigmentype" (the original name of resinotype), but in the following editions of Chimie et Physique Photographiques of P. Glafkides about twenty years later there is a text of only two rows.

The late 1970 and early 1980 is a period of discovery of the old and alternative processes in Italy (the constitution of the Rodolfo Namias Group dates 1991), and the resinotype was "re-invented" by some Italian photographers independently each others, with some variations due to the uncertainty of the written sources, and is still practised by three or four people (or this is what I have been able to ascertain).

In France, Alfons Alt set up his "resino-pigmentype" in 1993, having Clerc as a source of information, but introducing some personal variations.

The process can be shortly outlined in this way:

Procedure

1Preparation of the powder : melt a mixture of pigment and colophony (rosin) about at 25-30% by weight. Grind the fused mass and sieve the powder. The diameter of the particles is critical, because the finer particles are able to adhere also to the whites, and the bigger particles give a grainy appearance. Choose pigments stable with heat, and unable to react with the hot colophony; this last contains about 70% of abietic acid. The characteristics of the powder depend also on the concentration and the type of the pigment.

2Preparation of the paper: choose a medium-weight paper and seize it with a 8-10% gelatine solution, like for an oilprint. The gelatine must not melt, once swelled in water, below 30°C.

3Sensitising: a solution of 4% potassium dichromate by immersion, or a 4% ammonium dichromate in 50% ethyl alcohol (to be freshly prepared) by brush.

4Exposition: under UV light, with a positive (a RC print is perfect), until a brown image forms in the darker zones. The sensitivity is about double compared with a gum dichromate.

5Washing: about 2 hours in cold water, but it may be much more longer (up to 8 hours) until the yellow dichromate stain will completely wash out.

6Swelling: about 2 minutes in hot water. The temperature must be about 1 or 2°C below the melting point of the swollen gelatine, then wipe off the surface water like for a bromoil.

7Powdering: distribute the resinotypic powder over al the surface of the print, like pouring the sugar on a cake. Brush the powder here and there with a very soft brush helping the powder to adhere, then remove the excess of the powder by gently tipping the print, hold vertical with it support.

8Retouching: use dry or only wet brushes from this point up to when the print is completely dry. This allows for a variety of interventions because the powder begins to adhere more whilst the surface dries. The wet brush removes the powder to a white surface.

9Removing of the veil: a residual veil can be removed after the print is completely dry, pouring it in cold water and brushing it underwater. Further retouching may be applied.

10Removing of the dichromate stain: use a cold solution of 5% potassium or sodium metabisulphite after the complete dryness of the print. This step can be coupled with the previous one.

11Fixing: expose the dry copy, on both sides, to the steam coming from a boiling pot. This partially melts the resin but preserves the velvety aspect of the print. One can also put the print in an oven, or spray a 2% solution of shellac in alcohol, but in this way the resin melts and the print will have a glossy look.


Reader’s comments on the processes

Great write up. > > well done > > nice layout.


3 Comments

  1. Posted May 17, 2010 at 11:14 am | Permalink

    bonjour , je suis interesse du procede en poudre de resine , mais je vous posse une question … pour melanger de la resine et le pigment … vous dite un melange de 25% a 30% ?? alors cela veux dire par exemple je mets 100grs de resine et je prend 25 grs de poudre est ce cela ??? et chauffe a quel temperature ??? en attendent de votre reponse merçi

  2. Alberto
    Posted May 18, 2010 at 10:40 am | Permalink

    Désolé, mais ne parlent pas français. Il s’agit d’une traduction automatique.
    Un mélange de 30% est constitué de 70 grammes de résine et 30 de pigment.
    Vous avez à la chaleur du pot d’aluminium dessus d’un filet en remuant avec une tige de verre ou de bois. La résine est presque liquide à 120°C.

  3. Posted October 5, 2010 at 4:35 pm | Permalink

    buongiorno, per fare del resinotype , bisona avere film positivo contrasto normal ? alto? dolce? … Puo farsi con la cartefoto argentique black+white baryte olivastro? semi olivastro? gliaccio?… amicalement

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