Carbon-gelatine is a printing technique developed by Mantinieri with the goal of producing fine art prints that will surpass traditional silver-gelatine and gicleé prints in terms of longevity.
Carbon-gelatine printing is accomplished through the following steps:
The whole process is completely hand-crafted by the artist: each print needs several days of work and drying in order to be completed. Three elements contribute to give Carbon gelatine prints their permanence: the paper medium, the inks and the final coating.
The medium used for carbon-gelatine printing is 100% cotton, uncoated fine art paper. Several brands are used, each one carefully chosen to maximize the rendition of that particular image. Here is a list of the fine art papers he mostly uses:
Modern inkjet papers that are commonly used today to produce gicleé prints can hardly stand the longevity of pure rag, fine art papers. Their coating contains, indeed, a considerable amount of different chemicals intended to retain the ink and to enhance the image. The stability with time of such coatings is still undemonstrated. This is true also for inkjet papers using a 100% cotton supporting medium and advertised as a "archival". The coating of inkjet paper is mainly used for accelerating the process of printing in commercial labs and, in most cases, it would also enhance the contrast of the image by increasing the depth of the shadows. However, its long term stability and the effects on the paper and on the ink of the chemicals contained in the coating is still largely unknown. Last but not least, the coating itself makes the support medium stiff and artificial, sometime similar to a gesso substrate. A long way from the beauty of fine arts, rag papers.
The more traditional silver-gelatin prints made in a darkroom, when archival methods are used to tone the silver halides and to wash the final print have now surpassed the century in terms of longevity. Appropriate toning is mandatory, as the silver in the emulsion is not stable as carbon and would darken in time. Nonetheless, silver-gelatin prints need to be processed in very strong chemicals in order for the image to form. Such chemicals, as the sodium thiosulfate contained in the fixer, will stain the paper over the time if not completely removed from the medium. No chemical processes are used in carbon-gelatine printing where the carbon pigments are just mechanically sprayed on the support and are trapped between the paper fibers and the final protective coating.
Carbon is known to be one of the most stable substances in Nature. Prehistoric carbon graffiti are found in caves after surviving several thousand years.
The base ink used in Carbon-Gelatin printing and the way to deploy onto paper are the result of about one and hakf year of R&D by Mantinieri. It consists of a water solution containing carbon pigments and few substances needed to keep the carbon particles in suspension. The concentrated ink is further diluted by the artist with proprietary bases, mostly containing distilled water , alcohol and pure vegetable glycerine to make several shades of gray inks. Such substances, all natural, are know to cause no harm to paper nor to the carbon pigment and are commonly used in fine art painting. The formulation of the base used to diluted the concentrated pigment carbon ink is specific to the paper support used. In fact, fine art papers are sized differently depending on the application they are made for. The tonality of the image and the dot gain change drastically with a change in formulation of the ink. Therefore, each particular paper needs a specifically formulated ink to optimize the absorption by the fibers and to minimize the dot gain. No additives are used in the solution used for making the diluted inks (like dispersant or preservatives); these inks are, in fact, freshly prepared by the artist on a weekly basis. Then, several shades of carbon ink are sprayed on the paper using a customized inkjet printer. A special computer software called 'RIP' (Raster Imaging Program), is used to print the Black and White images using these very special inks. The process depends critically on the ink-paper choise and needs to be tuned for each individual combination.
Finally, the print is washed in running water to eliminate any residual chemical present in the base ink. Only the very archival carbon pigments remain trapped inside the cotton fibers of the final print.
After few days the ink has completely dried and the print undergoes the process of gelatin coating. The final paper coating has two purposes:
a) it protects the paper and the ink from atmospheric agents
b) it enhances the contrast of the image producing deeper blacks and a 3-dimensional rendition.
It consists of a gelatine based emulsion similar to that used in the preparation of fiber based silver gelatin prints. The main difference is that in the case of Carbon-Gelatin printing the emulsion covers the (carbon) particles forming the image rather than embedding (silver halides) into them. Few more proprietary substances are added to give the desired appearance to the emulsion and to help in the coating process. They are completely natural and not chemically active. Once the gelatine coating is dried, it forms a barrier impenetrable to liquids and atmospheric chemicals protecting the paper and the carbon pigments for very long time. Gelatin based coating is commonly used in art work restoration as it is easily removed from the substrate without ruining the underlying art. In fact, immersing the print in a water bath at 40 °C is sufficient to liquefy the gelatine and fully removing it from the paper without any mechanical intervention. After the restoration, a new coating is easily reapplied whenever necessary.
The other purpose of the gelatine coating is to enhance the depth of the shadows in the image with a very pleasing and delicate shine effect. A similar look is only found in air dried fiber based silver gelatine prints and it is totally different from the plastic look of the, commercially available, glossy inkjets papers.
The coating is applied by hand by the artist using freshly prepared emulsions. The final print takes about one week to fully dry. The whole process of producing a Carbon-Gelatin print takes about ten days.