With sublimation, the image is diffused by thermal sublimation in the thin layers of polyester varnish previously deposited on rigid supports of a very high flatness. This is one of the major differences with other techniques for transferring or laminating paper prints on metal or plexiglass plates. Here the image « is an integral part of the support » and nothing comes between the work and the eye, the polyester varnish offering a neutral protection of the image, absolutely imperceptible. What’s more, this transparent protection is resistant to fingerprints, scratches, ageing, temperature fluctuations and contact with even the most corrosive products. It is also resistant to direct flame exposure!
This technique therefore requires the use of specific supports prepared in advance: aluminium plates covered with a first layer of pure white substrate, then seven layers of perfectly transparent polyester varnish. The adhesion of these layers to the substrate is total. The image is then written on these plates by contact and hot pressing at more than 200°C of a transfer print on a special paper, with sublimation inks, printers and a RIP* (Raster Image Processor, a computer driver allowing the physical printing of digital image files.) calibrated precisely for this use. To guarantee maximum quality, PIX Fulfillment uses ChromaLuxe plates, the only ones on the market today that provide very high contrast and a wide range of colours. The purity of their white background is exceptional and rivals that of the most neutral papers.
The printing quality must be perfect, as must the uniformity of hot pressing, which is carried out by very large presses. During the passage at high temperature, the inks deposited on the paper pass directly from the solid state (powder) to the gaseous state: it is sublimation. The tiny coloured bubbles thus generated are then trapped in the polyester molecules, which have opened under the effect of heat and gradually close again as they polymerize when they return to the environment. In the end, the coloured pigments are encapsulated in a completely waterproof way in extremely resistant transparent varnish beads.
The reproduction requirements of the photographic image are excessively high, and sometimes contradictory:
Moreover, this printing technique is sufficient in itself for the exhibition of the works. Apart from an enhancement by the adoption of an inset, flush frame or an American box (options available on order), the works produced do not require any particular protection (film, plexiglass or glass) to be exhibited, even outdoors. Because the sublimation process also guarantees – and this is its other superiority – the great insensitivity of the supports to mechanical, thermal and chemical aggression. The ageing of the varnish has practically no effect on the image rendering, whose colorimetry remains very stable over time: no long-term drift, no dulling of colors.
With sublimation, the eye is in direct contact with the reproduced work, now inseparable from this high-end medium that magnifies it, which makes it a work of art in its own right.
Chromaluxe, currently the only manufacturer of quality plates, is located in the United States and has been using this technique for several years. Two American research laboratories have conducted environmental tests on photographic prints made with these plates and have clearly established that they are the most durable photographic media on the market.
The first tests were to reproduce the effects of a mixture of incandescent lighting and indirect daylight, and to detect a significant attenuation of colours. The plates were compared to the three best photographic papers available (archival quality): the results show that sublimation reproductions last twice as long as the first two paper references and four times longer than the third.
The second independent laboratory reproduced the effects of fluorescent lighting in an open office environment (no windows). In this test, the plates resisted color attenuation 1.7 times longer than the best paper reference. However, these are papers that are themselves given for a stability of more than a hundred years!
Moreover, our own experience shows no alteration of the supports or colours after a continuous exposure of 3 years outdoors, without any particular protection (plates exposed directly to the bad weather).
The sublimation process imposes high requirements throughout the production line, which remains entirely manual. The prints are therefore made in a traditional way, in accordance with a rigorous procedure that guarantees the accuracy and perfect reproducibility of the result:
The production chain is subject to regular controls (consistency of definition characteristics, contrast, colorimetry).
Important note : In order to maximize the quality of the prints and avoid any inconvenience to our customers, our ordering process prohibits the choice of a format that would not match the definition of the files provided. Since our working resolution is 300 dpi, it is advisable, to order a print size of 30 x 40 cm, for example, to provide a file that is at least 30 x 40 cm at 300 dpi (i.e. with 3602 x 4783 pixels). Such files can be very large and will take several minutes to load on our site, which is not a problem.
