As one of fashion’s true allies, leather knows no bounds when it comes to assisting creativity. Although already greatly appreciated for its texture and appearance, leather develops other charms when it is enhanced with techniques that transform its surface and its hold. Here are some of the techniques used to delight us, fascinate us and even mislead us.
An ancestral printing technique used on various media, screen printing is ideal for leather. Because the ink is applied in solid blocks, the power of the colour is unbeatable. The results are of the highest quality, but screen-printing is a long and complex process, as before the support material can be printed, the textile screen that bears the pattern first has to be made. A light-sensitive gelatinous substance made from silver salts is spread over a canvas, which has been stretched over a frame. A transparent film is placed under this frame, bearing the original design in black. All of the above is placed on a sheet of glass under which are located UV lamps. A vacuum is created to bring all the parts firmly together and then the lamps are switched on. The light emitted through the transparent film sets the gelatine on the fabric of the screen except where the shadow of the pattern has blocked the light. Once it has been rinsed with a hose, the image appears on the fabric like a stencil. The next stage is the printing itself. The textile screen is placed on the leather and a layer of ink is spread with a spatula over the entire design. The ink soaks through the textile where it has not been printed, and coats the leather, reproducing the pattern. If the design requires a number of colours, a screen is made for each colour and each colour will be applied separately to the leather. The biggest difficulty is finding the right ink which will bond to the leather and last. Leather is a living material that moves, expands and contracts. Of course the technique is more successful on uncoated rather than coated leathers. To overcome this, the finish can be added after the screen printing, which will also protect the print. As each design is produced on each skin individually, it is inevitably an expensive process. But the result is incomparable aesthetically and is more resistant to rubbing and natural light. The procedure is idea for limited editions of high-end products.
Although similar to screen-printing on smooth leather, the technique on hair-on leathers differs due to the type of ink used. These inks colour the hair by oxidation and do not all produce the same output nor impose the same constraints. Certain techniques require the hides to be immersed in a setting solution that will encourage the oxidation of the hair. Others, like the claret colour, are even more difficult to set and there is a risk of the colour bleeding. For this reason, the skins are often drummed with sawdust after they have been coloured to absorb the excess ink. The drying time is also longer. And the weather conditions during the drying period can also extend its duration: when the weather is dry, the skins will dry faster but the hair will be less deeply impregnated with the colour. So many parameters, which mean that each result is even more unique.
Screen-printed hair-on vachetta leather by Manutrans
Digital printing is another way of decorating leather by placing an image on it. Using the inkjet technique, it allows direct reproduction of a digitalised visual image, on all types of skins without any prior treatment being required, and offers incredible precision and fineness. In comparison with other methods, digital printing offers great advantages. The ink is absorbed by the material and does not form a film on the surface. The print will therefore last longer and the texture of the leather is not affected. Nor is its fragrance, thanks to the quality of the inks that are used. Some can be used on patent finishes. Each skin is printed individually making it possible to personalise each item, and the pattern can be repeated or appear just once, even on large format skins. And we don’t set a minimum quantity. In comparison with transfers, a rival technique for decorating skins, inkjet printing does not damage the leather through the use of intensive heating that stiffens it considerably. For tanners with dormant stock, digital printing is a good way of transforming these skins and making them more attractive.
All-over digital printing by Conceria Vignola
Digitally printed bovine flesh split by Ge-Fin Leather
Digital printing on lamb leather by Naturca by Aysen Butik
It is also possible to print on leather by transferring onto the leather a design printed on a film, under specific conditions of heat and pressure using plates or cylinders. Only the patterns stick to the leather. Consequently it is not completely covered and the texture and grain remain in the background. It is even possible to superimpose a second transfer on the first to add an additional effect, such as metallisation. A customized design is possible, but requires a certain investment and a large production run. “To improve the adhesion of the transfer, we can buff the leather slightly or treat the surface with a specific chemical product,” explains a manager from Curtidos Bassols. However, to apply a multicolour design, the entire film must be applied to the leather which then will cover it completely. Furthermore, the high temperature needed for the procedure (between 120° and 150°C) draws out the humidity in the leather and tends to stiffen it. But this is a price worth paying for second choice skins that get a new lease of life.
A number of films are superimposed, one with a floral pattern,
the other leaving a pattern of scales on the surface. Emelda Tannery
Two layers of film, one providing the colour,
the other drawing a mesh on the surface. Curtidos Bassols
Combining leather with a second material that partially covers the surface is another of the decorative techniques for leather. For example, laminating leather with an openwork fabric, such as lace or net, creates a decoration on the surface of the leather without damaging it. A number of lamination techniques are used to achieve this result. The first involves pasting the textile using spray glue. “We produce and use aqueous glues to our own formulasn which differ according to the type of textile and the thickness of the leather”, explains Fatima Valentin, the commercial director of Eureka, a company that has been laminating leather since 1999. The production is continuous, using special pasting machines. “We can alter certain parameters according to the desired result, modifying the amount of glue spread on the material (certain materials absorb more glue than others), the pressure, the temperature, the drying time, to vary the density of the gluing,” says Julien Château of Château, another lamination specialist. In certain cases, both materials – the leather and the textile – can be coated in glue; but in the case here with an openwork textile, only the underside of the textile is glued, so as not to cover all the grain of the leather with the adhesive. “The glue cross-links, which means that the chemical reaction that produces the binding continues for a moment after the bonding itself, strengthening the bond between the two materials,” explains Fatima Valentin, before going on to say that “the hides must be properly positioned before being glued, they have to be stretched taut so that there are no folds.” Sometimes the textile is pre-coated with glue that is then reactivated by hot-pressing. This is known as hot-melt gluing. The second technique uses powdered glue that is spread on the surface and heat-activated. The third technique, known as singeing/hot-melt does not require adhesive but can only be performed using synthetic textiles. “A flame is applied to the synthetic material, which melts superficially. The leather is then applied, so that it bonds with the surface in fusion,” described Julien Château. “We can laminate all types of skins: lamb, goat, cow side leather, crocodile. We have even just done it with salmon leather. There are many applications for this, in leathergoods, footwear and clothing,” concludes Fatima Valentin.
Lamb leather decorated by lamination with a mohair and silk lace. Eureka
Lace bonded onto suede lamb by Tari
Luxury can afford to take its time, and it can be considered that the lengthy turnaround required for leather marquetry work is irrefutable proof of the excellence of the technique, as illustrated by this camouflage, by Industrie Pellami, intricately created by hand. “The pieces are cut out by laser in very specific shapes. Each one of them is glued onto the background material according to a pre-planned design, like a jigsaw. This is very high quality work!” declares, not a little proudly, the manager of this Italian tannery.
Camouflage recreated by Industrie Pellami
Needle-punching is a binding method that is usually used to combine or strengthen two non-woven textiles. Here, very fine needles pierce the non-woven textile placed against the flesh side of the leather then the leather itself, dragging with it the textile fibres that design a pattern on the surface. In general, the non-woven textile is made from wool or acrylic. It can be bound with the leather by a prior lamination. “This technique is mainly possible with lamb leather, as it is thin enough for it,” explains our correspondent from the Pelicon tannery. A veritable technical performance, for clothing or leather goods, and guaranteed to cause a stir!
Needle-punching on gold metallic lamb leather by Pelicon
Needle-punching by Bopell
Here the pattern is in the negative, designed by the gaps left by the needle-punching Usak Cevahir Deri
PREMIERE VISION LEATHER HALL 3