Is that a real crocodile skin handbag or could it just be cow leather made to look that way? Thanks to the technique of leather embossing, it is possible to achieve a wide range of different patterns and images, including mimicking the grain of other animal skins.
Even leather specialists can’t always determine what the original hide was before it was embossed, without detailed investigation.
Embossing involves changing or modifying the natural grain of an animal skin by pressing or rolling a new scar design. Leather experts call this ‘pressed scars’. As well as covering the entire skin surface, you can apply individual motifs.
Correcting the scar
During their lifetime animals may be wounded or suffer diseases, all of which leave their mark on their skin. Embossing will cover any scars and provide a uniform grain. This reduces waste and cuts costs. Skins that are unsuitable for processing into full-grain leather can be used as embossed leather. It’s worth noting that only about 10-20% of the hides coming from the slaughterhouse are ‘good’ to ‘very good’ quality. Embossing doesn’t lower the quality, provided that it is not covering serious damage that could affect the life of the finished product.
Corrected grain leather
In preparation for embossing leather, the grain side of the leather is first ground to obtain a uniform surface. Then a binder-based paint is applied and a uniform grain imprinted. This leather is known as ‘corrected grain’ or ‘corrected scar’. It is cheaper and has a cold, plastic-like feel. Also the breathability is significantly lower than with porous leathers.
Interestingly, grinding the grain side is prohibited on leather used in the car industry. This is to prevent using hides of too poor a standard.
The embossing process
There are two main different types of embossing: ‘blind embossing’ and ‘colour imprint’. In blind embossing the plate is heated and pressed onto the material without any colour film. In colour imprint a colour film is pushed between the leather and the press. These come in a variety of colours. Blind embossing is mainly done on plain leathers and colour imprints on pigmented smooth leathers.
Sometimes the leather has previously been embossed with foam and lining so that the final embossed pattern sits neatly and at the correct depth. Particularly strong imprints need to be further stabilised with filler material, such as papier mache or hot glue.
Embossing is done with a pressure of about 300 kilos at a temperature of 40-90°C. The leather is not moistened as it would otherwise get damaged with the heat. The embossing time, depending on the leather thickness and strength, is between 2-30 seconds.
Almost any type of leather can be embossed. However, the embossing must be adjusted according to the type of leather. The resistance of an embossing depends on the process. The higher the pressure and the temperature – and the more moisture in the leather – the more permanent is the reshaping of the fibre. But of course there are also limits to the pressure and temperature that can be applied to each leather type.
Because rolling or stamping tools are expensive – a stamper 10cm x 10cm in size can cost anywhere around £100-£120 – single motifs are therefore usually hallmarked (more on hallmarking, piping, seams, etc in our next blog). Meanwhile, it is also possible to apply motifs using lasers.