Buying tips for garment leathers
Leather is a unique natural product with many highly desirable characteristics. However, it is important to apply an awareness and understanding of the different types, properties and variations in the raw materials to ensure satisfaction with the end product.
1. Leather Selection
Raw material – selecting leather that is fit for the purpose is crucial. For example; cowhide is not the most appropriate leather to make a lightweight ladies garment. If you need a strong, lightweight leather then a large mature sheepskin may be weak when cut down to a substance of 0.7mm. Seasonal variations and animal breed will affect quality and size, and potentially cutting values and costs. There are no hard and fast rules but a basic understanding of the types of raw material and their inherent characteristics is a good starting point.
Leather types – different finishes are available and once again the end use needs to be uppermost in the mind. Pigmented and semi aniline leathers will have better fastness properties than anilines, nubucks or suedes. However, pigmented leathers are more likely to have a less natural appearance. Aniline leathers and oily nubucks have a tendency to soil easily and are more difficult to clean. Colour rub off problems may occur with waxy, greasy leathers and nubucks.
Leather quality – the old adage applies here ‘you get what you pay for’. It may be better to pay more for the leather than push the margins. If price is squeezed on a garment the most likely place for savings is the leather and this can mean different qualities of raw material from that sampled!
Sampling – make sure that the quality of the leather is clearly agreed at an early stage, specifying what is and is not acceptable on a finished garment. If you pay for top quality nappa that is what you expect to receive. It is advisable to keep a good-sized sample of the leather and fingerprint test for reference.
Quality – when buying or specifying leather, you need to be aware that leather can either be graded or bought as a mixed selection. If the leather is graded then you can set the standards and agree which grades should be used for each garment panel.
Variation – leather is a natural product and depending on the type of leather selected a degree of variation must be expected. This variation can be minimised and controlled through efficient process controls during manufacture. Once again be aware that some raw material may be subject to seasonal variations in quality and size. Clearly set the type of variations you are prepared to accept and check each delivery against samples prior to despatch to stores.
2. Performance Specification
Standards – understand and set realistic standards for leathers to ensure that the terms of reference to your supplier are clear. Rejecting a batch of garments because of weakness, fastness or water spotting a month before Christmas can cause stress!
Test – verify the performance of your leathers before they are made up and then re check each individual batch. Essential tests include: strength, fastness, dry cleanability and flexing on pigmented leathers.
Restricted substances– these are increasingly important to the consumer as awareness grows. A regular check may be prudent if you are uncertain of the processes used by your suppliers. Typical tests for first time suppliers would be PCP, Azo, Chrome VI and Formaldehyde.
Aesthetics – these are not as difficult to measure as they may seem. Touch, thickness, softness, colour, brightness and smell can all be measured scientifically against specified standards.
Bloom or Spue – this is a white substance that appears on leathers. It is catalysed by temperature and humidity changes and is often evident on garments or leathers after shipping. This is a processing problem due to either natural fats or free fatty acids as a result of an inappropriate combination of processing chemicals or even salt migration.
Shipping – many problems can occur during shipping. Leathers will crease and finishes may stick together in humid conditions. Therefore it is important to specify how the leather or garments should be packed during transportation.
Eurofins | BLC Leather Technology Centre Ltd can help you to improve your knowledge and overall awareness of factors relating to leather with their one day leather courses ‘Understanding Leather’. Eurofins | BLC can also work with you to set standards, develop specifications and test against specifications. For further details visit www.blcleathertech.com.
Leather which has been dyed but has not received a pigmented coating, a bit like staining wood rather than painting it.
Aniline leather which has received a surface coating containing a small amount of pigment in the base coat. The surface coating helps impart greater stain resistance.
Aniline leather finished by lightly buffing or sanding the grain surface to produce a velvety nap. Nubuck has a much finer nap than suede because the grain layer has a tight fibre.
Oily nubuck – see pull-up leather.
Leather which has received a surface coating containing pigments. This surface coating can impart greater wear resistance, water resistance and protection from staining.
Leather designed to lighten in colour when stretched, producing a worn-in effect with time.
The result of splitting leather into layers. A split has not natural grain surface and may be buffed to produced suede or have an artificial grain applied to produce a finished split.
Leather produced by buffing or sanding a split to produce a velvety finish or nap. The nap is not as fine as nubuck because the fibre structure is looser without the grain layer.
Waxy, greasy leather – see pull-up leather.