Difference between revisions of "Natural markings on leather"

Revision as of 07:55, 12 September 2019

Natural markings on leather

Natural markings on an animal's skin, depending their severity and extent, can affect the usability of the rawhide for a specific type of leather.

The extent of damage dictates how much of the skin is usable during cutting, leading to higher levels of wastage per skin. There are two categories of damage: postural injuries incurred during the animal's lifetime and damage after slaughter.

Below are some examples, which are typical in practice and make the leather partially unusable and cause higher waste. Many of the skin damages are not detectable on the rawhide. They only become apparent after the first processing stages in the tannery.

The different types of damage cannot always be clearly defined. A barbed wire scratch may look like a pitchfork injury and what looks like a tick bite can have various causes.

Statistics indicate that approximately only 5% of all rawhides are free of damage and suitable for processing as aniline leather. Because the natural grain remains visible on aniline leather, the skins must be flawless.

Leather with minor damage is sanded and evened out with fillers, then dyed and embossed. Alternatively, for dyeing and stamping, foils are glued onto the leather surface. In this way, the skin may still be used for cutting larger sections. As long as the coated damage is not too large and the durability of the processing is long-lasting, such leather is of good quality within its price range. However, severely damaged leather is often processed without meeting the expected longevity. This tends to occur in the lower price segment.

Dung marks - Manure burns

Dung marks are the result of faeces sticking to the skin for long periods. If not removed quickly, it can cause burns. Also, when the animal sweats beneath the dung marks, the skin pores dilate. Provided the dung marks are not too severe, the skin is still usable.

Manure burns zoomed - Pore enlargement is clearly visible (click on last image)

Pitchfork injuries

Pitchfork injuries, as the term suggests, are caused by prodding the animals with sharp objects. They are also known as goad marks. Where such injuries have occurred frequently and healed badly, the leather is unusable.

Warts

Cattle get warts, just like humans. During the tanning process, leather goes through so many machines that warts often tear. Even without tearing, warts deteriorate the skin quality.

Barbed wire scars and scratches

In addition to barbed wire scars, animals can incur a whole range of scars and scratches caused by contact with sharp objects, such as thorns or branches. The number of scars, their length, width and spread across the skin are all factors that determine the extent of the use of such leather.

Typical barbed wire scars.

Scar from a barbed wire injury on the grain side and flesh side.

Horn scratches and blows

Injuries from horns occur during bullfights and leave significant scars.

Surgical scar

Animals can also have surgical scars which are visible on the leather.

Neck wrinkles - Creases

Neck wrinkles and creases are a normal phenomenon and do not affect the value of the leather. They occur in cattle in the neck and abdomen, where the connective fibres are longer. Neck wrinkles naturally occur in a hide as a result of the neck stretching and contracting. The grain pattern is stronger in this area.

When cutting the leather, it is essential to make sure that the graining on the finished object is symmetrical. However, where there is varied graining in an object, this usually an intentional effect.

Typical neck wrinkles in cattle.

Insect bites

Tick bites and stings of other insects appear as small surface damages on the skin.

Tick bites and other insect damages.

Fire brand - hot brand

Hot branding is a technique for marking cattle and other farm animals so as to identify the owner. Conventional methods are hot branding, freeze branding, earmarking, tattooing or the implantation of microchips. Hot and freeze branding are very painful for animals and therefore not universally allowed.

In the USA, about 45% of all cattle were hot branded in 2011. In 2017 it was only 26%. The trend to mark cattle with hod branding is declining in wealthier countries.

Branding iron (German Leather Museum at Offenbach).

Brand marks are burned with branding irons into the skin.

With branding iron marked cattle in Brazil.

Branding in a cowhide and on finished smooth leather.

Visible scars of branding in the back of furniture are not a sign good quality.

Branding on smooth leather of a cow with and without finish.

On pigmented, sanded and embossed leather (corrected grain), the branding is invisible. When heating the leather from behind, the branding can be made visible with a thermal imaging camera.

Warble fly

Warble fly are parasitic on cattle and deer. The fly lays eggs on the forelegs of cattle and deer. The eggs hatch within a week and penetrate the skin, where they migrate throughout the connective tissues. After a few months, the larvae travel back to the skin surface and cause swellings. When breaking through the skin, the fly leaves holes in the skin and visible scars remain. In South America exist variants that can infect humans.

Warble fly and warble made.

Warble bump on the back of a bovine. - Warble made under the skin of a deer.

Grain side damage of the warble fly in deer skin.

And same on flesh side.

Deer fur with damages caused by the warble fly.

Trichophyton verrucosum – cattle ringworm fungus

Trichophyton verrucosum or cattle ringworm fungus is a fungal disease of the animal skin and is caused by the fungus Trichophyton verrucosum. The cattle ringworm fungus disease is common in cattle. Mostly young animals are affected by the disease in the first two years, but also older dairy cows can become infected and also humans and other animal species can get this desease. The sick animals get partial hair loss. The affected areas usually have rounded shapes. The skin becomes barky in these areas and get lighter and greyish. The spread begins around the eyes and then spreads further. In adult dairy cows, the fungus infects less the head, but more the rest of the body. The excretion of toxins of the fungus is the cause. The lichen is spread by flies, mites or lice. dauerhaft verändert.

'The disease is easily recognizable. The hair falls out (photos www.leder-fiedler.de).

The disease heals spontaneously after one to three months. The skin changes are then often recognizable in the ready tanned leather. On aniline leather that has no finish layer on top, such stains remain undesirable visible. In these areas, the scarring of the wounds has permanently changed the skin structure.

In aniline leather, the infected areas remain visible. The skin structure is permanently changed and scarred by the lichen. (photos www.leder-fiedler.de).

Damages when skinning in the slaughterhouse

When skinning in the slaughterhouse the skin can get damaged. Incorrect cutting can reduce the yield of surface. In slaughterhouses the animals are often skinned by machines. The strong force in this process, may bust the grain pattern .

Damage when cutting and busted scar.

Other reasons for skin damage

• Conservation damage damages caused by inadequate conservation after skinning (fouling by bacteria influence or salt stains).
• Skin parasites like mites and lice damage the skin and affect the quality of leather.
• Skin fungi (skin lichens) damage the skin and thus the end product leather.

Are skin damages a deficiency?

Customers want flawless goods. Wrinkles, scars or leather grain texture differences are perceived as imperfections. But many surface differences belong to the naturalness of the leather. A well overgrown scar is often more stable than the surrounding leather. A wrinkle in the leather is as natural as in your elbow or in the palm of your hand. The natural leather grain pattern varies in the skin surface. Any leather item with an absolutely uniform leather grain texture and colour has usually been finished (pigmented) and embossed. Such leather is colder, firmer and less natural than a leather with differences in the grain texture.

As long as a leather is stable and the differences of the offered leather qualities have been well explained, it is good service. Not every skin defect can be excused that way, but it's honest information for the customer.

Additional information

• Leather cutting
• Leather cutting waste
• Leather defect caused by the tannery
• Leather damages

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