ISO 4683-1:1998
(Main)Raw sheep skins — Part 1: Descriptions of defects
Raw sheep skins — Part 1: Descriptions of defects
Peaux brutes de moutons — Partie 1: Descriptions des défauts
General Information
Standards Content (Sample)
IS0
INTERNATIONAL
4683-l
STANDARD
First edition
1998-03-01
Raw sheep skins -
Part 1:
Descriptions of defects
Peaux brutes de moutons -
Partie I: Descriptions des dkfauts
Reference number
IS0 4683-l :I 998(E)
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IS0 4683-l :1998(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for which
a technical committee has been established has the right to be represented
on that committee. International organizations, governmental and non-
governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 4683-l was prepared by Technical Committee
ISOmC 120, Leather, Subcommittee SC 1, Raw hides and skins, including
pickled pelts.
IS0 4683 consists of the following parts, under the general title Raw sheep
skins:
- Part I: Descriptions of defects
- Part 2: Designation and presentation
0 IS0 1998
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
or utilized in any form or by any means, electronic or mechanical, including photocopying and
microfilm, without permission in writing from the publisher.
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IS0 4683=1:1998(E)
INTERNATIONAL STANDARD o iso
Raw sheep skins -
Part 1:
Descriptions of defects
1 Scope
This part of IS0 4683 describes the defects which may occur on raw sheep skins
(see note I). It is applicable to fresh and cured (air dried, wet salted or dry salted)
sheep skins.
NOTE 1 Those defects which may appear only during or after tanning, without there
being any indication of their presence on the raw skins, have also been listed in this part
of IS0 4-683.
2 Defects
The defects listed in this part of IS0 4683 are divided into the following three
categories:
a) Ante-mortem defects,
b) Post-mortem defects, and
c) Preserving defects.
2.1 Ante-mortem defects
2.X 1 Abscesses; cysts
Either tearing or hardening of the dermis caused by the presence of raised lumps
on wooled sheep- skins.
2.1.2 Defects peculiar to wool-on skin
a) Fibre diameter and fibre growth irregularities that lead to fibre weakness
and breakage; and
b) Wool/hair slips (tendency towards loss of wool/hair, as a result of illness).
2.1.3 Canary yellow wool
Canary yellow wool is wool with a bright yellow unscourable stain within the wool
staple. It is caused by micro-organisms that grow in the fleece when it is damp
and warm, e.g. in wet, humid summers. The condition can cause weakening of
the wool fibres.
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IS0 4683-l :1998(E)
1
2.1.4 Dermatophilosis (lumpy wool)
The defect is visible as a crusty or scaby encrustation in the wool. It results from
the exudate that arises from DermatophiIus congolen& ( a bacterium) infection
of the dermis. It is associated with follicular distortions which give rise to the grain
defect known as white spot.
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2.1.5 Earth stains
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When laterite dust is settled on the epidermis, in large extensive patches, it gives
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rise to “ink stains” due to the presence of iron after the skins are vegetable
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tanned.
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2.1.6 Ecchymosis
Spot on the flesh side of the skin, varying from dark red to brown, caused by
sub-cutaneous bleeding, especially if the animal has been struck by a blunt object
. .
or if parts of the fleece have been roughly plucked before slaughter. This defect!
is commonly known as bruising.
2.1.7 Fire mark
Sheep skins deteriorate in quality due to fire-mark. This is a man made defect. ,.
Fire mark is generally inflicted in different parts of the body ‘with a view to cure
some ailments. In raw skin, the defect is readily seen on the flesh side and is also
prominently visible on the grain finished leather.
2.1.8 Greasy skin
. L
Skin in which the histological structure of the dermis is abnormally loose due to
I .
the penetration of grease. This state is revealed after tanning by an empty or a
hollow skin, and can give rise to an alteration in the mass/surface ratio. Delamina- ” ”
tion may also occur in the greasy skins.
2.1.9 Heat sores
Small scabs, varying from light to dark yellow, visible at the base of the wool fibres
and on the flesh side. They give rise to a defect in the grain, often called “mite
sores”.
2
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IS0 46839 1:1998(E)
2.1 .lO Hyper-pigmentation
Black hair female sheep skins are found to be affected on the grain on both sides
of the back-bone (particularly in the butt area) due to hyper-pigmentation. Hair
loosening may be noted in the affected areas. Physical properties of the leather
in the affected area are poor associated with grain erosion and sometimes
resulting in perforation.
2.1.11 Marks on the fleece
Damage caused by paint, tar, wax crayon, aniline dyes, which devalues the wool,
leading even to matting of the hair.
2.1.12 Moire
Long wrinkles in the direction of the spine, running parallel and symmetrical in
relation to the spine. (They are a sign of a lack of density in the dermis and,
depending on the finishing, often remain very clearly on the grain or flesh or on
the wool).
2.1.13 Pin hole
When two or more wool follicles merge or kemp emerges from the follicles, it is
known as pin holes in many countries. This is a genetic trait related to fine wool
breed. This is invisible in raw sheep skins (also refer to 2.1.15.5 for pin holes of
Ectoparasite origin).
2.1.14 Poor wool crimp definition
A wool staple is a natural grouping of wool fibres into discrete bundles. Crimp is
the bold waves. folds or corrugations of wool fibres within the wool staple. Poor
wool crimp definition is the loss of these corrugations and the straightening of the
wool fibre to more resemble hair. This condition has been associated with age
and nutritional deficiencies. Poor crimp definition can lead to increased felting of
the wool during wet processing of wool-on sheepskins.
2.1 .I5 Problem arising from plant sources
2.1.15.1 Bushy or seedy skin
Skin with the dermis puncxred by thorns or seeds which. when imcianted, make
a small hole or become embedded obiiqueiy in the thickness cf the skin and
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IS0 4683-l :1998(E)
which, in spite of the perforation, are difficult to remove during the process of
transforming the skin into leather.
2.1 .I 5.2 Burr
Prickles from certain plants and grasses may cause defect in sheep skins. These
penetrated burr stick to the skin even after finishing into leather.
Thistle-laden skin
2.1 .I 5.3
Skin with the fleece laden with thorny plant debris which mats together the fibres
of wool.
2.1.16 Rib marks
Defects of genetic origin caused by already perceptible folds on the skins of
certain lambs leading to persistant marks, formed in long parallel furrows, at right
angles to the back-bone. Rib marks are of two types, Blind rib and Lap rib. While
blind rib is visible on the skins only and can not be identified on wooled sheep
skins, lap rib is more severe form of skin defect. Lap ribs can be seen in the raw
wooled skins as patterns of wool growth. It is most obviously reflected in the
merino stock.
2.1.17 Skins infested with Ectoparasites
2.1 .17.1 Bobble
This is considered to be a viral disease prevalent in sheep skins. In raw skin, the
lesions are generally visible on the flesh side as round spots but after unhairing
they become more prominent on the grain side. Bobble lesions have per-
manent stains on both chrome and vegetable tanned leathers and render them
unsuitable for quality leathers.
2.1.17.2 Demodex
Skins on which it is possible to see, on the flesh side, nodules of varying size
(several mm to more than 5 cm). The small nodules are not altered by beamhouse
operations and show up on the tanned skin by a hardening of the tissue. On the
other hand, if they measure more than 1 cm,they can form a pit by splitting th%e
grain, or even a hole. This defect is caused by Demodectice mange (Follicular
mange) mites. These mites may appear in:
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nodular forms,
9
. .
squamous forms, and
9
. . .
III) acute forms.
2.1.17.3 By lice
Because of the irritation caused by the biting or sucking type of lice, the animals
scratch the affected parts of the body which leads to wounds and bruises. Lice
species belonging to the genera Linognathus are found in sheep skins. Sheep
skins infested with lice (Linognathus ovinus, Order Anoplura
...
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