<s>
Hatching	B-Application
(	O
)	O
is	O
an	O
artistic	O
technique	O
used	O
to	O
create	O
tonal	O
or	O
shading	B-General_Concept
effects	O
by	O
drawing	O
(	O
or	O
painting	O
or	O
scribing	O
)	O
closely	O
spaced	O
parallel	O
lines	O
.	O
</s>
<s>
When	O
lines	O
are	O
placed	O
at	O
an	O
angle	O
to	O
one	O
another	O
,	O
it	O
is	O
called	O
cross-hatching	B-Application
.	O
</s>
<s>
Hatching	B-Application
is	O
also	O
sometimes	O
used	O
to	O
encode	O
colours	O
in	O
monochromatic	O
representations	O
of	O
colour	O
images	O
,	O
particularly	O
in	O
heraldry	O
.	O
</s>
<s>
Hatching	B-Application
is	O
especially	O
important	O
in	O
essentially	O
linear	O
media	O
,	O
such	O
as	O
drawing	O
,	O
and	O
many	O
forms	O
of	O
printmaking	O
,	O
such	O
as	O
engraving	B-Application
,	O
etching	B-Algorithm
and	O
woodcut	O
.	O
</s>
<s>
In	O
Western	O
art	O
,	O
hatching	B-Application
originated	O
in	O
the	O
Middle	O
Ages	O
,	O
and	O
developed	O
further	O
into	O
cross-hatching	B-Application
,	O
especially	O
in	O
the	O
old	O
master	O
prints	O
of	O
the	O
fifteenth	O
century	O
.	O
</s>
<s>
Master	O
ES	O
and	O
Martin	O
Schongauer	O
in	O
engraving	B-Application
and	O
Erhard	O
Reuwich	O
and	O
Michael	O
Wolgemut	O
in	O
woodcut	O
were	O
pioneers	O
of	O
both	O
techniques	O
,	O
and	O
Albrecht	O
Dürer	O
in	O
particular	O
perfected	O
the	O
technique	O
of	O
crosshatching	B-Application
in	O
both	O
media	O
.	O
</s>
<s>
Artists	O
use	O
the	O
technique	O
,	O
varying	O
the	O
length	O
,	O
angle	O
,	O
closeness	O
and	O
other	O
qualities	O
of	O
the	O
lines	O
,	O
most	O
commonly	O
in	O
drawing	O
,	O
linear	O
painting	O
and	O
engraving	B-Application
.	O
</s>
<s>
Hatching	B-Application
lines	O
should	O
always	O
follow	O
(	O
i.e.	O
</s>
<s>
An	O
area	O
of	O
shading	B-General_Concept
next	O
to	O
another	O
area	O
which	O
has	O
lines	O
going	O
in	O
another	O
direction	O
is	O
often	O
used	O
to	O
create	O
contrast	O
.	O
</s>
<s>
Crosshatching	B-Application
is	O
the	O
technique	O
of	O
using	O
line	O
to	O
shade	O
and	O
create	O
value	O
.	O
</s>
<s>
In	O
technical	B-Application
drawing	I-Application
,	O
the	O
section	O
lining	O
may	O
indicate	O
the	O
material	O
of	O
a	O
component	O
part	O
of	O
an	O
assembly	O
.	O
</s>
<s>
Many	O
hatching	B-Application
patterns	O
have	O
been	O
standardized	O
by	O
the	O
American	O
National	O
Standards	O
Institute	O
(	O
ANSI	O
)	O
and	O
the	O
International	O
Standards	O
Organization	O
(	O
ISO	O
)	O
,	O
though	O
there	O
are	O
many	O
other	O
predefined	O
patterns	O
that	O
may	O
be	O
used	O
.	O
</s>
<s>
Thus	O
,	O
the	O
hatching	B-Application
pattern	O
of	O
steel	O
varies	O
from	O
that	O
of	O
aluminum	O
,	O
copper	O
,	O
etc	O
.	O
</s>
