Warping (ourdissage) is the operation which
consists of preparing the warp threads before assembly on the loom. This
preparation is done according to the number of lames and the length of
the tapestry to be installed on the loom.
Each lame of warp, or portion of 40 cm of threads,
is warped individually. These groups of threads corresponding to the lames
are called crenilles.
The length of the crenilles corresponds to that
of the tapestry to be made by adding the loss of warp called saut, that
is to say approximately 1,20 m (possibly a little more if it is a bar loom – métier
à barre – or capstan).
The number of threads contained in each crenille
varies depending on the density of the warp, that is to say the number of portées
per lame.
The warping (ourdissage) is done from five
wooden dowels allowing, on one hand, to
establish the length of the crenille, and on the other hand, to make crosses
(encroix or enverjures or croisures), markers of threads
in preparation for the arrangement on the loom. *
*The cross (encroix) is the crossing of two layers
of even and odd threads, between two wooden dowels i.e. sometimes a thread
above then a thread below, sometimes six threads above then six threads below
each dowel.
The arrangement of these five dowels is done according
to two kinds of crosses (encroix) A and B as follows :

A – on one hand two dowels 1 and 2.
B – on the other hand three dowels 3, 4 and 5.