ve slightly acid properties; or
where the affinity between the two bodies (colouring matter and (p. 077)
mordant) is too great. This method can be carried out in, for instance,
dyeing a cochineal scarlet with tin crystals, a yellow from fustic and
alum, a black from logwood and copperas and bluestone, a red from
madder and bichrome, and the dyeing of the Alizarine colours by the
use of chrome fluoride, etc.

The shades obtained are usually not so deep as those got by the
mordanting and dyeing process, but are frequently nearly so. In some
cases, as in dyeing with fustic or logwood, it gives rather brighter
colours, due to the fact that the tanning matters present in the
dye-stuffs is not fixed on the wool, as is the case with the
mordanting method, but is retained in the dye-bath. For dyeing with
logwood and copperas or bluestone the process is not a good one, as it
does not give as full shades as by the ordinary process. For dyeing
with the Alizarine colours, using chrome fluoride as the mordant, it
can be applied with fair success. There are advantages in the saving
of time and labour and in the amount of steam required, all of which
are important items in dyeing.

It is rather troublesome to match off by this process, but it can be
done. For light shades the process will be found very useful, as these
cost less than by any other process. The dye-baths may be retained for
future use, although in process of time they become too dirty for use,
when they must be thrown away.

#Level Dyeing.#--The first condition for successful dyeing is that the
fibres to be treated are absolutely clean. A careful washing is not
enough for this purpose. Cleanliness is undoubtedly the condition
which the fibre must possess to enable the dye to hold on and not to
come off the fibre, this latter causes a loss of dye-stuff, soils the
whites, and gives rise to trouble between the dyer and finisher; it is
also the condition for making the dye go on the wool evenly. The (p. 078)
washing must be done at the boil, so that the fibre is well wetted
out and all the air bubbles adhering to it are driven out. But this is
not enough; it must be accompanied by a scouring operation, not only
in the case of fibres of which the dyer does not know whether they
have been scoured, but also when they have already been scoured and
bleached. The kind of scouring that the fibres receive in this case
need only be of a comparatively light character, but it