2.2.5. Dyeing the polycotton blend
The polyester component of the poly/cotton blendwas first dyed
with disperse dye using the procedure recounted in Section 2.2.1
(Fig. 5). At the end of dyeing, the sample was subjected to either
the reduction clear procedure described in Section 2.2.1 (Fig. 2) or
to the bead wash-off process described in Section 2.2.3 (Fig. 8). At
the end of either the reduction clearing process or the bead washoff
process, the dyeing was then dyed using reactive dye as
recounted in Section 2.2.2 (Fig. 6). At the end of dyeing, the sample
was subjected to either the conventional wash-off process
described in Section 2.2.2 (Fig. 7) or to the bead wash-off process
described in Section 2.2.4 (Fig. 9). The washed-off polycotton
sample was allowed to dry in the open air.
2.3. Colour measurement
The CIE colorimetric co-ordinates and colour strength (fk values)
for each dyeing were calculated from the reflectance values at the
appropriate lmax, measured using a Datacolor Spectroflash 600
spectrophotometer under illuminant D65, employing a 10 standard
observer with UV component included and specular component
excluded. The samples were folded so as to realise four thicknesses
and the average of four measurements was taken for each sample.
2.4. Fastness determination
The fastness of the dyed samples to the ISO CO6/C2S (60 C) [12]
wash test was determined.
2.5. Photography
Photographs of glass sample bottles containing wash-off liquors
and beads were recorded using a Canon EOS 450D digital camera.