The wool yarns were first scoured with 0.5 % nonionic
detergent in the bath with L:G (liquor to good ratio) of 40:1 for
30 min at 50 oC. The scoured wool were then mordanted with
20 % o.w.f. AlK(SO4)2 at L:G of 40:1. Formic acid was used
for adjusting the pH 5. The mordanting started at 40 oC and
rose to boil over 20 min and remained at the boil for 1 h. The
dye solution were prepared 24 h before dyeing by adding the
flowers of Marigold to water (Marigold:water=10:1). The
dyeing bath prepared by adding 50 % ow.f of dye solution,
pH of 5 with formic acid and L:G of 40:1. Dyeing was
started at 40 oC and temperature raised to 85 oC over 20 min
and held for 1 hour. Treatment with ammonia solution was
carried out after dividing the dyed samples into four parts.
One part was retained for reference and the others were each
treated with ammonia solution (1 %, 3 % and 5 % w/w) at