It is about basic terminologies used in dyeing

1. FUNDAMENTALS:BASIC TERMINOLOGIES
USED IN DYEING
BY
B. Venkatesh
Asst. Professor,
Dept. of Textile Technology
VFSTR University

2. • DYE AFFINITY
• Attraction of the dye to the fibre or the tendency of the dye to go on the fibre on its
own without any external influence of heat or chemicals
• EXHAUSTING AGENTS
• which help in transferring the dye molecules inside the fibre or fabric structure
• % SHADE
• Example: 4Kgs of dye is taken for dyeing of 100 Kgs of material, it is said to be
dyed with 4% Shade.
• It can be easily calculated as,
• % Shade = (Wt of dye taken for dyeing / Wt of material) X 100
= (4kgs / 100Kgs) X 100
= 4%

3. • M.L.R.
• Example: When 100 Kg of material is dyed by using 1000 litres of Liquor
(chemicals + water), the MLR is 1:10
• RETARDING OR LEVELLING AGENTS
• Dyeing assistants are added in the dye bath which gets combined with the dye to
form a loose complex.
• It cannot enter the fibre or fabric structure.
• However, this complex has to be broken subsequently.
• Generally by raising the temperature so that the dye is again made available, but
gradually for the dyeing process.
• These assistants slow down the rate of dyeing and help to produce level dyeing
results; they are called retarding agents or levelling agents.

4. • SATURATION DYEING
• If we go on increasing the % Shade of dyeing at certain depth,
the fibre will get saturated with the dye
• There will be no further increase in the depth, while the excess
dye remains in the dye bath

5. • RATE OF DYEING
• It is the amount of dye transferring into the material per unit
time.
• APPARENT DEPTH
• This is the actual depth (or shade) which you get after
completing the dyeing process.
• ON-TONE DYEING
• When the tone of the fabric is not changing with time only depth
increases

6. • % EXHAUSTION
• The dye uptake of the fibre during dyeing is expressed in terms
of % Exhaustion of the dye bath.
• % of the amount of dye goes into the fibre during dyeing from
the initial amount of dye taken.
• Thus if a dyebath contains ‘x gm/ltr’ of the dye before dyeing
and ‘y gm/ltr’ at the end of dyeing,
• % Exhaustion = (x – y / x) X 100
• Example: if 2 Kgs of dye is taken for dyeing and only 1 kg of
dye actually transferred onto the fibre while the remaining
1Kg is left behind in the dye bath than it is said to have
attained 50% Exhaustion.

7. • % EXPRESSION OR % WET PICK-UP
• It is the amount of liquor in gms carried by per 100gms of fabric after
passing through the padding mangle, which is expressed as a percentage.
• Example: 1 Kg of fabric is padded on a mangle and after passing
through the mangle if the weight of the fabric rises to 1.7 Kg.
0.7 Kg of liquor is than expressed as % to the initial weight of the
fabric
• % Expression = {(Final Wt of Fabric – Initial Wt of Fabric) /
Initial Wt of Fabric} X 100
= (1.7 Kg – 1 Kg / 1) X 100
= 0.7 X 100
= 70 %

8. • % OWM (On Weight of Material)
• The amount of chemicals in gms to be used per 100 gm of material is
called % OWM.
• Example, for 5% OWM Na2CO3, 5gms of Na2CO3 is to be used per
100gm of material
• GPL (Grams per Litre)
• The amount of chemical in gms to be used per one litre of liquor is
called gpl.
• Example, for 40 gpl NaCl, 40gms of NaCl is to be used per 1000ml of
liquor.

9. • COLOUR FASTNESS
• It can be defined as the dye or colour present on the material
after the dyeing process should not easily come out during
• washing,
• rubbing,
• exposing to light,
• perspiration,
• saliva etc..

10. THANK YOU