With the changes in the actual regain of textiles, there are changes in the weight of the material which affect the count and strength of material. If the actual regain of the specimen in known, it is possible to calculate the count and strength corrected in the standard regain.

Corrected Count

The count of yarn corrected to the standard regain is known as corrected count of the yarn.

If N is the count of the yarn at the actual regain Ra (Regain at the time of testing) and Rs, is the standard regain, then

N (100 + Ra)Corrected count Nc = ------------------

100+RsThe above formula is used for indirect system of yarn numbering.

For direct system of the yarn count, the following formula is used. N (100+Rs)

Corrected count Nc = ------------------ 100 + Ra

CORRELATION OF YARN COUNT AND STRENGTH FOR HUMIDITY CHANGES

1. Gravimetric Method2. Chemical Method3. Dew point Method

Methods to measure the Relative Humidity

1. Hair hygrometer or Thermo Hygrograph2. Electrolytic Hygrometer3. Wet and dry bulb Hygrometer

Instruments Used to measure Relative Humidity

Absorption curves of various materials

WET AND DRY BULB HYGROMTERWET AND DRY BULB HYGROMTER

Conditioning Oven

Thermo Hygrometer

A - chart B – Pen arm

C – Pen D – Bi-Metalical helical coil

E – Band of human hair

E

D

Sling Hygrometer