# Calculation and Working Procedure of Lab Dip in Textile Industry

Last Updated on 15/06/2021

What is Lab Dip?
Lab dip is a process by which buyers supplied swatch is matched with the varying dyes percentage in the laboratory with or without help of spectrophotometer (DATA COLOR). In either way we can say that the lab dips for a particular garment style, containing many shades of the fabric color which the buyer is asked have to be sent to the buyer for the approval before going for further production. Lab dip calculation is the major task in lab dip process. Besides, accurate lab dip calculation plays an important role in shade matching and detaching the characteristics of the dyes and chemicals are to be used in the large scale of production. So this is an important task before bulk production. A Pantone color reference or sometimes a swatch cut from another fabric is given to the lab to match to.

Preparation for Lab Dip Calculation:

Common Stock Solutions:

1. Red – 0.1%, 0.5%, 1.0%, 2.0% (very common)
2. Yellow – 0.1%, 0.5%, 1.0%, 2.0% (very common)
3. Blue – 0.1%, 0.5%, 1.0%, 2.0% (very common).

Preparation:

1. To prepare 0.1% Stock solution, it is necessary to mix 0.1 g dye and 100 cc water.
2. To prepare 0.5% Stock solution, 0.5 g dye stuff is mixed with 100 cc water.
3. To prepare 1.0% and 2.0% Stock solution similar procedure is followed.
4. To prepare 10% Stock solution of Soda ash, 10 g Soda is mixed with 100 cc water.

0.5% to 5% shade for the goods.

Lab Dip Calculation:
Usually following calculations are followed:

1. Dye Solution = (Shade % * Sample Weight) / (Stock solution %)   (cc).
2. Salt = (Shade % * Liquor) / 1000 (gram per liter, gpl).
3. Soda Solution = (Shade % * 100 * Liquor) / (1000 * Stock solution %)    (cc).

• Sample wt. = 5 mg
• Material liquor ratio = 1: 10
• Total liquor (5 * 10) = 50 cc
• Dye solution required = (5 * 0.5%) / 1% = 2.5 cc
• Salt solution required = (50 * 25) / (20 * 10) = 6.25 cc
• Soda ash solution required = (50 * 10) / (20 * 10) = 2.5 cc
• Water required {50 – (2.5 + 6.25 + 2.5)} = 38.75 cc

More lab dip formula and calculation:

(A) Required Dye (ml) = (Fabric weight x Recipe%) / stock%

(B) Required Chemical (ml) = (Total liquor × recipe amount (gm/l)) / stock.%

When,

• A Fabric Weight = 5 gm
• Recipe = 2%
• Stock solution = 1%

Required dye = (Sample weight × recipe%) / Stock solution
= (5×2) /1
= 10 ml

When,

• Fabric Weight = 5 gm
• M:L = 1:7
• Salt recipe amount = 15g/l
• Stock soln = 2%

Required salt = (5×15) /1000 × 2/100
= 37.5ml

Working Procedure in Lab Dip:
All ingredients had been taken according to the recipe into the pot of sample dyeing machine. At a room temp the material had run then after 10 minutes started to rise the temperature at 1°C/ min to get 60°C temperature. For performing the required dyeing temperature it took 30 minutes. The material had dyed at 60°C for 45 minutes. Then the temperature was reduced at room temperature within in 10 minutes. The fabric washed in cold water and then the material was washed in 1 gm/l soap solution (liquor ratio 1:20) at 90°C temperature for 15 minutes. Then after rapidly cold washing the material was dried and preserved. And then check the shade match with the required sample by the lighting box. Then send to buyer or merchandiser for approval.