Fabric Color Approval Procedure

This guest post is contributed by Todor Stojanov

In the process of product development, the customer and supplier need to define the material (fabric) color for the product that needs to be produced. There are several phases in completing of this procedure like,

1. Define Color Standards 
2. Lap dip process
3. Color matching

1. Define Color Standards

The first step is to define the color standards for the fabric dyeing, which should be used as a frame for the future production. This means that the customer and supplier will set the acceptable limits for the color variations. The customer must provide a reference sample to the supplier of the color requested and keep a sample swatch for their future reference.

The piece provided to supplier needs to be as big as possible, so it will be easier for the supplier to hit the right color. The color matching will be different if the composition or weight of the provided fabric is different. Please notice that in case of using a Pantone Color Swatch, the printed colors on the paper will look different than on a fabric texture.

2. Lab Dip Process

After defining the fabric color, the next step is making a Lab Dip sample. Lab dips are done in the laboratory environment with purpose to provide a visual aid on how a color will look when it is dyed. The actual production sample will vary from the lab dip that is provided. Remember that the lab dip is produced in a beaker and is not an actual production run. It is not possible to lab dip enough fabric for a sample cap or garment. When the goods are dyed in a real production run, the conditions are dramatically different from the laboratory. Production of the fabric will not begin unless a lab dip is approved or the customer waives the lab dip processes. Once a lab dip is approved the dyeing will start only according to the approved lab dip. Lab Dib machine is presented on Fig.1.

Fig.1. Lab Dip Machine.

The machine can be used for dyeing of fabric, yarn and loose stock samples. Rocking bars apart from up to down motion rotate at 70 RPM and their length can be adjusted between 25mm to 50mm. The number of beakers is 12 with up to 95C possible dyeing temperature.

3. Color Matching

The supplier should make an effort to get the special dye lot as close to the color standard / lab dib as possible. But, no two dye lots are the exact same color. However, a commercial match to customer’s color will be achieved on a special dye lot. A commercial match will be a similar tone that may be slightly darker or lighter than the color standard. A fabric color matching cabinet machine presented on the Fig. 2 can be used for detection of color difference between the production lot sample and the standard one. The usage of this machine is for the visual assessment of color under standardized and controlled environment. It allows

Fig.2. Fabric Color Matching Cabinet

person to evaluate color samples under different light sources.

The machine provide: Artificial Daylight Fluorescent Lamps (D-65), Tungsten Filament Lamps, Tri Phosphor Fluorescent Lamps (TL84), Ultra violet Black Lamp (UVB), Cool White Fluorescent Lamp (CWF), Hour Meter.

When the supplier starts the lot dyeing, he needs to provide a lot sample to the customer for approval. The form presented in Fig.3 can be used to compare the original watch sample with lab dip samples and select the one that is acceptable for the future production.

Fig.3 Lap dips approval form

There are many variables that can influence in variation of the color or appearance which make it impossible to get an exact match. Some of these variables include:

1. The color swatch was produced from a different mill with different processes, equipment and dye stuffs. 


2. Dye stuffs used to produce fabric vary in shade from lot to lot. 


3. Atmospheric conditions such as humidity vary day to day. 


4. The natural (greige) goods vary from lot to lot. Some woven goods are very clean and the dyes absorb deeply while others may not take as deep. 


5. The cotton from different crops will absorb dyes differently. 

During the dying process, all of these variables must be constantly monitored and changes are made to keep the color as close to the color standard as possible. Even while making these changes, there will be slight variance in shade from the reference sample, to the lab dip, to the actual production run. All these variances should be in the acceptable tolerance that was arranged in advance between the customer and supplier.