The colors of cotton clothes can change after a wash due to various reasons, including:
Fading: Cotton fabrics, especially those that are dyed with natural or low-quality dyes, are prone to fading when exposed to water, detergent, and agitation during the washing process. The dye molecules can break down and wash out, causing the colors to appear less vibrant or faded.
Bleeding: Some dyes used on cotton fabrics may not be colorfast, meaning they have a tendency to bleed or release color when they come into contact with water or other substances. This can result in the transfer of color from one part of the fabric to another, leading to a change in the overall color of the garment.
Incorrect washing techniques: Washing cotton clothes in hot water or using harsh detergents can contribute to color changes. High temperatures and strong chemicals can strip away the dye or alter its chemical structure, leading to color loss or changes.
pH levels: Some detergents or water with high alkalinity can affect the colors of cotton clothes. The pH levels of the water and detergents can interact with the dye molecules, causing them to change or fade.
To minimize color changes in cotton clothes, it's advisable to follow the care instructions provided by the manufacturer. This may include washing in cold water, using mild detergents specifically designed for colored fabrics, turning the garments inside out before washing, and avoiding prolonged exposure to direct sunlight while drying. Additionally, separating dark and light-colored garments during the wash can help prevent color bleeding.