Adding salt to laundry detergent will not make it look lighter in color. The color of laundry detergent is primarily determined by the ingredients and dyes used in its formulation. Salt, being a white crystalline substance, won't significantly affect the color of the detergent, especially if the detergent already contains vibrant dyes or pigments.
Laundry detergent manufacturers carefully design their products to be effective in cleaning clothes while also considering factors like appearance, scent, and safety. Altering the color of a commercially produced laundry detergent by adding salt is not a recommended practice and may not produce the desired effect.
If you prefer a lighter-colored laundry detergent, your best option is to look for a product that is already available in the desired color or opt for a detergent that is advertised as having a lighter hue. Keep in mind that the color of the detergent does not necessarily indicate its cleaning efficacy, so it's essential to choose a detergent that meets your cleaning needs and is suitable for the type of fabrics you're washing.