Dyeing clothes a neon color isn't for the faint of heart. Because the colors are so bright, using the proper dyes and associated materials is essential. Know what your fabric is made of, prepare the materials in advance, and read the instructions thoroughly. Depending on whether your garment is cotton or wool makes a difference in not only the dye brand, but the additives, as well. A tip? Silk fabrics can use either fiber-reactive or acid dyes.
Select your dye by analyzing the fabric. Fiber reactive dyes are best for cotton and other natural fabrics, such as linen. Acid dyes are necessary for wool. Silk fabrics can accommodate either dye. Pre-washing the fabric ensures that the color will take to the fabric evenly. Also, fabrics that have been treated with starch or are permanent-press in nature may end with uneven results.
Mix the dye, following the instructions on the dye bottle. You may need to add salt to the water. Pour the mix inside the plastic bottles. If possible, wear a face mask; it's possible to develop facial irritation from overexposure.
Soak the fabric in a soda ash and water solution for 15 minutes to one hour. Use a ratio of 1 cup of soda ash for 1 gallon of water. Don't use baking soda. Soda ash can be found at swimming pool supply stores.
Apply the dye while wearing gloves. Place the garment flat and drip or spray the dye onto the fabric. Keep the fabric wet for at least two hours, preferably for 24 hours. Place the fabric in a plastic bag to keep it wet.
Wash the fabric in the washing machine with cold water, then twice with hot water. You don't have to rinse the fabric before putting it in your washing machine.
Warning
Be certain to mix and use the dye in a well-ventilated area. Wear gloves; dye stains skin.