Chromacryl Textile Medium Add Textile Medium to Chromacryl Colours to make an immediate and effective textile paint with washfast durability. You can paint free-hand, block print or silk screen designs onto most natural fabrics. When dry, “fix” the colour into the fabric with heat. This can be done by ironing the fabric on a hot setting for at least 2 minutes. Place a sheet of aluminium foil over the fabric to be ironed to prevent the textile paint from sticking to the iron. Note: when silkscreen printing with any acrylic based product including Chromacryl, it is advisable to add about 10% of retarder to the mixture on the screen, and the process must be carefully supervised to make sure that the paint does not dry on the screen. Consequently, silkscreen printing projects are usually simply one colour jobs for articles such as T-shirts.