Matisse Derivan Screen Printing Ink has been formulated as a safe, non-toxic silk screen printing ink for fabric and tie-dyeing. It can be used in the classroom or at home safely without the worry of being exposed to harmful solvents such as white spirits, turps or thinners. Matisse Derivan Screen Printing Ink is water-based and washes up in water (before it is heat set) but has excellent rub resistance and lightfastness once heat set. All the colours may be intermixed to form bright secondary and tertiary colours. White (Opaque) may be mixed if pale pastel opaque prints are desired on dark colored fabrics. The Screen Reducer is a thick milky colored paste which dries colorless and transparent. It is used for intermixing with standard printing colours in order to extend deep colours into pale or lighter transparent shades (Red into transparent pink, etc.). It is mainly for white or pale fabrics. Best results are obtained from absorbent fabrics; avoid waterproof fabrics as they tend to inhibit penetration and repel the water-based colors. Clean up is a breeze! Simply wast all utensils, brushes and hands with soap and water to clean up!