Block Ink Medium & Extender is a versatile medium which can be used in two ways to create fantastic relief prints. Add to Derivan Block Ink colours to extend the colour and make them more transparent without loosing the "body" of your paint, as it would happen if you only added water. Just add from 1:9 to 9:1 ratio of Block Ink Medium & Extender to Derivan Block Ink colour. Up to about 1:1 ratio the colour will be extended, after this the colour will start to become more transparent, or Add Matisse Structure Acrylics colours to the Block Ink & Extender to create block printing ink from the paint. A ratio of 1:1 Block Ink Medium & Extender to Matisse Structure Acrylic paint colours is recommended.