50 ml pure magenta writing ink Suitable for use with our RIMIK mixing set. Octopus Fluids® writing inks are exclusive inks with pleasant shading, low feathery, optimal drying time, fast writing properties and a soft, supple pen. With our Rainbow Ink Mixing Kit, you can mix your own personal ink. And this is how it works: The kit contains four writing inks in the basic colors cyan, magenta, yellow and black. The three primary colors cyan, magenta and yellow can be mixed together in various mixing ratios. Depending on the mixture, you will get a different color. You can now carefully use the color black to darken your new color mix.