Illustration Colors are lightfast. We use the same exterior-grade pigments we use to make our Wicked Colors and Auto Air Colors. The difference is in the resin. Unlike Wicked Colors and Auto Air Colors which air dry to a cured, non-soluble coating, Illustration Colors are re-wettable with an amine such as WindexTM. This is one of the key characteristics behind the creation of our Illustration Colors. Another key characteristic this resin offers is soft erasing. Unlike our Wicked Colors which erase hard, Illustration Colors are very easy to erase within the first 48 hours after application. After 48 hours, Illustration Colors harden making erasing more difficult and similar to how our Wicked Colors erase.No reduction is necessary. Illustration Colors atomize and spray excellent through small airbrush tip sizes down to 0.15mm at low psi settings direct from the bottle. Unlike Wicked Colors, Wicked Detail Colors and Auto Air Colors which are intended for application with a spray gun direct from the bottle, Illustration Colors are intended solely for application with an airbrush and are not designed to cover as a base color. Reducer and Transparent Base are offered in the Createx Illustration Line to provide artists the option to further adjust viscosity and transparency based upon their subjective preferences. However, most artists will find the Illustration Line to be excellent straight out of the bottle with little need for adjustment.Illustration Colors may be topcoated with a urethane clear. Createx Illustration Colors work excellent as custom, automotive candy colors with an airbrush; however, they are not designed for use with a spray gun as the extreme low viscosity will not allow for a proper spray pattern.