Long years of development went into the patented thermosensitive Metamo ink that gives the Pilot Frixion line its main selling point. One of the most difficult tasks was to increase the temperature range for when the color appeared and disappeared. Microcapsules that form the pigmentation contain an equal mix of three substances: 1) special types of dye that change between colored and colorless forms 2) color developer 3) compounds that regulate the temperature at which the color transition...