The cationic dyes of formula specified in claim 1 are suitable especially for colouring keratin-containing fibres, more especially for colouring hair. The system further includes an optical processing system configured to receive and process the image from the display output of the low electromagnetic radiation display to determine device data based on the processed image, and a data transmitter configured to transmit the device data to a remote data collection device. The circuit disclosed herein detects the state of the core voltage and disables the output drivers when the core voltage is detected as being off. A first memory stores at least the control points and at least one lookup table stores the cubic weighting factors. Dielectric filler material may then be introduced through the one or more openings to the recesses and, optionally, between the semiconductor die and interposer substrate.