and SMPTE C colorimetry were not taken into account - see the next section. CRT display In order to convert Y, R-Y and B-Y to RGB you need to consider how Y originated, namely: Y = R * 0.30 + G * 0.59 + B * 0.11 Thus you need to use the following formulas: R = R-Y + Y B = B-Y + Y G = (Y - 0.30 * R - 0.11 * B) / 0.59 But at first you need to spend attention to the fact that for all colors that have no chrominance - thus black, gray and white - R-Y and B-Y are not 0% but all have an offset of 47%. So you need to subtract this offset from all R-Y and B-Y values at first. Due to the fact that in practice this one step will never be done alone, it's no problem that some results will be negative: Now you can do the conversion to RGB. All results must be in the range from 0% to 100%: You might come to the conclusion that the erroneous value of 113% for R of color "light red" results out of a typo within the datasheet and there R-Y must not be greater than 80%. But if you measure the output signals of the chip with an oscilloscope, you'll find that all values in the table are correct. So the error is inside the chip and drives the red signal into saturation. For this reason this value is to be corrected to 100%. Furthermore, you need to consider that up to that time only cathode ray tubes have been available for computer monitors as well as for televisions, and that these CRTs had a gamma. The TMS9918 series chips had been designed to work with televisions and their CRTs had a gamma of 1.6 (remark: CRTs of Macintosh monitors had 1.8 and the CRTs of PC monitors had 2.2). Flat screens do not have gamma. For this reason the colors of the TMS9918 look somewhat pale here as you can see in the first table above. The below table uses the gamma-corrected values, which are (written in hexadecimal because this is needed by Wikipedia's coding): Note: The used steps are: Round all values to two decimal places, then raise to the power of 1.6 for gamma correction and finally transform the range of values from