CYGM gives more accurate luminance information than the Bayer filter, hence a wider dynamic range, but at the expense of color accuracy. This is because the cyan and yellow components of the colour filter array do not produce a true monochromatic yellow or cyan but are rather modifications of the filters used to absorb 'color'. Under the conventional trichromatic theory, a 'green' measurement is taken by placing a color filter which absorbs 'red' and 'blue' in front of the light sensor. A 'blue' measurement is taken with a 'green' and 'red' filter, and a 'red' measurement with a 'blue' and 'green' filter. RGB is therefore derived by using 2 color filters for each measurement. This means in practice that much of the light that falls upon the sensor array is absorbed by the filters. The CYGM color filter array differs from the standard Bayer filter by using only a single color filter for 3 of the 4 sensors. This produces a broad spectral response and therefore makes measurements more accurate in respect to luminance but makes it more difficult to determine color information accurately. While 'green' is unaffected, color inaccuracy arises from the fact that the red and blue sensors are in effect conflated into 'magenta' and 'cyan' sensors. This is shown by a graph of the spectral response of the CYGM sensor. While the CYGM filter found widespread adoption in the early years of digital photography, at the time a rival of the now standard Bayer filter, it is now considered obsolete. CCDs that used it include the 3 megapixel Sony ICX252AK and ICS252AKF CCDs with a CYGM color filter array were initially adopted by both Canon and Nikon when these companies transitioned from film photography to digital. Many Canon models of the 1999-2000 period, such as the PowerShot S10, the Canon Digital IXUS S100, and the Canon PowerShot G1 used sensors with this colour filter arrangement. Whereas Canon adopted the now standard Bayer filter across its entire range when it introduced the DSLR, Nikon continued to produce and sell a range of mid-range enthusiast digital cameras using CYGM sensors for a period of approximately 5 years. From the prominent Nikon Coolpix 995 to the Nikon Coolpix 5700.
