Mathematical models have been successfully used in a number of areas related to digital color imaging. In general the focus has been on using models to characterize the color reproduction properties of a device or to embody specific aspects of color perception. However, models can also be used to estimate color tolerances. This paper demonstrates how a simplified CIE gain, offset and gamma or GOG model for the CRT and CIECAM97s can be used to determine hardware and viewing condition tolerances for an sRGB monitor. Error curves and surfaces are derived for the gamma, offset and phosphor chromaticities. Similarly, error curves and surfaces are computed for luminance of the adapting field, adopted white point and the surround.