Numerous papers have been written regarding techniques to translate color measurements from an RGB device into some standard color space. The papers seem to ignore the mathematical 'truth'...that the translation is impossible. Do these color transforms work, or under what conditions do they work, and what are the limitations. Why is it that they work. In this paper, light emitting diodes (LEDs) are viewed with a color video camera.It is seen that, for the spectra of LEDs, transforming from the camera color space the XYZ tristimulus space leads to very large errors. The problem stems from the fact that the RGB filter response are not a linear combination of XYZ responses. Next, it is shown that the transformation of CMYK halftones does not pose such difficulties.Here, it is found that a simple linear transform is relatively accurate, and some options to improve this accuracy are investigated. Several explanations are offered as to why transforms of CMYK are more accurate than transforms of LEDs. To determine which of the explanations is the most likely, linear transforms are applied to a variety of collections of colors.