In the latest release (jhove 1.3), the reported colorSpace element is merely a numeric value as described in MIX 0.2. In MIX 1.0 and 2.0, the colorSpace element is a string with suggested values defined in the data dictionary (section 184.108.40.206 of mix 1.0 data dictionary on page 19). On that section, it says "colorSpace recorded here should be a text description. Though element type=string is technically defined as one or more characters, it is not appropriate to record the numeric encoding for colorSpace that may come directly from the image file header. Text descriptors should be used to facilitate transparency of information recorded in this element. "
Currently, Jhove reports colorSpace as numeric value. It seems from the data dictionary, a more descriptive string value will be better suited.