A hyperspectral imaging microscope system (HIMS) was recently designed for color truth establishment of histological tissue slides used for whole slide imaging (WSI) systems color performances assessment. Here, we present the estimation procedure of the colorimetrical performance of the HIMS by measuring the transmittance spectra of spatially uniform neutral density and color filters and deriving the color coordinates in the CIELAB color space. The transmittance and CIELAB results are compared to reference transmittance spectra and subsequent CIELAB coordinates provided by measurement of the same region of interest with a spectroradiometer. To measure the same region of interest, the spectroradiometer is equipped with a fiber probe whose tip is set in one of the eyepiece tubes of the microscope. The CIE 1976 color difference, ΔE^*_ab, is the metric used for goodness estimation.