An apparatus for measuring a color of a non-solid colored sample, the apparatus comprising: an integrating sphere comprising: a sensor port ; a sample port ; a light port ; a light source positioned near the light port for illuminating the interior of the integrating sphere; and a plurality of registration marks affixed to an interior surface of the integrating sphere , outside a periphery of the sample port , wherein the plurality of registration marks comprises: a first registration mark (202 1 ) and a second registration mark (202 2 ) collectively providing four constraints for correcting up to four registration errors in an image, the registration errors including displacement along two axes, image dilation, and zoom; a camera positioned near the sensor port arranged to capture a plurality of images that include a sample positioned at the sample port and the plurality of registration marks ; a processor to control operation of the light source and the camera ; and a plurality of color filters positioned between the integrating sphere and camera , wherein the processor is configured such that each image of the plurality of images is captured using a different color filter of the plurality of color filters; wherein an optical axis (O) of the camera passes from the camera , through at least one filter of the plurality of filters , and through the integrating sphere from the sensor port to the sample port . an integrating sphere comprising: a sensor port ; a sample port ; a light port ; a light source positioned near the light port for illuminating the interior of the integrating sphere; and a plurality of registration marks affixed to an interior surface of the integrating sphere , outside a periphery of the sample port , wherein the plurality of registration marks comprises: a first registration mark (202 1 ) and a second registration mark (202 2 ) collectively providing four constraints for correcting up to four registration errors in an image, the registration errors including displacement along two axes, image dilation, and zoom; a sensor port ; a sample port ; a light port ; a light source positioned near the light port for illuminating the interior of the integrating sphere; and a plurality of registration marks affixed to an interior surface of the integrating sphere , outside a periphery of the sample port , wherein the plurality of registration marks comprises: a first registration mark (202 1 ) and a second registration mark (202 2 ) collectively providing four constraints for correcting up to four registration errors in an image, the registration errors including displacement along two axes, image dilation, and zoom; a camera positioned near the sensor port arranged to capture a plurality of images that include a sample positioned at the sample port and the plurality of registration marks ; a processor to control operation of the light source and the camera ; and a plurality of color filters positioned between the integrating sphere and camera , wherein the processor is configured such that each image of the plurality of images is captured using a different color filter of the plurality of color filters; wherein an optical axis (O) of the camera passes from the camera , through at least one filter of the plurality of filters , and through the integrating sphere from the sensor port to the sample port . <EOS>