HunterLab instruments are visual range spectrophotometers, meaning they measure the color of your sample. That being said if you can see a visual difference in the appearance of your sample then our instruments are capable of quantifying that.
I would recommend you review our Basics of Color Theory Powerpoint which can be found on our website here: http://www.hunterlab.com/application-notes.html
This runs through a little bit of how our instruments work and how it relates to the color of your products. Please let us know if you have any additional questions after reviewing this.