thanks all for your help.

a bit more info about what i am trying to achieve. i am interested in motion tracking systems and trying to integrate a camera into some software i've written. i have been rolling a white golf ball across lawn at different speeds but the system isn't working well when the ball is rolling at slower speeds. i did a bit of research on google regarding how to make the ball stand out more against the background and monochromatic filtering seemed like a possibility. i haven't read much about polarisation but will certainly have a look in this direction. unfortunately distance from the camera lens and lighting are variables that i can't control in this instance. i would appreciate hearing your thoughts and would be happy to answer any further questions.

thanks again

ted