I suggest you experiment by scanning a slide as if it were a photo.  Place in the scanner with the cover down.  As shown here, the reflected light is very low and should contribute little to the image scanned in using the method below. 

    Also, will the reflected light contribute toward improving the image or degrading the image?

 
(Click on photos with blue boarder for larger image)
 
    Trouble Light
    Trouble Light Label 
    Setup for Scanning 
    - Lay slide or negative on glass 
    - Put 5 layers of wax paper on top 
    - Place light directly on top 

    I can do two slides at one time. 

    Start the scanning process. 

    (Note: suspending trouble light up one half inch or degraded the scanned image.)

    View from inside the Scanner