Sometimes it's the simplest shots that require the most carefully crafted techniques. That's my opinion of simple studio-style catalog photography, in which a product of some sort is photographed on a white background. It's a clean, clear, straightforward representation. But, as anyone who's ever attempted making a white background bright white knows, it's easier said than done. Trickier still is providing a truly isolated subject without any distracting shadows tying it to the tabletop. But, if you know the secret formula for isolating tabletop subjects on a shadowless white background, you'll never again have to fight with your file in Photoshop to create cutouts and eliminate those darn shadows. Here's the secret: use glass as the tabletop surface.
Many photographers photograph tabletop subjects on white paper. This is simple and straightforward, but it can also be tricky to keep the paper pure white without overexposing the subject. Another method is to use a shiny white tabletop surface, such as white Plexiglas, in order to allow reflections from the white background to brighten up the tabletop surface. But, if you really want to eliminate the shadows that connect subject to tabletop and surround the subject with a field of seamless bright white, using glass is the way to go. Here's how.
Start with a white, seamless backdrop rolled out as normal, but continue it from vertical background to covering the floor, as well. Bring it all the way out to the tabletop itself. Place two sawhorses where the table surface will be, and lay a sheet of glass (available from glass suppliers and mirror companies for about $100 in a quarter-inch sheet about 3x4 feet in size, with polished edges so you're less likely to cut yourself) across the sawhorses in order to form the transparent tabletop surface. Then, all you have to do is position the camera such that you see through the glass to the white background, and light the background and the subject independently by carefully positioning your lights and using flags to keep the background light from spilling onto the subject.
The technique I like to use for keeping my lights separate is to put as much space as possible (preferably at least eight feet) between the white background and the tabletop shooting space. Whatever type of light I use on the subject doesn't particularly matter; it's all about the background. For that, I position a broad light source above and behind the tabletop at an angle where it's covering as much of the background as possible but aimed away from the tabletop. Then, I use black foam boards (the 20x24-inch size is the most useful for me) to flag as much of the background as possible, creating a small opening just wide enough for the composition. This serves to help fight spill and to prevent flare from the background from creeping into the shot. This way, you can overexpose the background by a half stop or more to ensure it's bright white all the way from front to back. That's the secret of the shadowless shot: the bright white background, seen through the clear glass tabletop.