Glass Product Photography Tip #1: Use Backlighting
Backlighting is the preferred lighting setting when you have to shoot glass. That's because it won't create any problematic reflections or hot spots on your subject.
If you're shooting in a studio, use a softbox or diffuser behind your glass object to light it evenly.
If you use a diffuser, you may need to use two diffusion panels to make the light softer. As for softboxes, make sure you have the internal baffle attached for double diffusion.
The size of the softbox/softbox will affect the size of the dark lines that determine the shape of the glass.
If you want thicker lines, use a narrower softbox/diffuser and vice versa. I also recommend that you choose a white background behind or next to the object to help reflect all the backlighting forward.
