I do not have a lot of working space, so putting a light behind a diffuser with the glass in front is out. What are other ways to light glass if you do not have a lot of room? My desk is 24" deep, but it is also got my monitors, so I got maybe 15" of free space to set up in, I was thinking of light to the side hitting the white background and maybe do the 2nd light above with some black foam core on either side to add to the outline of the glass?
Both suggestions can be done with limited space, but 2 good tricks for lighting glass depending on what you want to get for a result are a small light tent which can be done with a sheet and then bouncing light off the wall or foam next/behind it. Or you can also forgo a light tent go with a darker background and back light from below and shoot pointed straight on table level and drop ambient light down.
I been messing around with those frosted flexible cutting boards as diffusers. I did not think to try them on the glass to see. I did try bouncing the light off a piece of foam core but I had a pretty nasty shadow. I Beem using my white background and not liking the reaults. I will try some things out wih my black background.
You definitely need to add the light tent, you can buy a portable one that is a fold-able cube, or just use a sheet. otherwise you need to get the light below the table or way indirect so that its more ambient in nature. You see the sheet needs to cover the whole object and can be pinned up and hung from above, will have no background to the image but can act as a filter for shadows. Remember the larger and closer the light the softer it is. The other suggestion about light behind and from below looks something like this..
I have a light tent, but really don't like it. 24" cube is too big for my work area. I have used them in the past but never had a reason to have a wine glass or whisky glass in what I was doing. I am going to look for a smaller one or if I have to just build my own again. I have quite a bit of ripstop nylon here. I made a light dome from those cutting boards where I taped 2 together in the middle and arched it over what I was shooting and it worked well, nice even light that wrapped over. But I did not have anything reflective as glass in there. In a pinch I will cut up a cardboard box and make q quick light tent.
Another thought I have is rather than using that speed-light, have you considered some modest priced LED panels which would allow you to play with light in a continuous setup, they also have modifiers and depending on what you buy you can introduce color via RGB to your lighting if you are looking for something special.
Wouldn't even know what to look for in LED lights. I used flood lamps way back when, but after messing with strobes, never went tp anything else.
And it would have to fit on the space I have on my desk. My small light tent is ~16" cube and it just fits my desk depth-wise. width-wise I have 5-6ft
have you got a basic image of the item you want to photograph? have you considered light painting using a dark long exposure then lighting it in several passes on the same exposure
