Transparent objects are difficult to cut out convincingly because they don’t just sit in front of the background—they bend, reflect, and transmit whatever is behind and around them. In practice, that means a “perfect” background removal is often not possible.

The most useful approach is to shoot the object against a plain background that is similar in tone or color to the background you plan to use later. That helps the refractions and reflections look more believable after compositing.

Lighting matters too: with transparent subjects, you usually light what the object reflects rather than the object itself. Match the lighting direction and quality to the scene you plan to place it into.

A black background can sometimes help define edges, and in editing you may be able to place the object on a new layer and reduce opacity, but this is only a partial workaround—not a true replacement for realistic refraction from the final scene.

So the short answer: plan the final background in advance, use a simple similar-colored backdrop, and match the lighting as closely as possible.