I am in the process of creating an online shop that will sell plexiglass(acrylic) products. The material we use is crystal clear just like glass.
Now, what i need is to have a completely white background seen through the glass. If it was not transparent, i could have used the lasso tool in PS to cut the object and place it on a white background but my ''slide'' paper is visible through the glass.
How do professional photographers solve this problem?
I would use a cyclo wall setup or to use less fancy talk, a curved piece of white cardboard or paper. You light the background a couple stops brighter than your acrylic and you have a nice pure white seamless background. If you have a large piece of flat clear acrylic placing your product on it may provide for a pleasant reflection.
You will probably need to play with putting a different color light or a colored flag on your object to get some better reflections in your products as they may be too transparent to look good on pure white without some color.
Here's the trick to shooting clear subjects
The trick to shooting small clear objects is to give them their own tiny background that is lit off-camera and that is trimmed so that nothing shows from the camera viewpoint.
Let's take a frosty glass of beer. Cut a card to place behind the glass that bounces light back through the beer toward the lens. Vary the amount of light by changing the distance from the light source to the reflector card. It will help lift the subject off the background, visually.
The problem with shooting against a white background is that transparent object become "blackline." The edges appear dark. It's difficult to light the subject. The more light you use is refracted away making the contrast even brighter.
The opposite happens when you shoot against a black background and the object becomes "whitelined" and the middle becomes dark and the edges glow when you pour more light on the scene.
Find out more by studying glassware lighting and catalogs of glassware
I think Patrick's answer is a good. This is called a high key backdrop so you may want to search for that as well. Here is one tutorial. http://photo.tutsplus.com/tutorials/lighting/beginners-guide-to-shooting-high-key/
There used to be software that would have you take a picture of a transparent object first with a black background and then white, with the same lighting. Using those two images it made a transparent one which would allow you to change your background scene after the fact. I can't remember the name, but it was pretty impressive. If I can find it I'll update this.
