1 & 2
You should test the exposure times of your paper before getting started. How long exposure needs the paper to get a slight gray, and how long does it take to reach a well settled black? In the first picture shown, short exposure time has been chosen. The light falls straight from the top. Because of the short exposure, you get a gray background. You see the silhouette of a can-opener.
3 & 4
If you increase the exposure, and exeed the black point,the paper will react with the reflected light from the object. In that case, the silhouette will disolve and transform itself into a three dimensional illusion (as you can see in pictures 3 and 4).
In picture number five, the object was exposed from the right side, at an angle of 180 degrees. Here you can see that the usual form of a can-opener faded away.
The important role of the exposure angle is particularly shown in picture number six. The direction also makes a difference. Even if the exposure time and direction have changed, the angle still is the same (180 degrees).
If you combinate light from the top and from the side, you obtain parallel results, as shown in picture seven.
Here was first exposed from the top, and then diagonal from the right bottom side. The result is completely different if two side lights are set (picture eight).
In this example a further component was added: The can-opener was exposed from the right side, then moved, and exposed a second time.
Shadowgraph number ten shows a possible enlargement with a one to one silhouette. Therefore, you have to increase the distance between the object and the photo paper.
You can also make a reflex copy if you wrap the paper around the object.
As you can see in the last picture, there are possibilities to create a three dimensional background. All you need for exemple, is a flat transparent object, so you can place other things on top of it.