Because x-rays travel straight through most mediums they are near impossible to focus which means getting a clear image has to involve other factors. These factors are easily demonstrated by looking at shadows.
Equipment
Light box or torch
Retort stand
White paper
object to throw a shadow
Method
Set up the light source so it is held still above the bench with the retort stand.
Measure the height of the light, make sure it is at least 50 cm above the bench
Place an object at 30 cm above the bench and observe the shadow.
Move your object up and then down, how does this effect the shadow?
Move the object until you get the sharpest shadow. What position is the object?
Make a conclusion about how to get the clearest shadow and what this means for taking a clear x-ray