I agree with the above replies in that you need to eliminate any shadow behind the pen. If you are using two separate sheets of material for the background ... get a longer single piece for the background, tape the front edge down from edge to edge (helps to avoid wrinkles), and then elevate the very back edge up, again taping the material to something from edge to edge, until a
gentle curve is formed. Keep the pen as far toward the front edge to 'hide' the curve, light the pen, snap the shutter. LOOK closely at image in the viewfinder for problems in lighting, subject angle, re-take the picture if necessary. Then post away.
Do as much as possible to have the image you want in the viewfinder first. It is far easier to do your composition in the viewfinder than with a program to alter the image later.
To kind of 'paint' with light' you can put a light in the back of the background material and let the light bleed through to the front. Just don't get so close to the background that you have a 'hot spot' of light, unless you do that on purpose for some type of special effect. Be careful of developing any shadow at the base of the curve again.
Have fun ... experiment with different colors to accent the wood.