Bump v’s Displacements.
Basically a displacement shader will displace the actual geometry at rendertime (hence why the viewport does not update when enabled). Bump mapping works by displacing surface normals. In essence the actual surface is not deformed or displaced, just the shading normals of the geometry. You can see this by moving the camera to a glancing angle and render…the surface will be completely flat. Normal maps work in a “similar” fashion. For close up shots, displacements 100%. Distant shots, bump mapping will suffice.
As for the map that I put in the RGlossiness channel. The thinking behind this is, the highlight (for the clear coat shot) should be fairly smooth due to the multiple layers of clear coat and not really be affected by the chair geometry, that’s why I removed the map from the HGlossiness channel. Reflections, I decided that the underlying geometry should affect the reflections, thats why I placed the map in the RGlossiness slot. Perhaps not 100% realistic but some degree of artistic-ness can sell a shot.
The nails basically want a dark grey colour, broad specular highlight, and a touch of relectivity. In your new shot, I think the specular on the nails on the side of the chair is too broad, looks kind of matte-plastic.
As for the displacements on the side of the chair, I wouldn’t worry about that. Reason being is that: The side of the chair is quite literally a machined surface. It would be quite smooth, which play’s true to the UV mapping you have on the sides.
IOR: This is an old post, but still exceptionally packed with IOR information. Please bookmark this, it’s invaluable, (CTRL+F for the web browser search function really help, as this list is massive). http://forums.cgsociety.org/archive/index.php?t-513458.html
As for the timestamp on the render. That’s easy!
At the bottom of the render there is a downfacing arrow called “Show Stamp Controls”. Click this and it expands a lower area with a lot of confusing writing. This confusing writing basically tells you what will be shown on the bottom of the image. Each piece of information has a seperator “|”. I just deleted all the un-relevant information for what I was trying to achieve. When that is done you “Apply Stamp”.
See screen shot of said buttons.
Hope this helps.