There's nothing like the smell of oil paints and painting medium in da mornin. Aside from killing a few brain cells with the fumes it brings me back to my youth when photoshop was non-existent and illustrators had to actually lift a paintbrush up and dip it into real paint and apply it to a canvas. The age of photoshop is here but there are still a good number of illustrators who prefer analog over digital. I dwell between both digital and analog, digital for speed and ease of use (no messy paints to clean up) analog I use for archiving and exposition of the original and selling to collectors. For me I still do an original oil painting from time to time it's important to leave a legacy of art for my sons.
Here is the start of oils on the "Dominator" piece. As you can see the more muted muddy color is the under-painting and under-drawing. In order to create very detail oils you must have a tight under-drawing or under-painting. You can achieve higher levels of detail quicker with a tight drawing before you start painting instead of going straight to painting with no base drawing.