Since my personal work has been known to the public mostly through traditional mediums (such as oils and acrylics), people are often surprised when I tell them I also work digitally, and that most of my book covers are now done in Photoshop. The digital media is not new to me; in fact, I started to use it when I was doing concept artwork on "Dinosaur", in 1996. It took me a while to like it, but when you realise how much control you have on all your parameters, it can become addictive. In any case, I would never replace a classical training in traditional mediums with an exclusive digital training. Of course, Photoshop or any other digital package makes things easier on a practical level, but the artistic principles to follow are still exactly the same, and mixing real paint teaches you in depth how colour works in nature.
Step 1: Preliminary Sketch
This is the concept stage where I use a mix of imagination and observation of nature to build the structure of my illustration. I create a more refined sketch of the original concept along the way. At this stage lighting isn't emphasised - just lines that will define the elements and objects of the scene. Sometimes I also put black and white lighting in at this stage, but in this case I already have in mind a pretty good idea of what the lighting will be, so I go directly to colour (Fig.01).
This phase is the most critical one of all: I need to determine the exact balance of values and colours that will be the foundation of the painting. This is a block-in, so catching the general mood of the final image is more important than thinking of details, here. It has to be as accurate as possible to be believable. In some cases it will need adjustments later on, but these adjustments shouldn't be too far off this original block-in. I usually turn the sketch layer to Multiply in order to keep the sketch visible on top of the painting (Fig.02).