A long-time lurker, first time poster here
I spend my not-so-frequent free time to do some industrial design/vehicles/environment concept art. Here's some of it
I know it is generally frowned upon, but I can't help it. Some Star Wars related things -- yeah, I know it's lame, but hey, since the day when i was 6 and my mom took me to see "A New Hope" and this opening scene hit me between the eyes, my life has never been the same In fact, since this very moment I knew what I want to do in my life
Now, since I am entirely self-taught and I do believe in sharing knowledge whenever possible, here's a quick tutorial of the technique I use. I use it in production mode, it is real fast and can be used directly in the production pipeline (I work in the Games Industry). I have a 3D background, so if some of the terminology and explanation sound a little deviant, well, that's the reason
Software used: Sketchbook and Photoshop
I start usually with resolution around 1900x1280. I use white background -- I know most of the people consider it not very useful, but for me it works very well to notice the initial problems in the sketch. I put the three axes for Isometric projection -- for concept work I personally consider isometry to work better than perspective -- it helps greatly the 3D guys to get right the volumes and proportions.
I start in Sketchbook, I love the way it works for Industrial design. By all means, one can start with Photoshop directly. I make a very rough sketch with a hard brush with very low opacity (10-12%)
I tighten the sketch with a brush 1/2 the size of the previous one and 2x opacity (20-25%)
I make the final version of the lineart, tight brush, 100% opacity, pure black
The cleaned up lineart. Here's where with a heavy heart e leave Sketchbook aside and move to Photoshop (damn layers incompatibility)
I put down a basic blocking color. Helps a lot further on Usually i pick up something in a very desaturated cobaltblau.
I pick up the direction of the light and block out the main shading. At this stage, i don't bother with nuances and value of the shadows -- just simple hard shadow blocking out. From a 3D perspective, after the renderer draws the edges of the geometry it starts working on the shading -- and here we are, doing the first part of this step.
With a soft brush, I put the "shading pollution" -- its 3D equivalent is called "Ambient Occlusion" at the areas where it usually takes place. The "shading pollution/AO" takes place because of bouncing of the light from areas with slightly different surface properties and bounces around losing its photon energy at a different rate.
I very sketchily and superficially mark the directly illuminated areas. I personally prefer to keep the illuminated areas up by simply not shading them. This is the 2D equivalent of the self-illumination material property (in certain 3D packages they mix it with the ambient color which is pedagogically incorrect, but anyway)
Here comes the Photoshop chicanery One of the most important steps. I make a few textures, and using the magic Free Transform Tool I conform parts of these textures to the forms and volumes defined by the lineart -- mainly just the large areas (the smaller ones I fix with the brush). The curvatures take usually 5x as much time as the straight ones. In 3D terms, this the moment when the renderer begins to read from the texture using the information provided in tangent space (the UV coordinates, in a simpler term). After I place the textures, I put their layer in Multiply mode so that they pick up from the color and the shading underneath them.
I take away the lineart and start little by little to tighten the image using the specular areas. I also start painting on top of the jet engine texture so that I can remove it later (otherwise it looks a tad too sterile). I also beging putting in details wherever I feel like doing it.
This is the result thus far when I switch on the underlying layer that has the shading in it -- with the Multiplied textures on top of it. I continue tightening the image and put in details.
The main volumes are covered already, I continue putting in details
More detail, this time around the lights are on, they are the main reference in this case as to what size is the vehicle.
I put in the paintjob. The hull is painted white, with Burgudy as its red counterpart. Both the white and the red are in Overlay mode so that let sufficiently the material and the shading to pass through them. I personally prefer to keep the paintjob Overaly layer at around 40-50% so that they don't mess up with the layers below them. After I block out the paintjob scheme, I take some irregular brushes (I've made a custom brushes set precisely for this kind of tasks) and scratch up the paint good in order to give the spaceship some history.
Final step. I put in a neutral background to increase the readability of the concept. I resize it down to a reasonable resolution, and smack a Sharpen on it if need be. I pass over with Dodge or Burn soft brush at a veeeery low intensity -- 3-7% -- and put in a frame and the text.
Et voila Takes just a couple o'hours.
The steps will look very familiar to the people with 3D background. Indeed, they have direct equivalents in the course of the rendering process (ot compositing, for this matter). For the people with Classic Art background (whom I simply quietly admire from the side walk) this approach might look very strange and unintuitive -- then aiagn, it might not By all means, this is an entirely digital technique which i am pretty certain can not be duplicated with a traditional media.
I hope this quick tutorial has been of help to someone.
Have a very nice day