I paint a lot of mechanized figures. Battlemechs, space craft, tanks, etc. It is common for all of them to be dominated by armor panels with finely engraved panel lines separating each plate, and it is the job of the miniature painter (small scale artiste?) to find a way to make that detail look it's very best.
I've seen a lot of advice and tutorials online about how people go about painting the armor plating details on small military figures, such as Battletech minis and the like. Most of what I see falls into one of two categories:
A. Paint the mini with your base coat and then apply a wash to darken the panel lines.
B. Paint the mini with your base coat and then use a fine brush or micron pen to ink in the panel lines directly.
The people giving this advice usually have dozens, if not hundreds of quality paint jobs to their names, so I know these techniques can produce wonderful results. Even so, I don't use either one, and it leaves me wondering: Am I the only one who uses a reversed technique?
When I set out to paint a miniature which is dominated by this kind of armor panel detail, I start out by painting the miniature with a shade color and work my way up from there. The amount of work I do shading depends largely on whether I am trying to produce a show piece or a table-top miniature, but the concept remains the same.
1. Paint the miniature with a shade color, based on the desired final look of the model. That is to say, if you want to paint something bright blue, you will start out by painting it a dark midnight blue. If the miniature is going to have more than one color in its final look, use multiple shade tones to block out the final paint scheme.
2. Paint each armor panel with the mid-tone for your final look. This color should be the desired 'end product' color for the panel. You can add shadows or highlights later, but the overall effect will be to make it look like your middle color. Try not to get any of your mid-tone into the panel lines during this step. To save time, you can try dry-brushing the model as a substitute for hand painting each panel, but I find that the results are not as good, and the panel edges will not be as clean and well defined.
3. Add in any shadows or highlights that are desired. One good option is to paint a fine highlight along the upper edges of each panel. Decide where your light source should be and pick out each edge that would be directly illuminated by that light.
The deep panel lines will provide some shading already, so I usually reserve it for show piece models. If you do choose to go for full shading, try to leave a bit of a gap between your darkest shading color and the base color filling the panel lines. It will allow you to simulate the lighting effects beautifully while still emphasizing the shape and appearance of the armor plates.
4. Paint in any further details, such as cockpit glass, weapon barrels, missile exhaust, etc. I will sometimes paint a dark metallic color right along with the rest of the shade colors in step one, but this is not usually critical with metallics.
I'll leave the decision about whether my technique produces satisfactory results or not as an exercise for the reader.