When it came to painting Iron Man I knew recreating the studio paint job was going to be a challenge. I'm a novice at non-metallic metal and the studio Iron Man is a very good example of painting nmm. Simply copying the placement of light and shade was going to be tricky and also not very instructive for myself or any readers.
I've long been intimidated at nmm, believing it one of those techniques that's for the really good painters only. Many early renditions of nmm were very stylized with complex arrangements of light and shade and super smooth blending. Not being particularly creative or technically accomplishment meant I considered learning nmm a waste of time especially when I started I introduced the profit motive into my hobby. However, after some reasonable success with nmm on Cyclops and Colossus I decided that Iron Man would be a good learning experience.
The first step in learning to paint nmm was researching how metals and light interacted in the real world. If I couldn't imagine how the nmm should look like perhaps I could work it out from basic principles. The good news is that metals aren't some magical material but are rooted in the real world and behave in predicable ways. There are also many different types of surface that nmm could be considered appropriate such as brushed metals, chromes, and glossy plastics.
Using this knowledge I planned out a simple method of rendering the metal surface of Iron Man. For the light I decided a directed light source was preferable to ambient light and chose the sunlight zenithal construction. This meant there was only one factor in determining the amount of light on any surface, the angle of the surface to the light source.
To create the impression of metal I took inspiration from digital artists who paint the matte light and reflective light separately. This meant I would start by painting the shading and highlights as I would with any other material. The metal impression would come from the final bright highlights and exaggerated contrast.
I started as usual by basecoating the main areas of the model with pure red and deamonic yellow.
I then used very dilute chaotic red to map out the shading. The general idea is that any surfaces facing up are going to be highlighted and any surfaces facing down are going to be shaded with a transition occuring in between. Pretty simple but given the complexity of the shapes it's still worth taking this step slowly.
With the placement of the shading done I increased the contrast by applying more thin layers of the chaotic red.
With a mix of the red and a very small amount of white I highlighted the upper facing surfaces.
The armour plates were lined with a mix of chaotic red and black.
The contrast was increased further with a little more white. Turquoise was added to the shading.
A light pink mix was used to start the edge highlighting.
Black was added to the shading and white was used for edge highlighting.
Here's the red almost done. For that metallic resemblance it's important to keep pushing the contrast. I've also added a few specular reflection on the wrists and other spots to help create the form.
The finished model.
The result isn't entirely realistic but trying to incorporate, say, the light bouncing off the ground would make this a much harder exercise and I think this is a good start to painting nmm.