Concept art introduction
Concept art is a pretty easy and straightforward job for when you need to put a concept given to you into a visual form. In that definition, there is no limitation in technique or software. So, sometimes you need a high-rendered concept, and other times you can use a simple dual-tone drawing. A good example of this is the Doom Hunter concept seen in the The Art of DOOM: Eternal by Dark Horse Books (2020). Another example is the Early Development section of The Art of The Dragon Prince by Dark Horse Books (2020).
You'll notice that the drawings are a completely different style from the final product, but you can see and read that the main point of those drawings was to put out ideas. This happens because there are various steps in the production stage, with different degrees of visualization of the final rendering. If you're at the early stages of production, some scribbling lines that give a general feeling will do the job. If you're making...