What techniques will help me paint a convincing desert mirage?
Adnan Nordström, Sweden
Answer Tony replies
Not until getting this question did it ever occur to me how strange painting a mirage is. Technically, a mirage is an optical illusion that occurs when light rays bend while taking the path of least resistance around a pocket of hot air. To us, it creates a reflection just above ground that looks almost exactly like a body of water.
First point in capturing the illusion is making sure you’re painting the mirage over a flat stretch of land. It generally doesn’t travel up or down hills, so drawing it that way can undercut the fidelity. Next, make sure that the mirage reflects the things located just above it. You can actually paint the horizon on a separate layer, duplicate it and flip the whole thing vertically to save a little time.
Since you want to differentiate this from a lake, though, I suggest softening the edges located around and directly above the mirage, to imply the heat distortion. Sometimes they have pretty sharp edges, but the more clean your borders are the less obvious it is that it’s not just still water.
That being said, there’s one thing I’ve found that I think reinforces the fact that it’s a mirage. Sometimes, if the mirage is right on the horizon line it can obfuscate big chunks of it. Because the heat is bending the light from the horizon, it makes everything sitting above it appear to be free floating. Since this phenomena rarely occurs otherwise, it helps sell the narrative.
The tough part is trying to paint a mirage in a way that isn’t exactly the same as painting a lake in the same spot That mirror-like feeling is important, so make sure you play it up.