In which We Muse on the Nature of Nature

I keep getting asked how I *do* the reflections. There seems to be a common misapprehension that because I am forced to do quite a lot of retouching in PhotoShop that I am in fact manufacturing the reflections there.

Strictly speaking, this is not possible for a number of reasons, although I know many people do a quite credible job and no one seems to notice the difference.

But imagine holding a cup upside down over a mirror. (We're all more or less visually oriented people here, so I am not going to try to prove it with illustrations but if any of this is unclear go ahead and try it out literally.)

When you look down on the cup over the mirror you can see the bottom of the cup and the handle and presumably your hand holding it. And in the mirror you naturally see the inside of the cup and whatever part of the handle and your hand you can see is from a completely different angle.

So it should be pretty obvious that there's no way to manipulate the image of the bottom of the cup to give you an image of the inside.

Now hang the cup from a convenient string and start backing away. The further back you get, the smaller the angle between looking straight at it and looking at the reflection becomes, and the more similar the reflection becomes to a "flipped" version of the straight-on image.

Aha! That's it! We just have to portray the image as being far enough away so that the angles are too close to matter!

Well, yes and no. Consider a scene like the far side of a lake where we might want to create a rippled reflection which for some reason we don't already have in the picture. Because it's so far away, flipping each tree upside down and then wobbling the water a bit will be a reasonable rendering of the reflection. But as we come around the shore (which is not straight) the line which we need to reflect across curves down as it comes toward us. So simply grabbing the scene and flipping it vertically still doesn't work since the trees on the nearer side should not be flipped on the same line as the far shore (or their trunks will be partially missing). With a lot of continuous curved skewing (taking care that the verticals lines aren't bent over) you should be able to do it and then wobble the water for a nice effect.

But as far "creating" a closeup reflection of a model, you really can't synthesize it. In "The Waterbourne Girl" you can clearly see body parts (like her left hand) in the reflection that are not in the direct view. So there's no way to turn one into the other mechanically.

If you really need to create a realistic reflection just take two pictures while your model holds the pose: one directly and then a second, closer, looking down. Once you scale them to match you can warp the second one to get a believable image.

I think it's easier just to jump in the pool ...

Hopefully, you'll believe me now. If not I can't imagine anything else to say to convince you ...

-alberich