Reflections on Reflections

To create natural-looking reflections, we must understand what to look for. The best way to learn about natural reflections is to look at some.

For openers, we need an object and a reflecting surface. We can start with a white jug on a table. Compare these two images of the same jug on the same table.

Notice how a change in the camera angle produces a substantially different reflection. On the right, the jug's handle is visible, while it doesn't show in the image on the left. (In addition to the relationship among the object, the surface and the camera, the lighting is slightly different.)

Also take a look at the table just below the jug. With the lower camera angle (right), more of the underside of the jug is showing, areas that have to be created manually to produce a realistic reflection.

A third view of the jug and table illustrates another feature of reflections in nature. Take a close look at the lowest area of reflection on the table, the jug's spout. You'll see the irregularities of the table surface, emphasized by the low light source.

Because the light was close to the table top, the slight irregularities in the table's surface become much more noticeable. The light creates shadows and highlights that would not be seen if the light was directly above the table.

The texture of the tabletop is also visible in this next image, a reflection of a book.

Other than the texture, this reflection is reasonably simple to replicate. One flat surface is being reflected onto another flat surface. Compare that to the reflection of the round jug. First, take a look at the shape of the reflection.

Next, take a look at the line of reflection, the axis across which the subject is reflected. While there's a nice straight line to reflect the rectangular book, the jug's curved base provides a larger challenge.

The curved base of the jug represents a challenge. Rather than a nice straight line of reflection (red), the lower edge where it is in contact with the reflecting surface (the table), requires a curve. (You can think of it as a series of short straight lines of reflection.)

Likewise, when you can see two sides of a rectangular object, both in or near contact with the reflecting surface, you have multiple lines of reflection.

The corners are points that deserve attention when reflecting. In this example, the points where the subject is in contact with the reflecting surface are highlighted in red. Corners that are away from the surface are in yellow.

In addition, notice in the following figure that even in this simple reflection there's an area that's undefined in the original object. That part of the book's underside (indicated by the white dashed line) would have to be created to simulate a reflection. The area of concern is caused by corners and edges that are not in direct contact with the reflecting surface.

It's also important that a reflection follow the contours of the original object. Areas visible behind the original are not reflected, nor are surfaces away from the reflecting surface. The outline shows the part of the subject that should be reflected.

In addition to the upper surface of the top book, there's a bit of the lowest book that must be excluded from a reflection as well.

Another tricky consideration is reflections onto the subject. For example, the clasps on the toolbox in this image would reflect the surface upon which the toolbox is sitting. Those reflections (or a reasonable approximation) would have to be added to the clasps before the box as a whole is reflected.

Also keep in mind such things as candle flames and light bulbs. If visible in a reflection, they may need special attention to look like realistic light sources.