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There's been lots of interest lately in creating
images of objects sitting on highly-reflective surfaces. This
column will take a look at a few general principles to keep in
mind when creating reflections.
The primary concept to remember is "realism." If
the reflection doesn't behave as it would in nature, it will
stick out. The viewer may not know what is wrong, but it will be
obvious that something is wrong.
Two problems that you may notice are rotating
rather than flipping a reflection across an axis, and reflecting
the wrong side of an object. In this image, the letters have
been flipped across the line of reflection correctly.
In this image, the copy of the letters has been
rotated rather than flipped.
In the next example, the reflection is at a
strange angle, but that's not the real problem. When you analyze
the image you'll see that the wrong side of the calculator has
been reflected. Since the shiny surface is behind the
calculator, the back of the object should be reflected. When
this problem occurs with peoples' heads, it appears as if a
ghost is looking out from the mirror or window or other
reflective surface.
The need to reflect the "back" of an image
occurs when the reflective surface is placed behind the subject.
Since Photoshop is a 2D image editor, there usually isn't a
"back." In the following example, a second image (from the same
source as the first) is used to form the reflection.
The same pair of images can be reversed (and
rotated and scaled) to present another view:
Another important part of natural-looking
reflections is the angle. In a simplification, think of the
position of the reflection as the product of three points in
space: the original, the reflecting surface, and the viewer's
point of view. While the appearance of a reflection is affected
by the position of a light source, the position of the
reflection itself is not.
The angle of the reflecting surface determines
the angle of the reflection. Try this: Hold a mirror in one
hand. With the other hand, place the point of a pencil directly
on the surface. Rotate the mirror (keeping the pencil vertical)
and watch the change in reflected angle.
Another trap to avoid is not matching the
reflecting surface. In this example, exaggerated ripples have
been added to simulate water flowing along a street. Compare the
reflections.
In the next installment of this series, we'll
look at some basic reflection techniques. |