What is a "shadow line"

Question

I saw a reference to a "shadow line" in the context of making a tiny rebate (rabbet for US speakers) in the top part of the bottom half (i.e. not the lid) of a decorative box.

What is a shadow line?

Answer 1

Keshlam said it well, but I want to add a few thoughts.

Shades and shadows are an important design consideration in any three dimensional work of art (and any woodworking project is art as well). Shadow lines can emphasize or hide a feature. Since they are created by the lighting of the work piece the importance of the lines can change according to the direction and intensity of light. A simple wooden box displayed in the sunlight will change in character depending upon the time of day and direction of the sun. A projection or recess near the top edge of the box can emphasize the lid. Place the shadow line near the bottom and it may de-emphasize the box base and give the body of the box the appearance of floating above the table surface.

The shadow line may be applied to appear thick or thin, horizontal, vertical, or any angles (or curves) desired. It can be continuous or dashed. Sometimes it is not even a real shadow as when inlaid contrasting woods are used to create the affect of a shadow for a 3D appearance. After completing a woodcraft project I often try lighting it from various positions to see the impact the shadows have on appearance. It may be too late for the current one, but there is always a next time!

Answer 2

A shadow line is exactly that -- a line of shadow created by the shaping/alignment detail of the woodwork. It makes the object more 3-dimensional, and more interesting to look at, than a flat surface would be. You can think of it as the simplest kind of decorative carving.

If the plans you are looking at include a photo, you should be able to see this line in the picture. Consider what the piece would look like without that line across it.

The difference is sometimes subtle, and whether it's an improvement is always a matter of opinion -- but every element of design is a matter of opinion and many are subtle.