Anatomy of a frame-and-panel door
Pattern, highlights and shadows are at the core of furniture design, and all three are on display with a frame-and-panel door. Wherever the flat surface gives way to change in height or form, a line is made. However slight that change from flat may be, it produces a shadow or a highlight. And it's from the highlights and shadows that we comprehend shapes.
Which design would you choose? In the three examples above, only the frame dimension is changed; the other elements are left unaltered.
Variations on a theme
From top: a beaded panel, a handmade raised and-fielded panel and a plant-on frame-and-panel.
Frame-and-panel construction affords opportunities for great variety. Details, from the arched top rail shown at left to the subtle mitered corners on the shoulder line (right), can be tailored to situations calling for particular design elements.

Let's begin with the reason we use the frame-and-panel. It's a time-honored solution to the fact that solid wood shrinks and expands across the grain as it responds to changes in the amount of moisture in the air. By making a strong frame out of narrow pieces of wood and allowing the wide panel to "float" in a groove inside the frame, the panel is free to expand and contract. In some variations, a broad, beveled edge — called the field — disguises the  movement and thins the panel to fit its groove. With the innovation of frame-and-panel construction, any sort of furniture from chests to chairs could be made with reasonable expectation that they would survive the stress of seasonal wood movement.

This system is very old, and people are comfortable with how it looks — so comfortable that when we make doors of plywood or MDF, materials that don't shrink or expand, we often rout out shapes that imitate solid wood frames with panels.

Pattern, highlights and shadows are at the core of furniture design, and all three are on display with a frame-and-panel door. Wherever the flat surface gives way to change in height or form, a line is made. However slight that change from flat may be, it produces a shadow or a highlight, depending on where the light is coming from.

And that matters because it's from the highlights and shadows that we understand the shapes of anything that we are looking at.

Those visual changes come from the interplay of the four elements of a raised frame-and-panel: the frame; the groove; the slope; and the center field. How the elements relate to one another is an important concern. Do they sit comfortably together? Is any element too big or too small? What changes would make the panel more dramatic or attractive? How would a double bead on the inside of the frame look? How would a rise between slope and center field look? You can, of course, change any or all of the elements. Any change affects the whole.

This relationship between parts is called proportion, another key element of furniture design. The proportion of part to part and part to whole only gets more complex. So as we concern ourselves with the technicalities of making the frame-and-panel —which joint, which cutter — it's important to realize that our decisions have a direct bearing on the aesthetic outcome. For example, if you make a door with a cope-and-stick router bit set plus a panel raising bit, the bit set creates a joint to hold the frame together, makes matching grooves for the panel and molds the inside edge of the frame. The companion panel raising bit forms the field and the tongue that fits the groove in the frame and might mold the raised portion of the panel. The upside is that this tooling gets the whole job done. The downside is that you can't adjust anything, no matter the size of the door.

The simplest form of frame-and-panel is a single panel sitting inside a frame — the sort of thing you see on the typical kitchen cabinet door. But the system can be designed to be much more complex by the use of vertical and horizontal frame members inside the frame with many panels. Panels put together to form a box can be used to make casegoods — cabinets, storage furniture, and so on. These simple elements can quickly get very complex.