HOW VENEER IS MADE

There are a few different methods used to slice veneer from large flitches (a flitch is the section of a log which is prepared for slicing). Each method produces a different look to the veneer.

Rotary Sliced Veneer

For rotary sliced veneer, the whole log is mounted on a rotary lathe and spun. The blade slices a continuous sheet of veneer from around the entire circumference of the log. This is the least wasteful, most economical method of producing veneer, but it is generally not the method of choice where grain-matching is desired from sheet to sheet.

Typical "erratic" grain pattern of rotary sliced oak veneer.
Picture courtesy of veneernet.com.

Plain Sliced (or Flat Sliced) Veneer

For plain sliced veneer, the log is de-barked, cut in half and mounted on a slicing table, which moves it into the blade taking progessive slices out of the flitch. This method tends to produce the common cathedral grain pattern, in consective leaves of veneer which can be grain matched in various ways for a pleasing appearance.

Typical "cathedral" grain pattern of plain-sliced, flat-sliced or halfround-sliced oak veneer.
Picture courtesy of veneernet.com.

Quarter Sliced Veneer

In order to get veneer leaves with straight grain rather than cathedraling, veneer is often quarter-sliced. The log is ripped into four quarters which make up four separate flitches. Each flitch is sliced in the direction shown in the photo below, which produces a very straight grain pattern. Quater slicing also reveals figuring in some woods that contain distinct medullary rays. This method will produce the "flaking" or "ribbon" effect common to oak, and the curly effect in many species of wood.

Typical straight grain pattern (with "ribbons") of quarter sliced oak veneer.
Picture courtesy of veneernet.com.

Rift Sliced Veneer

Rift-slicing is done on quartered flitches, like quarter-slicing. The difference is that the quarters are turned in a lathe to produce an approximate 15 degree cut. The purpose of this is to minimize the "flake" appearance which is common to quarter-sliced oak due to medullary rays. (Personally, I like the ribbons.)

Typical straight grain pattern (without "ribbons") of rift sliced oak veneer.
Picture courtesy of veneernet.com.

Half-Round Sliced Veneer

Finally, the half-round slicing method is similar to the plain-sliced. The difference is that the log-half flitch is sliced in a cresent pattern, which produces an appearance similar to plain-slicing, but increases the width of the veneer leaves.

Picture courtesy of veneernet.com.

TIGHT SIDE AND LOOSE SIDE

There are two faces to each sheet of veneer, and on each sheet one face will be the "loose" side, and the other will be the "tight" side.

When you bend a sheet of veneer with the grain, it will bend further and more easily on the loose side than on the tight side.

The difference between each side is caused by the action of the veneer slicing blade upon the cells of the wood. The blade tends to open up and tear the cells on the loose side, while closing and compressing the cells on the tight side.

Veneer tends to absorb stain and retain more pigments on the loose side than on the tight side. A bookmatched veneer panel will consist of veneers showing tight side up and veneers showing loose side up, so portions of bookmatched panels tend to stain up darker than other portions.

What causes a tight side and loose side on veneer?

In the picture at right, the blade is seen slicing a rotary cut veneer. As the sheet peels away, the outside curls up and the cells on that side are compressed. The inside face curls out, and the blade tears at the cells while the motion away from the log or flitch causes the cells to open up and become loose.

CELL POLARIZATION

In addition to the difference in appearance of tight and loose sides of veneer, there is often a polarization of the cells that becomes apparent when wood is viewed from different angles. From one angle, it will appear dark, from the opposite angle, it will appear light. With bookmatched veneer panels, as in the image at left, one side of the bookmatch will often reflect light differently from the other side, again causing a light/dark contrast due to polarization of the cells.

Sound complicated? It's really not. This page from veneernet.com has a picture that can help you understand cell polarization in veneer. You can also reach that page by clicking on any one of the three photos above.