Have you ever admired a shadow box display and found your attention wandering from the contents to the edges, maybe leaning in to see how the glass and backing are so neatly separated? If so, this article is for you.
Spacers play a few important roles in picture framing, and are a necessary tool in any framer's shop. There are a number of different ways to create space in a picture frame, and we outline these processes below.
Spacers keep the glass or acrylic glazing separate from the artwork. This is important for a number of reasons. However, if a mat is being used between the glass and art, spacers are usually not necessary, unless the art has texture that may still come into contact with the glass, despite the mat. Spacers are also useful for forcing the glazing and artwork/backing to the front and back of the frame, if the frame is quite deep.
BUCKLING
As temperature and humidity in a room change, paper expands and contracts. Since glass is very good at transferring heat, artwork is in contact with the glazing will expand and contract easily, while sections not in contact (even only microscopically separate, due to the thickness of the media or natural curl in the paper) will do so more slowly. This causes imbalances across the face of the paper, and creates buckling, or waves.
By placing spacers between the paper and the glazing, heat is allowed to circulate evenly within the frame, distributing equal temperature changes to each section of the paper.
CONDENSATION
Condensation, or the formation of moisture on the inside of the picture glazing, can be caused when the temperature changes in the room, or when the artwork was not given proper time for "outgassing" - drying and releasing any gases or chemicals in the ink.
A properly framed picture should not develop condensation unless extreme temperature changes take place, but by using spacers to keep the glass away from the artwork, any moisture on the glass will remain there, and not damage the art.
ADHESION
Whether due to moisture within the frame, a slightly tacky media like some paints, or a collage with adhesive residue, there is a danger of the artwork sticking to the glass. Additionally, static cling can cause certain media such as pastel or charcoal to transfer from the artwork to the glass.
By inserting spacers to separate the glass completely from the artwork, no damage will befall the artwork, due to adhesion.
Creating a shadow box is one of the most practical times to use frame spacers. A shadow box frame is simply a regular picture frame with a deeper "rabbet" - the vertical drop behind the lip of the frame face. In regular frames, the rabbet is anywhere from 1/4" to 3/4" deep, to allow for various content thicknesses (content includes the glass, artwork, backing, mat, etc). A shadow box can have a rabbet of 1" or as much as a foot, for large, thick items such as memorabilia or clothing (wedding bouquets or dresses, baptism dresses, etc).
The spacer in a shadow box (sometimes called a "liner" since it will usually be visible from the front) must be wide enough to press the glass to the front of the rabbet, and hold the backing flush with the back of the frame. For example, if the shadow box has a depth of 1.5", the glass or acrylic glazing is 0.15", and the backing is 0.2", the spacer will be 1.15" wide (1.5 - 0.15 - 0.2 = 1.15). This allows 1.15" for filling with the contents of the frame.
The spacers produced by many companies do not make sizes large enough for shadow box frames. As a result, custom-made spacers are common for shadow boxes. The different materials used are outlined below.
Why paper artwork buckles
Media like pastels can transfer to the glass
Shadow box rabbet
HOW TO USE SPACERS
Frame spacers are adhered to the vertical edge of the picture frame rabbet. They may be narrow or thick, but cannot exceed the width of the frame lip, or else they will be visible from the front of the frame.
The spacer will usually be approximately the width of the Rabbet minus the Glass and the Backing. If, however, the entire rabbet space is not needed, the spacer can be smaller. This simply means the backing will be indented from the back of the frame instead of flush. Alternately, if more space is needed a larger spacer may be used and the backing may protrude a bit past the back of the frame. Stepped turn buttons can help in either of these instances.
The glass or acrylic must be in place before spacers are placed because once they are, there is no way to get the glass in. Some pre-made, store bought spacers are adhesive. They are cut to fit the length of the picture frame (multiple lengths can be butted against one another for very large frames), the backing is peeled off, and they are pressed in place behind the lip of the frame, forcing the glass against the lip. The backing is placed on top of the spacer and taped, glued or held by turn buttons.
There are different styles of frame spacers available.
Compiling the frame contents
SPACER STYLES
S-SHAPED
An s-shaped frame spacer - the most common are made by the company FrameSpace - holds the glass in the open curve of the "S". The closed curve provides the space, and the backing sits on the base. Larger depths have an additional vertical piece that holds the backing, and some may even have another open curve (resulting in an "E" shape) to hold the backing completely.
FrameSpace spacers are made from PH neutral plastic that will not cause discoloration or otherwise damage artwork. Unlike other spacers, because the plastic piece clips around the glass, no adhesive is necessary to hold it to the rabbet of the frame.
This clip can be useful for metal frames, as it keeps the glass from chipping against the metal. The downside of this spacer style is that the size must match not only the depth of the rabbet, but also the thickness of the glass so it is held firmly in place. Spacers for thinner and thicker glass or acrylic are available.
Framespace spacers are all 3/16" wide, which allows them to be concealed behind most frame lips. They come in the following depths:
1/8" (only available in clear and black)
3/16"
1/4" (also available in the double "E" shape, clear color only)
A simpler spacer style is the rectangular, hollow tube shape. EconoSpace is the most common brand to make this style - they are called "Art-Glass Separators". Like FrameSpace spacers, they are made from PH neutral plastic that will not harm the artwork. These spacers are adhesive on one side, and can be stuck to either the backing board or the glass. This allows them to offer two finish options for the visible portion - one on each side: glossy, and matte. Depending on the frame and the artwork, one finish will be exposed, while the other will be hidden against the frame rabbet.
EconoSpace spacers are also 3/16" wide. They come in four different depths (called "airspace):
1/16" (solid plastic, not hollow)
1/8"
1/4"
3/8"
CUSTOM MADE
Sometimes the space required between the glass and the backing is not a standard measurement and a pre-made spacer will not be suitable - for instance, a deep shadow box. In this case, a custom spacer can be designed.
An ideal material for custom spacers is foam board, because it is thick enough to support the weight of the glass, but thin enough to stay hidden behind most frame lip (approx. 1/4"). The foam board can be cut to any depth necessary, from a narrow 1/4" space to many inches. It can be glued to the frame rabbet or affixed with double-sided tape. Foam board with an adhesive backing (pictured right) is also available, and can eliminate part of that step.
For specialty colored spacers, matboard may be another option. Mats are generally quite thin, however, and can allow the glass to slide down if it is even a little smaller than the frame dimensions.
As mentioned above, many pre-made spacers are PH neutral, which means they will not damage the artwork or any of the frame contents over time. If a custom spacer is made, however, and archival quality is required, the spacer should be cut from acid-free foam board or museum-grade matboard.
COLOR
The color of the spacer should always match the artwork/backing of the frame. In cases where the artwork is many colors, the choice is the artist's: black will created a shadowed effect, while white will let light into the corners of the frame. If a specific color is needed, matboard or paper can be used to line the spacer, though this requires more work on the part of the framer, and extra cost should be assumed.
Spacers made by EconoSpace and FrameSpace come in white, black, and clear.
SIZE
The length of the spacer is not the primary factor, since multiple lengths can be laid along the rabbet if the frame is very large.
Both FrameSpace and EconoSpace spacers come in 5-foot lengths.
Foam board for custom spacers may be limited by the maximum width of the cutter.
PRICE
Spacers are generally quite inexpensive, though they are often available only in large quantities. If you are putting together a custom frame yourself, consider speaking to local framing shops, who may be able to sell spacers to you in smaller amounts.
Both FrameSpace and EconoSpace costs between $35 and $45 for 12-5 foot lengths (60 feet).
A frame with glazing and spacers
If you are framing artwork without a mat, then spacers are an essential tool. They are simple to use, and can make all the difference in the longevity and appearance of your artwork.
At KeenART Media, we use both plastic and custom-made spacers. If you have any questions about our framing procedures, or any of our products or services, please do not hesitate to contact us.
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