The backing material you use in a picture frame is just as important as the frame itself for the purposes of protection. A range of backing materials are available, and the quality of the material can determine the longevity of the frame.
Years ago, the standard backing for many photo frames was just a sheet of MDF (medium density fibreboard). Today, there’s far higher quality materials better suited to picture frames backing, providing the same lightweight finish while maintaining strength and rigidity throughout the frame. The problem MDF backing boards bring is the material is highly hygroscopic, meaning it’s going to attract and retain moisture. It’s, for this reason, it’s not a material that’ll last long because it is eventually going to warp. There are things you can do to slow down the degradation of MDF and the possible effects it can have on prints, such as lining the reverse side of prints with an acid-free paper barrier for moisture absorption or using a cotton rag or other 100% acid-free materials similar to the mount board. All this does with MDF backing is slows the degradation process down. It’s not something that’s going to last for decades.
A better alternative is using foam board or foam core, which offers the same strength and rigidity of MDF but with better moisture protection and it’s a lot easier to work with. It’s not as cheap, but it’s still affordable enough to be the go-to backing board of choice for a many a picture framer.
Backing Board Mounts
Just as the mount boards for picture frames are used to create a barrier between your artwork/photo preventing it from coming into direct contact with the glazing, the same materials can be used at the back of the print.
Using a backing board mount can prevent harmful chemicals from less suitable materials from coming into contact with the back of the photo or print. Two commonly used materials are foam boards and 100% cotton rag boards.
If you’re reframing an old photo, perhaps something you spotted in a charity shop, these quite often have MDF backing boards. To upgrade the backing material, you can either put a barrier between the MDF using a backing mount or switch the backing material to something more suitable. For a quick upgrade, you can do yourself; self-adhesive foamboards are easy to work with as it’s a dry mount technique that doesn’t require any specialist framing technique. Other types of foam boards won’t be pre-prepared and require a suitable adhesive application (wet mount). Another advantage of dry mounting your photo to foam board is there’s less chance of air bubbles forming between the two materials.
The last thing you’ll want to make sure you use on any backing board is the acid-free framing tape. It looks like the packing tape you’d see on parcels delivered to your home, but the adhesive should be 100% acid-free on framing tape to make sure it doesn’t degrade the effectiveness of the backing board. The thicknesses of tapes tend to be between 38mm and 75mm wide. The backing tape should provide an airtight seal to the frame, preventing moisture and dust accumulating.