What is the Difference Between Glass and Acrylic?
Framing artwork involves more than just a frame and a couple of nails. It also involves the framing glass, which doesn’t always necessarily have to be glass — it can be acrylic, too! Choosing the framing material is an important consideration as it can both protect the artwork and allow you to view the piece unhindered (or hindered, depending on which you choose). There are many different types, all offering their own benefits: specially made glass can feature
anti-reflective properties
or
UV protection.
Similarly, acrylic can be made with UV filters or non-glare properties. However, each glazing material has its drawbacks. Glass can easily shatter and it is heavy; acrylic, on the other hand, can build up static and is easily scratched, so care must be taken when cleaning. Whichever framing material you choose, it is best to weigh all options — and ask yourself the right questions — before making a decision.
How Light Affects Artwork
When you frame a piece of artwork or a photograph, you expect to see the image as it is—but this is often not the case, as the framing glass that protects the artwork can also distort and dull it. We actually never see framed art as it truly is because, when using regular clear glass, what we actually see is the light that is reflected from it. Of the incoming light passing through the glass, 2 percent is absorbed by the glass and 8 percent is reflected away from it, which results in glare. For outgoing light, the same is true; this means that we retain only 80 percent of the image’s clarity when using clear glass to frame a photo or artwork. Using specially made art glass, however, these effects can be greatly reduced. Art glass, with its non-organic materials and low-iron properties, does not distort colors. Using art glass will also result in a 99 percent illuminated image and less than 1 percent glare, allowing you to enjoy your artwork the way it was meant to be seen—in full clarity.
Glass vs. Acrylic
Choosing the framing material is an important consideration as it can both protect the artwork and allow you to view the piece unhindered. There are many different types of glass and acrylic frame glazing, all offering their own benefits. Specially made glass can feature anti-reflective properties or UV protection; similarly, acrylic can be made with UV filters or non-glare properties. However, each glazing material has its drawbacks. Glass can easily shatter and it is heavy; acrylic, on the other hand, can build up static and is easily scratched, so care must be taken when cleaning. Whichever framing material you choose, it is best to weigh all options—and ask yourself the right questions—before making a decision.
Using Acrylic Glazing for Picture Framing
Acrylic is a lighter-weight, shatter-resistant alternative to glass frame glazing. (Glazing is the generic term for the glass or acrylic used to cover and protect the image.) Acrylic glazing comes in a variety of finishes to protect your framed art and photos and is ideal for large framing projects. Acrylic is prone to scratching, however, and requires careful handling when framing and cleaning.
Acrylic Choices for Picture Frames
Standard Acrylic
Standard acrylic has no coatings, no matte finish, and no tint. It is translucent and optically pure. Acrylic is more optically pure than glass except for the very expensive low iron glass sometimes referred to as Water White. Regular glass has a green tint, which is readily visible if you place a piece of glass on white printer paper. Standard acrylic is probably fine if your print is standard photographic print process or archival inkjet, if you do not need it to last past 10 years, or if you are not displaying it in direct sunlight. If the print is a standard inkjet print and it's not being sold, then standard acrylic should be fine because the image can be reprinted.
UV Filter Acrylic
UV filter acrylic blocks up to 99% of Ultraviolet (UV) radiation. This helps reduce fading on all types of photos in picture frames. UV filter acrylic has a slight yellow tint which can create a minor warming effect. Slight tint means that it has approximately half the tint of glass. If you do not notice the green tint on the picture frames in your house, you will not notice the yellow tint in UV filter acrylic. Consider UV filter acrylic if you will be displaying your photo frame in a brightly lit room, or if you need the photograph to last past 10 years. (Note: 10 years is a conservative number.) Standard photographs can last longer than 10 years with very little fading depending on the type of light in which they are displayed. It also depends on how much fading you can tolerate. A photograph can still fade with UV filter acrylic unless it's kept in darkness.
Non-Glare Acrylic
Non-glare acrylic has a matte finish on one side to reduce the glare from light. Some non-glare acrylic will cause a noticeable loss of sharpness even if it is against the print. This high quality product causes only a minute loss in sharpness, even with a thick 8-ply mat. With 4-ply mat you will need a loupe to detect the loss of sharpness. This version of non-glare does not have any UV-filtering making it optically pure (no tint). Non-glare will not completely eliminate the glare of light, but will reduce it considerably and make the picture frame much more presentable in poor lighting conditions. The drawbacks are higher cost and a possible slight loss of sharpness. The best way to display an image is with standard or UV acrylic and proper lighting so that no glare is created.
UV/Non-glare acrylic is a combination of UV-filter and matte finish to block UV rays and reduce glare.
Acrylic Cleaning and Static Removal
We tested several acrylic cleaning products for ease of use and static removal ability. The clear winner for cleaning picture frame acrylic was Brillianize, a one-step cleaner and polish for acrylic. During testing, Brillianize acrylic cleaner and polish appeared to actually increase the sharpness of the image under the acrylic by a minute amount. We suspect this was because it helped remove some leftover residue left from the protective paper mask. Brillianize cleaner and polish significantly reduces static charge on the acrylic. Another way to reduce the static charge is by wiping the acrylic down with a damp cloth while it still has the paper mask covering. This a great method if you are in a hurry to get the frame assembled, but don't want all the dust in the room to be pulled onto the acrylic.
Do not use paper towels to clean acrylic. Paper towels are the equivalent of wadded, ground-up twigs. Micro fiber cloths, however, work very well. After considerable research, we found the equivalent of a micro fiber chamois, which is our favorite. This cloth is manufactured (or resold) by Craftics and they call it "Microfiber Smooth Towel". It quickly removes that last cleaning streak off of smooth surfaces.
Acrylic Paper Mask Removal
Acrylic comes with a mask over the acrylic to protect it from scratches. The masking material can be either plastic film (easier to remove) or paper (more difficult to remove). The plastic generally protects just as well or better than the paper but is easier to remove. The acrylic mask needs to be removed when you are ready to hang your photo frame.
To remove the plastic mask material, simply peel back a corner and peel off the plastic.
Follow these steps to remove a paper mask:
- Get a cardboard tube such as those used for mailing posters or large photographs
- Center the tube over one corner of the acrylic sheet
- Peel the corner of the paper up and press it against the tube
- Use the tube to roll the paper mask off the acrylic sheet
Removing Stubborn Backing
All acrylic maskings become more difficult to remove over time. When exposed to heat or sunlight, the masking becomes more difficult to remove. Acrylic should be stored in a cool, dry place, and maskings should be removed within two years.
Sometimes the top layer of paper comes off leaving a hard to remove second layer attached to the adhesive and acrylic. When you experience problems removing paper masking on the sheet, it is because the adhesive dries up. This usually happens because of storage conditions and/or the age of the sheet. In order to dissolve the adhesive, kerosene, hexane, or aliphatic naphtha can be used. Kerosene is probably the easiest solvent to find. You can find it at your local hardware store. A power washer can be effective in removing the film covering.
Acrylic vs. Glass for Framing
Acrylic and glass both have advantages and disadvantages for picture framing. When deciding which type of glazing to use for a framing application review the following list of questions and then see our discussion about the pros and cons of both acrylic and glass.
- Where will the picture frame be displayed?
- How large is the picture frame?
- How often will it be moved?
- Who will clean it?
- Is the artwork replaceable?
- Will the picture frame be shipped?
Acrylic Pros
Lightweight - acrylic is lightweight, making it easier to transport than glass. It is the preferred glazing for large picture frames because the weight of glass can be problematic for the frame's moulding, hanging hardware, and even the wall itself.
Shatter Resistant - acrylic is the ideal glazing to use if you are shipping your artwork; especially pieces in larger picture frames. Very safe for picture frames in high activity areas such as children's rooms or recreational areas. Some art galleries insist that the artwork be framed in gallery picture frames with acrylic for liability reasons, and many museums utilize acrylic because broken glass can permanently destroy rare artwork.
Optically Pure - acrylic is more optically pure than glass with the exception of expensive reduced iron glass such as Tru Vue Museum glass. Regular glass, especially less expensive non-framing grade glass, has a green tint. UV filter acrylic and UV filter glass both have a yellow tint (including the Museum glass). The yellow tint is due to the UV filter and it may create a slight warming effect. In the case of acrylic it is built into the material. In the case of glass, it is coating that may deteriorate and lose effectiveness depending on the quality of the brand.
Insulating - acrylic is a better thermal insulator, so condensation is less likely to occur inside the frame.
Acrylic Cons
Expensive - glass and acrylic have several different quality levels. Standard acrylic typically costs more than standard glass. Glass with reduced iron, UV-filtration, and anti-reflective technology will cost more and perform better optically than acrylic with UV-filtration and non-glare technology. Acrylic with UV-filtration, anti-reflection, and abrasion resistance will cost even more than that glass.
Lack of scratch resistance - with the exception of expensive abrasion resistant versions, acrylic is more sensitive to scratching than glass and requires special care. Only soft cloths, such as microfiber cleaning cloths, should be used to clean it. Paper towels are essentially ground up wood pulp and can damage acrylic. If you are reselling framed artwork with acrylic as the glazing, educate your customers about the proper way to clean it.
Susceptible to bowing - acrylic is more flexible than glass and larger sheets can bend or bow depending on the thickness, temperature and humidity. In general, however, this is not an issue for smaller pieces. Must be stored properly.
Static charge - acrylic is susceptible to higher levels of static charge than glass, and for this reason it should not be used to frame chalk pastels. The static charge can be a nuisance during frame assembly since it will attract dust into the frame. Products such Brillianize as and other static removal tools are very effective at neutralizing static charge.
Removal of protective paper/film - acrylic is sold with a protective paper or film coating that must be removed during the final frame assembly. The film is easy to remove, but provides little protection resulting in the possibility of increased scratching during processing and handing. Paper provides very good protection, but is much more difficult to remove.
Glass Pros
Less expensive - while there are many different quality levels of glass and acrylic, overall glass is typically less expensive than acrylic.
Scratch resistance - standard uncoated glass is very scratch resistant and therefore does not require special care like acrylic. It is also resistant to solvents. If you are reselling framed artwork, you do not have to educate your customer about the proper care of glass.
Less static charge - static charges will attract dust into the framing package. Normally, glass will not build up static charges like acrylic glazing.
Does not bow - glass is very stiff and will not bow, and does not respond to changes in relative humidity.
No protective covering to remove - glass does not require a special protective coating. Final frame assembly only requires cleaning the glass.
Glass Cons
Heavy - glass weighs considerably more than acrylic resulting in increased shipping costs. In addition, using glass as the glazing may require stronger and larger frame moulding and/or braces, and heavy duty picture frame hanging hardware.
Easily broken - glass must be transported carefully and it has a much greater potential for damage during shipping than acrylic. Buying glass locally will eliminate shipping damage issues.
Not optically pure - the iron content of standard glass creates a green tint. This tint reduces the light levels and creates a green tint on the artwork. Glass is available with reduced iron content making it much more optically pure. This type of glass will often have a UV-filter causing it to have a slight yellow tint. It will also cost more than most types of acrylic.
