Here is a list of some key archival methods. I am sure there are some not included, but these are the main, most important ones. Please feel free to add other ones if you think I’ve missed any.
Before reading on….its important to note that it is not necessary to do every single one of these archival procedures. Adding any one of them will add longevity to your work. Feel free to select only those that work for you and your art.
(1) Selecting a Substrate or Surface:
Use a rigid and sturdy painting surface. A panel isn’t as flexible as canvas on stretchers, so with less movement, there’s less chance of cracking. There are many great commercial panels on the market. I like to use Ampersand’s Hardbord (http://www.ampersandart.com), but they have many other types available. I also use a local cabinet maker to create customized panels when I work large or need an unusual size. I still enjoy working on stretched canvas, but I find the panels are a joy to work with.
(2) Stain Sealing & Priming:
Before priming, there is an important step called “stain sealing”. Stain sealing is not necessary for oil painters, but is essential for acrylic painters, especially anyone working thickly or in several layers. Start with an unprimed surface if possible.
(*If it is already primed, then the primer is usually of cheaper quality – OK for oil painters – but not OK for acrylic painters. The cheap gessos can create adhesion problems later. Lets say months after your painting is finished, you send the painting to Florida where its moist and hot, then it goes to a cold climate, then back again. Your adhesion layer, or primer, is what keeps the paint sticking to the surface during all the fluctuations that happen, and if its of bad quality, your painting could flake and peel off.)
Stain sealing keeps any impurities from being absorbed into your acrylic painting layers. These impurities can create stains or cause your paint to yellow. The more thickly acrylic is applied, the more likely it is to pull any impurities up through the support and into the paint layers. There are two choices of products to use for stain sealing. Commercial stain blockers such as Kilz, are available at paint, hardware and home improvement stores. Kilz, similar to most commercial stain blockers, is formulated for walls and other rigid supports and should not be used on any flexible artist’s support, such as canvas. Golden has a stain blocker called GAC 100 which is specially formulated for fine art work, and can be used on canvas and other flexible surfaces. GAC 100 will work well on any surface and would be the more archival choice.
There are many reasons to prime your support. Oil painters need to prime canvas and other supports to keep the oil paint from destroying the natural fibers in those surfaces. Acrylic paint, though, is safe to use on most supports and can be painted directly without primers. Priming for acrylic painters is still recommended, though, for other archival reasons. Priming will increase adhesion, or the bonding of paint to support. Priming, then can make your painting last longer and ensure its stability. If your painting gets caught in a flooded storage area, or ends up moving frequently to different climate zones, the primer will strengthen the bond between painting and support, reducing cracking and other possible defects that can occur.
There are reasons you may not want to prime. For instance, let’s say you are painting over a beautifully patterned piece of fabric. You wouldn’t want to prime, or you would be covering over the pattern with the white primer (and clear primers aren’t a valid substitute – in my opinion).
(3) Using Light-Fast Pigments:
Select paints with a higher lightfast rating. The lightfast rating for each paint is often listed on the product label. This lightfast system was developed by the American Society for Testing and Materials (ASTM). If the rating is I (Excellent) this paint will be a great choice for outdoor murals and other archival painting needs. A lightfast rating of II (Very Good) means this paint should last for over 100 years and is therefore well suited for archival painting needs. Paints with a lightfast rating of III or more should be avoided in a painting, unless longevity is not desired. If you are working on a mural outdoors, then this is an important factor. When selecting the colors you will use on this mural, you can easily pick the most light-fast ones by using the charts available.
(4) Using Professional Products:
Cheaper products have filler and low quality ingredients. That means they may not look the same even a year after your work is complete. As an example, home improvement products, like paints from Home Depot or other home improvement stores, sell acrylic or latex paint that is much cheaper then fine art products. All paints are made of pigment (for the color) and binder (makes it into paint). So even though Home Depot paint is acrylic, the manufacturers know you will be painting on a rigid surface, and only need it to last about 5 years, whereupon your house wall gets repainted. Yellowing, flexibility and longevity are not factors for commercial paint manufacturers. By selecting professional “fine art” quality products you are adding a great benefit to the longevity of your work.
(5) Varnishing with UV Protection:
It is important to know about varnishing, as it is one of the best ways to protect a painting. It is also the only way to insure that the painting can be cleaned later. This is true for oil paintings as well as acrylic. First of all, due to environmental factors, paintings on any surface will expand and contract over time. Acrylic will soften in warm temperatures and stiffen in cold. This amount of movement will not crack or otherwise harm the painting, however, it will encourage the collection of dust on the painting’s surface to merge into the top layer of paint. The dust dirties the painting causing yellowing and haziness. The dust cannot be removed from this top layer of paint. An archival varnish, one that is appropriate for fine art paintings, is non-yellowing and removable. When applied as a final layer over a painting, this clear removable finish will collect the dust and being removable, offers a way to clean the painting. To professionally clean a painting in a museum, conservators remove the old varnish and apply a new coat.
Avoid using a varnish from a commercial paint store (generally formulated for household use like wood porches and patio furniture) which is not removable and will yellow over time. Using this type of varnish will ruin your work of art and you will not be able to remove it. Be wary of acrylic products labeled “varnish and medium” on the same container. A medium is permanent and a varnish is removable, so it is impossible for one product to be both. The paint companies that make these products are using the term varnish loosely for a craft market to mean “sheen”. Check the product label to see if there are any instructions on removing the varnish. If there are none, then this is not an archival varnish.
Damar Varnish, which is produced by many paint companies is a traditional varnish which can be used on oil or acrylic paintings. Damar tends to yellow slightly and is only available as a gloss sheen, but is removable, so it is a good choice. I prefer to use Golden’s varnishe
s, as they offer several advantages over Damar. They are available in varying sheens such as gloss, matte and satin; and have UV protection which will help protect the paintings from fading due to light exposure, making them a great choice for outdoor murals. The UV protection also makes these varnishes a good choice for ink jet prints which fade quicker due to the inks used. They will not yellow or crack.
Varnishing can be very easy and it can also get quite complex. Visit Golden’s website at www.goldenpaints.com for a great detailed instruction sheet on varnishing with lots of how-to details. I recommend reading this information before starting to varnish. I also recommend experimenting and testing on scrap work before trying it out on an important finished painting. Varnish should be applied over a non-absorbent surface. Applying an isolation coat on your finished painting before applying a varnish will insure that the finished surface is non-absorbent.
(6) Care & Storage
To properly care for your acrylic paintings after they are completed it is important to understanding the paint’s drying process. Acrylic is “dry to the touch” when the top layer of the paint skin has dried, but the acrylic is not completely cured until the entire thickness of the paint layer is dry. This may take several days to several weeks depending on the layer’s thickness and environmental factors. Until the painting is fully cured, waiting at least two weeks to be sure, do not wrap it up too tightly or store the work in a closed environment. In addition, especially during this curing phase, do not expose the painting to extreme temperatures below 35 degrees Fahrenheit. If your painting freezes during this curing phase it may never recover enough for the paint to form a strong paint film and bond. Even after this curing phase there are still some considerations to handling an acrylic painting. When wrapping your painting, be sure that you use smooth wrapping materials. As mentioned earlier acrylic paintings will soften in hot temperatures and stiffen in cold. Let’s say you use bubble wrap with the bubble side of the wrap in direct contact with the painting’s surface. If it gets hot while in transport the acrylic may soften and take on the impression of the bubbles. When the painting gets hot and softens it also may stick to other surfaces with which it comes into contact. Use a non-stick plastic such as HDPE in contact with the painting’s surface. When the painting surface is glossy it has more of a tendency to get tacky in hot weather and stick. Be kind to your paintings, they are worth it. Occasionally wipe the painting off with a damp cloth to remove dust and any other elements which may come through to the upper surface long after the painting is cured.