So, you’re ready to return to the studio after a long hiatus, but what’s the condition of the supplies you left behind? One of the first things you should do after taking a long time away from art is taking a look at your materials to find out what’s still good and what needs replacing.
Some materials, especially dry media, are exceptionally stable and can last indefinitely. Wet media, particularly water-based, are more vulnerable. Anything that oxidizes, reacts chemically, or which depends on preservatives for stability should be looked at first.
Oil Paints: When tightly capped with no punctures in the tube, oil paints can remain usable for many years, often decades. Exposure to air is the main factor in degradation, because oil paints dry by oxidation, and it doesn’t take much to start the process. Even pigments with lower lightfastness typically don;t fad in storage because light is excluded. If the paint has a normal, soft appearance and isn’t unnaturally stiff or pasty, it shoulf be fine to use.
Acrylic Paints: Under the best conditions- tightly capped, uncontaminated, and stored in moderate room temperature, acrylics can last 5-10 years or more. However, if foreign material is in the jar, or if preservatives lose potency, mold can develop. Surface colonies of mold can be removed (make sure not to mixing it into the paint) and the rest can be used up right away. Acrylic paint that has a separated or clotted appearance should be thrown away.
Watercolor and Gouache: These paints, whether in pans or tubes, have a long shelf life (10+ years) under ideal conditions. Tubes need to be tightly capped to prevent drying and loss of preservatives. Pans should be clean and dry before storing to avoid mold growth. Dried out pans and even dry tube colors can still be reconstituted, but moldy watercolor pans and cakes should be discarded.
Solvent-Based Varnishes and Oil Painting Mediums: Synthetic solvent-based varnishes that remain liquid with a clear appearance can generally be used indefinitely, but damar varnish made with turpentine (and pure gum spirits of turpentine itself) can diminish in quality and turn brown in storage. Don’t use turpentine or damar varnish that has turned color. Linseed oil and Stand Oil that is still fluid and hasn’t skinned over should be fine. Same with alkyd mediums, but be prepared, because alkyd that’s been opened will almost always form a thick skin and will need to be replaced.
Graphite and Colored Pencils: These are exceptionally stable. Graphite is practically immortal, and the binders in colored pencils are very durable. They can last indefinitely under ideal storage conditions, barring breakage.
Charcoals and Pastels: Vine and compressed charcoal are unaffected by age, heat, and light, and unless they are broken or get wet, expect them to be in the same good condition they were last time you used them. High-quality soft pastels made from light-fast pigments are similarly durable. Hard chalk pastels might not prove as light-fast, so check any exposed surfaces for fading.
Drawing inks can vary in shelf life, so this is one category that might need replacing. Carbon pigmented India ink will retain its dark color indefinitely, but dry particles and binder coagulation can make them unusable, and they can grow mold. Colored inks may be fade prone, especially if exposed to direct sun.
Acid-free, archival papers made from buffered alpha pulp have a long storage life, and those made from cotton or linen rag can last for centuries, under ideal conditions. Papers with high lignin content like newsprint, manila, and scholastic-grade sulfite paper degrade rapidly, yellowing and becoming brittle in just a few years due to acidity. Acids can migrate to other materials, so inspect high quality papers that have been in contact with acidic sheets for signs of damage like yellowing or brown patches. Any paper can develop fungus in humid or damp conditions; any sheets with mildew spots should be discarded.
The same is true of unprimed canvas in terms of moisture and mold. Old stock that appears clean is fine to use. Rolls of acrylic-primed canvas and pre-stretched canvases store well for years. Oil-primed canvas can darken, especially when stored in dark conditions, but this is harmless and reversible by exposure to sunlight. Oil-primed canvas that shows signs of cracks or brittle priming should not be used.
It’s likely that most of your old supplies will still be in good condition, but taking inventory and weeding out expired or damaged materials is an important measure to make sure you have everything necessary to make your studio time productive.