Paints consist of a color pigment + a binder + a vehicle (such as oil or water). The binder can be synthetic (alkyd resin or acrylic) or natural (plant oil or resin, natural latex, animal glue, casein, milk, egg, or cellulose). Most paints emit VOC's (volatile organic compounds) which contaminate the indoor air long after the paint cures.

Natural paints usually dry faster and contain fewer VOC's. Generally, a low VOC paint contains less than 50 grams per liter, while a no VOC paint has fewer than 5 grams per liter. Lower VOC amounts are found in natural paints and in flatter sheens (more binder = more gloss = more VOC's). Lower VOC content equals a naturally, healthier paint. Here are some important reasoning points:
1. Synthetic paints trap moisture and may bubble or crack over time.
2. Natural paints remain flexible, moving with the natural expansion and contraction of wood and metal.
3. Synthetic paints are statically charged and so attract dust.
4. Natural paints 'breathe' negative ions which purify the indoor air and resist dust.
5. Synthetic paints contribute to 'sick building syndrome' causing headaches, eye irritation, and lethargy.
6. Most synthetic paints contain VOC's. Short-term exposure may cause headaches, nausea, dizziness, fatigue, and blurred vision. Long-term exposure (i.e. all you painters out there) may cause asthma, emphysema, dermatitis, memory loss, and bladder and lung cancer.
7. The average indoor environment is 10 times more polluted than the external environment. So why not use paints that keep your indoor environment healthy?!

Tips: Each coat of plaster, primer and paint must cure fully before the subsequent coat is applied-otherwise your finish may remain odorous and tacky. Also, good ventilation is key-it speeds drying time and is healthier for the painter and the occupants. Use fans and open windows to allow for 'offgassing' (from VOC's). Make sure that each coat (plaster, primer, paint) is completely dry before applying the next coat. Visit www.greenseal.org for specific product information.

Recipe for a homemade casein color-wash
* Combine juice of 1 lemon with 1 liter of skim milk and set aside overnight in a warm place to curdle.
* Strain mixture with cheesecloth and set aside curds.
* Mix with color paste (make a color paste by mixing 4 tbsp dry mineral pigment with a bit of water)
* Stir often and apply within a day onto walls prepared with a flat base coat.
* Apply with 4-6 inch course brush in cross-hatch fashion.
Suitable for rooms with low moisture-not recommended for bathrooms and basements). Soap and water cleanup for brushes.