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[[File:PB164054_JPG.jpg|frame|Milk Paint]]

====Introduction====
The term [[Natural paint]] refers to paints made from natural ingredients such as water, plant oils, resins and dyes, natural minerals, milk casein, bees’ wax, and earth and mineral dyes.  Natural Paint is a healthy and sustainable alternative to conventional synthetic paint, which are generally high in Volatile Organic Compound (VOCs) emissions and are usually petroleum or lead based, making them energy-intensive to produce <ref name="Steen"> Steen, B., (2006). “Make Safe, Natural Paint.” Mother Earth News (218), http://www.motherearthnews.com/Do-It-Yourself/2006-10-01/Make-Safe-Natural-Paint.aspx [accessed 9/26/2010]</ref> and toxic waste at the end of their life cycle. Natural paints are durable, cost-effective and less harmful to human and environmental health.  

====What is paint?====
Four main components used to create paints are:  binder, pigment, solvent, and filler. Natural paints often utilize the already existing properties of the ingredients for these main components, whereas conventional paints tend to use synthetic and toxic paints for these components.

====Binder====
The binder component acts as the glue for paint to stick together and maintain grip between the pigment and applied surface. Commercial paint binders are derived from byproducts of refined crude oil, such as acrylic or vinyl. Instead, natural binders are made of materials such as casein (milk protein), linseed oil (compressed flax seeds), starch (flour), chalk, lime, oil, and animal or vegetable oil. Lime is used for antibacterial qualities and may be applied to interior or exterior walls. Milk based paints utilize the naturally existing casein as its binder which has the option for fine arts and interior walls. The majority of animal and vegetable glues are used in fine arts because of the chalky quality. For woodwork and fine arts, oil is the binder component. The choice of a binder depends on how much paint you need and the surface to be coated. 

====Solvent====
Solvents, also called thinners, give the paint a fluid component or workable consistency until applied to a surface. Commercial solvents contain VOCs which volatilize upon application and emit hazardous chemicals and decrease indoor air quality. Natural solvents such as citrus thinners and natural turpentine are preferable, but they can still emit low levels of VOCs <ref name="Steen"/>. Solvents add transparency, decrease drying time, and are used for cleaning and wiping away mistakes. Water is used as a solvent for lime wash, casein, and beer and vinegar glazes <ref name="Innes"> Innes, Jocaste. Around the House Paint Recipes. Boston: Bulfinch P, 1997</ref>. Natural paints generally produce low or no VOCs.

====Pigment====
Pigments give color to paint. Commercial paints use heavy metals and toxic compounds as pigments.  Safe environmental alternative would be pigments that derive from plants, insects, iron oxides, minerals, clays, herbs, nuts, berries, barks, carbon, charcoal, and soot. They are ground down into powder and usually boiled several times in water to remove impurities.<ref> Bacon, Richard M. The Forgotten Arts: Book Two. Dublin, NH: Yankee Inc., 1975</ref>

====Filler====
Fillers create texture and add bulk to paint. Common fillers include whiting (powdered chalk), talcum, limestone, mica, silica and marble. Clay is a popular filler to pair with flour, because it reinforces the binding ability of starch. Also, clay is abundant and potentially free if you have clay soil.

====Extras / Additives====
Other ingredients are often added to conventional paints to give them qualities such as fungicides and faster drying times.  These added ingredients can increase the toxicity of the paint.  Below is a table showing the biological effects of some main ingredients in conventional paints.

====Wheat/Flour====
The simplest and possibly the most versatile homemade paint is flour based. Many types of flour can be used for the binder, such as wheat or bleached flour. Clay filler is typically used with flour paint; however, chalk, mica, marble, limestone, or silica work as well. Flour paint typically consists of water, flour, colored and uncolored clay filler <ref name="Steen"/>. If a textured surface is desired then more coarse materials can be used, but should be checked to see if it is still applicable with a brush. This type of paint is very thick and tends to be hard on brushes. Flour paint can be applied to interior and exterior surfaces such as wood, drywall, wallpaper, stone, masonry, earthen and gypsum plaster, and other painted surfaces. 

====Egg/Oil====
Oil paint is suitable for exterior surfaces, and you can clean oil-painted surfaces regularly without damaging the paint <ref name="Steen"/>. Usually an oil paint is made up of animal or vegetable oil, pigment, white spirit solvent, driers, and/or resins. This paint is most commonly made with linseed oil, natural solvent, and pigment. Raw linseed oil heated to a high temperature (but not boiled!) ensures more durability. Oil paints can take a long time to dry, some will never completely harden, but this property gives the paint the advantage of remaining elastic as surfaces naturally swell and shrink <ref name="Steen"/>. Advantages of using oil paint include flexibility, durability, and rich textures. Disadvantages are ingredients can be flammable or toxic, and the room must be well ventilated <ref name="Innes"/>. Oil paints are often mixed with egg to decrease drying time.
====Milk====
Casein is the protein component of milk or also known as milk curds (quark) which can be made or bought in powdered form, but is very easy to make at home. This type of paint can be applied on multiple surfaces, is naturally resistant to fungal growth, and lasts a long time. Casein paint must be mixed to specific proportions to prevent cracking, peeling and dusting off. It is important to allow each coat to dry completely, because the paint will become increasingly opaque as it dries <ref name="Steen"/>. Casein based paint can be applied to interior and exterior surfaces. Casein paint consists of nonfat milk, lime, water, filler and a pigment <ref name="Steen"/>. Lime is commonly used with casein because of its adhesiveness and its natural water resistivity.

====Blood====
These paints are mixed with dark pigmented pastes. They are weatherproof and are used indoors and outdoors on rough or planed wood. The drying time is approximately two hours and the lifespan can be up to 200 years.

====Disposal of Paints====
Most conventional paints are considered household hazardous waste and must be disposed of accordingly. One million tons of waste is produced annually from the manufacture of polyurethane varnish <ref> Going Solar (2009). Conventional Paint Information. http://www.goingsolar.com.au/pdf/catalogue/gs_bio_about_paint.pdf [accessed 11/22/2010]</ref>. Natural Paint can be composted or thrown away and some are even edible!

==References==
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[[Category:Natural paint]]
[[Category:Engr215 Introduction to Design]]
[[Category:HBCSL]]