Paint is essentially any pigmented liquid used to form an opaque coating over a surface. Paints generally consist of 2 to 3 different components - Pigment or dye (which provides the actual color of the paint), binder or vehicle (this forms the actual 'coating' of paint, like a piece of film), and/or solvent (not always mixed into the paint itself, this helps to 'break' the paint, allowing it to flow).
Pigments are usually granules of color and can consist of either natural or man-made chemicals or substances. Pigments don't really 'produce' color, instead they reflect light at certain wavelengths, forcing your eye to 'see' that color. For example, a blue pigment is 'blue', only because it doesn't reflect red or green wavelengths (light).
Pigments themselves have become huge in recent years for weathering techniques, thanks to companies like MIG Productions and Tamiya, due to their nature of eliminating the binding agent and using water as a solvent. This produces stark color contrasts which are able to flow into cracks and crevices better.
The binder or vehicle is what forms the 'film' component of paint. The binder is probably the least known, but most important, element of the paint. Depending on the type of binder and how much is used affects how paint flows, its coverage, and its drying time. Binders are generally of 3 types - resins (like those used in acrylics), plastics, or oils/fat (like those used in oil paint).
The type of binder used affects the type of solvent that must be used to dilute the paint or clean it from a surface, like a brush. Paints which use resins are generally described as 'water-soluble', which means they can be cleaned or diluted with water. Enamel paints sometimes use plastic or oil as a binder, and must be cleaned or diluted with some type of chemical thinner. Oil paint uses oil as its binder (hence the name) and must be cleaned or diluted with mineral spirits or turpenoid.
Drying Vs. Curing Times
Here's a good chance to make a small, but important, side-note. Two terms I see used quite often and (unfortunately) interchangeably are "Drying Time" and "Curing Time". These are NOT the same thing!
"Drying time" is the time is takes for the solvent to evaporate. "Curing time" is the time it takes for the binder to polymerize (essentially, this means when the binder is set or dry). A paint can be dry to the touch, but not be fully cured. This distinction is important if you plan on masking a model for further painting, applying sealant, or over-painting with a harsher solvent. If the paint is not cured, you risk having the paint come off, crackle, or dissolve completely.
If a paint doesn't list a cure time and you don't want to risk that nice paint job, put the miniature aside either overnight or 24 hours and work on something else in the meantime.
When any paint is finished drying, it has a certain level of specular reflection, AKA "glossiness". Flat finishes reflect little or no light and are good at hiding minor imperfections in surface detail. Flat finishes are highly sought after for military modeling, especially for military vehicles and camouflage.
Matte finishes reflect a bit more light than a 'true' Flat finish (a good example of this finish are prepared canvas at any art store). Matte finishes are the most prevalent finish for miniatures in general , mostly because acrylics are so common and most sealants have a matte finish.
Satin (sometimes called Eggshell in house paints) reflects a good amount of light, especially when hit from higher angles. Semi-gloss is fairly self-explanatory; it will reflect light well but lacks the real mirror-shine and depth of a 'true' Gloss.
Gloss reflects 90-100% of the light and has a deep, mirror-like quality. Gloss paint shows imperfections in the undercoat much more than any other finish and to get good results, must be sanded with fine grit sandpaper between coats to get the "perfect finish". For that reason, it is generally avoided outside model car painters.
Acrylics: Probably the most widely used paint for modelers today. Acrylics consist of a pigment and resin (or sometimes, plastic) binder and are almost always water-soluble. Citadel, P3, Reaper, Vallejo, Tamiya Acrylic, and Testors Acryl are all acrylic paints. Water-soluble acrylics can have anywhere from a matte to semi-gloss finish, depending on brand.
You can usually airbrush with acrylics by thinning them with airbrush thinner or illustration base.
Gouache: Not generally seen amongst modelers, Gouache consists of pigment suspended in water (a solvent), with just a bit of natural resin-like binder (Gum arabic). It is water-soluble, lacks high opacity, and reacts much like watercolors. Gouache generally has a matte or satin finish.
Watercolor (Washes): Watercolors are pigments or dyes suspended water (a solvent) and are usually heavily thinned with water before application. Washes are similar to watercolors but are generally dyes already diluted in water, ready for application. Watercolors and washes have the least opacity of all paints. Watercolors generally have a satin finish, while washes (being dyes) can have either satin, semi-gloss, or gloss finishes (usually depending on brand and user dilution). Citadel, Reaper, Vallejo, & P3 all produce washes.
You can generally airbrush with watercolors thinned with a little water.
Inks: A dye with a complex component of binders and solvents, usually water-soluble (but not always!). Pigmentation is inks is very high, making them difficult to control and hard to dilute. Inks almost always have a gloss finish.
Oil: Oil paint consists of pigment bound with oil (usually linseed) or fat, soluble only through mineral spirits or turpenoid. Oil paints take a LONG time to dry/cure but are good for blending. Generally, the opacity of oils is greater than that of acrylics. Oils are sold in tubes and even a very small tube will last most modelers years, making it very cost-effective. Oils can have a matte or satin finish.
Enamel: Enamel paints consist of a pigment, heavy concentrations of binder (usually resin), and a little solvent. Because of its high binder content, enamels 'wear' well but generally take longer to cure than acrylics (but not as long as oils). Enamels almost always must be diluted/cleaned with a chemical solvent, popularly known as "thinner". Enamels can have any type of finish and its usually indicated on the bottle. Humbrol and Testors (non-acryl) are the most widely available enamel modeling paints.
I've heard you can airbrush with enamels if properly thinned with thinner or rubbing alcohol.
What Paint Is Best For Me?
The type of paint you want to paint with is a matter of personal preference but there are some general guidelines for picking paints. Usually, most modelers tend to use a combination of 2 or more types of paints for specific applications. For example, I mostly use acrylics and washes for general painting, oils for weathering, and occasionally enamels for base-coating or for military vehicles.
If you want a paint that will let you blend right on the model itself and will stay "open" longer, oils are a good choice. Oils are also good for weathering (just be sure to adequately cure and seal any other paints before applying weathering techniques with oil!).
If you plan to be very hard on your paintjobs (transferring from play to storage, etc.) or you plan on doing military models, enamels are a good choice. Enamels wear well and are generally the "toughest" type of paint, however enamels can dry quickly and are difficult to blend well.
Watercolors and washes are really only good for applying shades and washes to other paintjobs, due to their lack of opacity.
Acrylics are a good midpoint of all the above qualities - they wear well, can be blended and their "open" time extended (with Slow-Dry medium), can be diluted to have the qualities of a wash, etc. Acrylics are also the most cost-effective of all paints.
The Size Issue - Why Smaller Is Better!
In this age of Costco and Sam's Club, I know there are a lot of you out there, going through the art supply store and thinking "why spend $3.00+ on a 17ml bottle of paint, when I can spend $7 and get almost 5oz.?" Well, there are a few good reasons why not.
First, at the scale most modelers paint, you will almost never use up even a 5oz. bottle of paint before the paint dries out or goes bad. Second, larger bottles of paint take longer to mix correctly than a smaller size does. Additionally, larger bottles of paint take up more storage space and require larger paint racks than small bottles do.
However, if you plan to paint LARGE models or use a lot of paint these may be more economical. if neither of these apply to you, but you're still tempted to buy larger bottles/tubs, stick with Black, White, and the primary colors.
Craft, "Student" ,"Artist", & "Value" Grade Paints
Directly related to the above, some of you may be tempted by the low, low cost of "student's" or "artist's" grade paints. Stay away!
The reason why these grades of paint are so cheap is because pigment is expensive. Less pigment = cheaper paint. And while cheap paint may be okay if it's good quality, cheap paint with bad pigment ratios usually means the paint won't cover well, will take longer to cure, and may not mix well with other paints.
Craft paints are sold in larger hobby stores and craft stores. While some modelers use craft paints with good results, the problem with craft paints is two-fold. First, craft paints are generally sold in bottles no smaller than 4oz (going back to the size issue above). Second, craft paint pigmentation is generally of larger particulates than other paints and may dry with a lumpy/rough finish if no properly diluted.
The Proper Care & Storage Of Paints
Paint consistency is very important and all too often I'll see someone painting with paint from a jar or bottle that's gummed up, has paint on the rim/threads, etc. At the scale you'll be painting at, good paint is extremely important, moreso for modeling than any fine art.
Acrylic and enamel paint should generally have the consistency of slighted thinned glue or 2% milk (so I've heard - I'm lactose-intolerant so can't have the stuff....), free of globs or 'strings'. Washes should be free of dried "bits" and have consistent color throughout.
A good way to make mixing acrylic and enamel paints in the far is to add lead fishing sinkers (available at most sporting goods stores) or ceramic beads to the bottle.
Every time you open a jar of acrylic paint, you expose the paint to air, causing it to dry. This is why paint in jars should be transferred to a palette, so you don't cause premature drying of the paint. Enamels generally don't have this issue.
Oil paints should have the consistency of thick cream or paste. Don't worry if you see oil in the paint, that's good! Oil paint should be squeezed out unto a palette where the oil and pigment can be mixed - NEVER used from the tube!
All paint should be stored in a relatively cool place, away from direct sunlight, to avoid premature drying and sun-bleaching. Make sure that you keep your jars/bottles/tubes fully closed and to keep the threads free of paint residue, grime, and dust.
I Want To Paint..But I'm Broke!
Can you paint minis when you're poor or on a strict budget? Yes, yes, and....YES!
If you don't have much expendable income, it's still easy to not spend a lot of money on paints and supplies. Here's my suggestions:
- Buy at least 1 or 2 GOOD quality brushes (preferably kolinsky sable or good synthetics) in 00 and/or 1 sizes. Make sure they come to a perfect needle-like tip. Read my Brush Care 101 tutorial.
- Buy the basic and primary colors only. This includes: Black, white, red, blue, yellow, green. All colors can be made by combining certain amounts of each color. Print out a color wheel from the internet and blend, blend, blend!
- Buy a good solvent. Water is free but buy some Flow Improver - it's cheap!
- Buy a small palette. This should cost no more than $3-4.
- Buy a good can of primer, black or white (depending on personal preference).
Find a good place to paint that's out of the way and has good lighting (preferably an 80W+ bulb). Even buying all the above supplies, it should only cost $35-40 and you shouldn't need to get new supplies for awhile.
What To Do With Bad Paint
Globs of paint inside a bottle or jar mean either drying paint or, worse, curing binder! Small globs can generally be strained out by pouring the paint through old pantyhose. Discard the globs, clean the threads, add a little applicable solvent (not too much!), seal tightly, and shake.
If the globs are large or numerous (over 50% of the bottle), discard or return it (if new) and get another. Additionally, if any of your paint has completely solidified (i.e. it's too hard to break or squash), it's a good indication that your binder has begun to cure within the bottle. Paint that has been cured in the bottle is unsalvageable.
If you have just bought a bottle of paint and it is dry, has globs, doesn't mix well, etc. do yourself a favor and return the bottle! Any good art supply store, FLGS, or webshop should except returns of paint which are not in good shape. If a store doesn't accept a return of paint within 7 days of purchase, then don't patronize them again.
Remember, you are spending a lot of money on a little quantity of paint and there's no reason you should have to accept bad quality paint!