The following material is reprinted from the book "'Airbru.-li in Ceramics" (Copyright 1955 by Graphicraft Publications) by gracious consent of the author, J.Zellers Allen.Mr.Allen directs The Allen Airbrush Institute in Detroit and has won nation-wide recognition for his work in ceramic techniques.

An airbrush, quite simply, is a small .paint or color spray gun.There are two general types of airbrushes: single-ac­tion and double-action.

A double-action airbrush derives its name from the fact that the control lever has two actions: down for the release of air, and back for release of color.As will be easily understood, this double ac­tion enables the operator to increase or decrease the flow of color during a stroke, which is a distinct advantage, and which is the feature that enables an artist to really create with airbrush.In using a double action airbrush the lever is pushed all the way down in releasing air, because it is not the type of valve that permits any regulation other than open or closed.The control is not always pulled all the way back in releasing the color, because the amount of color released depends on the extent to which this lever is pulled back.For a little color, pull back a little; for more color, pull back more.

A single-action airbrush gets its name from the fact that the small finger lever, used to control the flow of air and color, has only one action, up and down—or, more accurately, down and up.You push the lever down and, when you release it, a spring pushes it back up.When depressed, this control releases both air and color.The control for the amount of the color released is located elsewhere on the brush and must be adjusted to the operator's liking or re­quirements previous to activating the con­trol lever.This is a disadvantage despite the fact that some advertising carries the statement: "Air and color controls are in­dependent of each other," as though it were advantageous.

From the foregoing brief descriptions, it is obvious that the double-action airbrush is the more versatile of the two.This fac­tor should be kept in mind when choosing an airbrush for ceramic use as well as for any other purpose.

If you buy a single-action brush, there will come a time when its lack of versatility and flexibility will hold you back, and you will be sorry that you did not get a double-action brush.If you choose a double-action brush it will last you a lifetime, with proper care, and its only limitation will be your imagination and your continually growing ability to handle it.You will find that the difference in price is not great, and that the difference in what you will be able to accomplish with it is entirely out of proportion to the slight additional cost.

Frankly, there is not much to learn about the operation of a single-action brush that is not covered by the instruction leaflet that came with it.What more there is to learn about it will be covered by the in­structions presented in this book, except that the owner of a single-action brush will have to substitute the separate adjustment of his brush for the pull-back of the double-action brush.

Two general types of air supply are available for airbrush use: compressed air and carbonic gas.Of these, the air com­pressor is the more popular and practical.

It is a very sound idea to buy the best air compressor you can afford.Your air­brush work will be no better than your air supply will allow it to be.You probably won't need the largest compressor you can find, but you will never regret buying a good one—one that will adequately handle the brush, or brushes, you may wish to use.

The other practical air supply, liquid carbonic gas, is more expensive than a compressor, in the long run, but has the advantage of being silent and clean.Car­bon dioxide in twenty-pound cylinders may be obtained in any locality having soda fountains—and what localities do not have them? A pressure gauge and regulator, to permit the use of gas for airbrush purposes, may be purchased from your local ceramic or art supply store.Full directions for at­taching it to a standard cylinder of CO2 will accompany the regulator if it is one that was supplied by one of the airbrush companies.Read them carefully and fol­low them to the letter.

Regardless of the kind of air supply used, cleanliness and care in its use are as de­sirable as in the use of your airbrush.

One point, which seems to be very per­tinent in the application of airbrush to any kind of work, needs to be made right here: Airbrush finds its greatest use in conjunc­tion with other methods of color applica­tion! So, you see, you are not to throw away your red sable brushes and your sgraffito tools, because you will be using them right along with the airbrush—if you use the airbrush properly.

Airbrush does, very easily, many of the things that are extremely difficult to do with other methods.On the other hand, certain things can be done much better with your regular methods than with air­brush! A blend, which one can achieve almost without effort with the airbrush, is not easy with regular brushes; whereas, a sharp definite line of solid color is usually difficult with the airbrush, but easy with regular brushes.Airbrush will supple­ment your other tools, not replace them.

Obviously, if you were learning to be a dressmaker, you would not do your prac­ticing on expensive silk or satin.Neither does it appear sensible to practice airbrush on greenware or bisque.Confine your first airbrush work to the cheapest of paper, se­cure in the knowledge that when you have mastered it sufficiently to apply it to a pot, the clay surface, raw or bisqued, will accept the color just as well, and sometimes better, than the paper surface.

There is an old Alienism in airbrush in­struction to the effect that the one abso­lutely essential thing in the making of a good airbrush user is a large wastebasket! Don't spare the paper.

How to Hold and Operate Airbrush

If you hold a pencil in the most common way, that is, resting on your middle finger between the first joint and the end of the finger, held there by a downward pressure of the tip of the forefinger, a downward and to the right pressure of the thumb, you need only substitute the airbrush for the pencil to have the proper hold on it; the only difference is that instead of "pressing downward on the body of the airbrush, as with a pencil, you place the tip of the fore­finger against the small control lever pro­jecting from the top of the airbrush barrel.

Examine the accompanying photographs carefully.You will find that this grip will allow very easy manipulation of the control lever.A downward pressure of the lever, the first necessary action of this control in every instance, is very naturally accom­plished.The "pull back" to release color, while not so natural to a pencil user, is, nevertheless, not out of keeping with the position and the grip.

Refer frequently to the photograph showing the proper way to hold the air­brush.Notice the position of the individual fingers, especially the forefinger.Greater control is possible if the forefinger is kept slightly bowed, or tense, at all times, even when the control lever is completely for­ward and not releasing color.

It is literally true that you work in three dimensions with the airbrush.You must work to and from the surface to which you are applying color as well as back and forth across it.This leads to slightly fur­ther complication when working on curved surfaces of pottery, which, of course, is an­other reason for mastering the technicali­ties of airbrush on paper.

Synchronization

There are five factors to synchronize when operating an airbrush.They are:

1. The "push down" for air.
   
   
2. The "pull back" for color.
   
   
3. The distance of the airbrush from the receiving surface.
   
   
4. The direction of the stroke being made.
   
   
5. The speed with which the airbrush is moved.

Let us consider these five factors in order:

1. The Push Down for Air.As mentioned before, you always push all the way down to release the full pressure of air.This valve on the airbrush is not the kind of valve which permits partial air release.If pressure needs changing, it must be done at the source, through the medium of an air regulator which reduces the pressure that is released from the air tank.
   
   
2. The Pull Back for Color.This action differs from the push down in that it is not always a completed action—it is not always pulled all the way back.The extent to which this lever is pulled back controls the amount of color released, and since you do not always want to release a full blast of color, you do not always pull all the way back on this lever.

Restraint is the rule of thumb for activating this lever.Remem­ber this: You build color with the airbrush.Seldom is the full intensity of the color achieved with once-over spraying.Re­peated light sprayings, permitting that "build up," are more easily controlled and less likely to result in costly errors.It is easy to add color with the airbrush; diffi­cult, if not impossible, to remove it once it has been applied too heavily.Make haste slowly.Speed, if desired, will come with practice.

3. The Distance of Airbrush from Surface.The distance of the airbrush from the surface to which you are applying color will regulate the size line or width of spray that you will get.It also helps to determine how far back you can pull on the color re­lease lever.The farther away from the surface, the more you can pull back on the control lever without getting "wet" spots.

Working "wet" is to be avoided, gen­erally, because the same air that applies the color will then cause it to blow outward from the wet area in little rivulets or fingers of moisture.Sometimes this effect can be turned to account.

This advice about working "wet" does not apply when the airbrush is used for all-over application of color or glaze, because, when coating something in this manner, the airbrush, or ware, is kept constantly in mo­tion; consequently, it does not remain in one spot long enough to blow the color.A wet coating for such purposes will give a better finish to the completed ceramic piece.

4.Direction of the Stroke.All airbrush work is done with "strokes." A stroke might be described as the line or area cov­ered from the time the control lever is pulled back to release color until it is pushed forward to stop the flow of color.To master the making of lines without knobs or splashes is to master the basic air­brush strokes.Everything you will ever do with the airbrush will be done with this basic stroke.From this it is easy to under­stand why it is imperative that you master the controlled line.The "direction" of the stroke will determine the results of your airbrushing, exactly the way that the di­rection in which a pencil point is moved in contact with paper determines the object that is drawn on the paper.

5.Speed with which Airbrush Is Moved.The speed with which you move the air­brush over the surface while releasing color will determine the amount of color applied to the surface by the stroke.

Let us say that you make two lines ex­actly fifteen inches long, with the airbrush exactly the same distance from the paper in both cases, pulling back exactly the same degree to release color for both of the lines.Now, if it takes one second to make the first line, and two seconds to make the second line, you will have applied exactly twice as much color to the second line as you did to the first.The second line will be heavier and darker.The nature of the air­brush is such that, if you pull back on the control lever to release color and keep the brush aimed at one spot, it will proceed to spray every drop of color in the cup on that spot; consequently, the longer it takes to make any given stroke, the more color will be applied during the stroke.•

Are You Ready To Move Onto The Next Lesson? Click Here...