Painting

Airbrushing

Airbrush questions... and answers!

Which airbrush should I use?
The single action external mix airbrush is the simplest type to operate and is best for jobs that don't require much precision. Double action airbrushes are more complex to operate but possess wonderful qualities of air volume control and sprayed liquid volume - perfect for fine, detailed art work.

What liquids can be sprayed?
Any liquid that can be thinned to the consistency of milk can be sprayed through an airbrush. However, if some liquids are thinned too much, they won¹t perform properly. Generally, thick liquids such as textile paints and ceramic glazes should be thinned cautiously and a simple single action airbrush with its largest needle/cap/tip option should be used. The thicker the liquid, the higher the compressor pressure required. Thinner materials such as dyes, inks, watercolours and some other thinned paints can be used in a double action airbrush and/or lower pressure may be used.

What is a single action airbrush?
A single action airbrush is the simplest type. When the finger button (air control) is pushed down, colour will be sprayed at a pre-set rate. This rate is easy to change - simply stop spraying for a moment and turn the colour valve slightly. They are useful mostly for area coverage in such activities as hobbies and crafts, stencilling, and mural work. Acrylics, ceramic glazes, lacquers and enamels are suited to a single action airbrush. Most single action airbrushes are external-mix types. They mix the air and the colour outside the tip and are therefore less likely to clog if heavier materials are sprayed. If using an internal mix airbrush, the liquid must be thinned because the air and liquid are mixed inside the body of the airbrush. Internal mixing produces a finer spray.

How is a double action airbrush different?
Only one difference - but a big one! Slowly pulling back on the finger button will gradually increase the amount of colour sprayed. Thus, you are able to control such things as the width of the line or area of tone, the intensity of the colour or the gradation of value, all while you continue to spray. Obviously, that type of versatility isn't necessary for every task but for artwork, it's great!

How are the liquid and air mixed?
The liquid is fed into the air stream either by siphon (sucking) action or gravity. The siphon-feed types work just like sucking a milkshake up through a straw, and it takes one or two seconds to get it working. The gravity-feed types are quicker because the colour cup is located on top and the fluid flows directly down into the airstream. This is helpful when making a lot of colour changes.

How much air?
Most airbrushes will work just fine on clean, dry air at 1/2 to 1 C.F.M. (cubic feet per minute) flow and 20 to 45 p.s.i., depending on fluids being sprayed

Will I Need A Moisture Trap?
Yes.

A moisture trap that is inserted into a (cut) airhose will effectively reduce the amount of moisture in your air line. This is particularly important in warm and/or humid conditions. Moisture can also accumulate in your airbrush hose overnight so spraying through the airbrush for a few minutes before you begin to work will clear the condensation from the line.

Cleaning is vital...
An airbrush is a precision instrument and should be cleaned with the proper solvent immediately after each and every use. ... or it won't work.

Attention!
When using Air Erasers, safety glasses and masks are required.

Thin those liquids
Thick liquids to be sprayed through an airbrush should be thinned with the proper solvent for the liquid, to approximately the consistency of milk.


Painting - Varnishes

These are protective coatings - usually with resin content, which are deposited over a paint film. They provide protection from dust and dirt, to water soluble mediums and fugitive pigments. Varnishes also provide a uniform surface to art works. They vary the transparency (or plasticity) of the paint. They also affect the drying speed of the painting and the flexibility of the finished surface.

Varnishes are divided into:


Painting - Thinners

Thinners are special liquids designed to thin paints and mediums but because they are highly volatile, i.e. evaporative, they do not stay in the paint film.


Painting - Oils

Those used in paintings are known as "Drying Oils" eg, linseed, standard oil. When spread thinly the oxygen and light in the atmosphere act upon it and the film becomes sticky and thick, finally drying to a hard but flexible film. It takes months (6-12) for an oil painting to dry sufficiently to receive its final varnish.


Painting - Mediums

Mediums are a group of compounds used in conjunction with artist colours as an additive or supplement. They are blends of two or more materials added to paint to provide whatever painting properties or consistency the artist desires (eg, altering the thickness, flow, and drying qualities of the paint.) It also protects artwork from atmospheric conditions and ageing. These changes are best made with mediums which give the paint a higher degree of permanency and flexibility but do not cause wrinkling in the coat of paint or yellowing with age.


Paint Storage Tips

To guard against bacteria and mold, manufacturers of paint products add preservatives to these products. Diluting the product will decrease the effectiveness of preservatives. Below are some tips on storing paint products to maximize their shelf life:

All paints are subject to eventual spoilage once opened and exposed to air and other contaminants. Most spoilage is a result of cross-contamination from common sources such as air, water, people, brushes and other utensils. Proper storage and usage will reduce potential sources of contamination and extend the life of your paint.

 


Silk painting

Steam fixation
Colours gain their full brilliance after steam fixation. Steaming can be done in a pressure cooker or a bamboo steamer (place steamer on top of Chinese wok). Roll silk in absorbent paper, e.g. butcher's paper, and place in steamer. Steam for a minimum of 40 minutes. After steaming the colours are completely fixed and are fast to washing and dry cleaning. Avoid creasing the silk as the steaming will make creases permanent. Creasing is minimised by rolling silk in fine cotton (wash cotton after every use) instead of paper.

Dilution
Colours are diluted with water only but for completely uniform pastel shades or pale background colours mix with Silk Designer Diffuser. The diffuser retards drying of the colours and allows painting of large areas without leaving rings or halos.

Cold fixation
It is very important that the finished painting be left for 48 hours before fixation. Add 3 capfuls of fixative for each litre of cold water. Immerse silk, agitate 10 times and leave immersed for 1 minute. Hang to dry. Avoid crumpling silk. Use a tray as wide as possible. Colours change slightly during fixation. Can also be steam fixed - follow same instructions as used with Silk Designer Colours.

Why didn't it work?

Dyeing Precautions