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Introduction to Using Acrylic Colours

Acrylic paints are simple to use and clean to handle, which makes them suitable in a wide range of fine art, decorative and craft applications. Acrylic paint can colour practically anything. It is resilient and flexible and can be applied to all kinds of surfaces. While used by artists on stretched prepared canvas, paper or board, acrylics can also be applied to wood, leather, paper-mache, fabric, cement, glass, brick, pottery – almost any non-greasy surface.

Acrylics are extremely versatile. They can be used straight from the tube; brushed, poured or sprayed. They can be applied in thin layers of transparent glazes or applied in thick impasto brush strokes. Diluted with water, they can be used in washed or used as a dye-like stain on fabric or wood. They are suitable for airbrushing, marbling, fabric painting and stencilling. When blended with different mediums a wide range of surfaces and textures can be created. KROMA acrylic colours are fully compatible with other brands of high quality artist’s acrylic paints. However, as some student grade acrylic paint is made using resin that is not 100% acrylic, we advice testing before blending KROMA acrylic colours with paint that is not labeled artist’s or professional quality. 

Brushes and tools should be kept from drying and should be washed with soap and water. Stuck lids can be loosened by immersing jar in hot water, which softens the film of dried paint on the threads.

 A quick lowdown on some technical terms: 

Pigments: very small insoluble particles; the raw material that gives paint its colour.

Hue: colour, independent of how dark or light it is, or how dull or clean it is.

Saturation: the degree of a colour’s brilliance or dullness independent of its hue.

Tonal Value: how light or dark a colour is.

Medium: the clear body of the paint without pigment added. Used to extend paint to make a colour “go further”, as a final coat, or for image transfer or mixed media work.

Gesso: primer for preparing surfaces for painting in acrylic or oil.

Mass Tone: colour applied thickly, straight from the tube.

Under Tone: colour applied thinly or diluted by medium or water, usually increasing translucency and allowing for the under colour to shine through, increasing the vibrancy of colour.

 

Tint Strength

Pigments differ from each other in many ways, one of which is tint strength. These examples show a high and low tint strength pigment of a similar colour. Each mix was made with the same proportions of colour to white. High tint strength pigments, though usually more expensive are more powerful, stronger, colours and so “go further” when extended with mediums, diluted, or used in tints. Low tint strength pigments are often more natural looking colours and because they are usually more opaque, have better coverage. Low tint strengths are easier to work with when making precise colour adjustments in small increments.

 

 

Desaturate with Earthtones

When you don’t want bright colours, what do you do? There is more than one way to adjust colours to make them less saturated (duller). The trouble with using black is that it often shifts the colour as it dulls it down. By choosing an earth tone pigment that is a similar hue to the colour that you wish to dull, you can desaturate without shifting the colour. Yellow oxide is good to desaturate yellows, for example, while red oxide, is good to desaturate reds. Raw titanium is a white that has not been fully bleached. It can be used as a convenient way to lighten colours and desaturate them at the same time.

  

Consider Transparency 

Pigments have many different properties, one of which is their degree of transparency, or translucency; how much light will pass through the pigment particles. Here is an example of a more transparent pigment, sap green, next to a more opaque pigment chromium oxide green. The transparent pigment seems to glow, with an undertone of a fuller and lighter colour – you can see into the paint layer. The opaque pigment reflects light off the top surface and not from within – the white of the paper is hidden. Opaque pigments are often less bright, more natural looking colours, which are better able to hide the underlying surface.

 

Transparent and Opaque Colours

 

Use and Glazing Technique

By diluting paint with clear acrylic medium or water and applying thin translucent layers onto a white or light coloured background, you will achieve a lighter colour, while keeping the colour saturation high. The phthalo blue square below, which was lightened by glazing, appears to be more brilliant than the one lightened with titanium white to the same tonal value, which has a more “pastel” appearance. This effect is most pronounced when using high tint strength transparent pigments.

 

 

Add Some Sheen

When a painted surface is matte, light is scattered when it reflects off its surface. All colours can be made shinier by adding gloss medium to the paint of by adding a coat of feeling of depth. By making your painting shiny you will allow more colour from within the paint to reach your eyes and less light will scatter from the surface. See applying acrylic medium in the technical tips section.

 

 

Applying Acrylic Mediums

Before they are dry, acrylic mediums appear milky-white. When dry they become perfectly clear. They can be added to acrylic colours without limit.

 

 

Our three clear mediums have been formulated to have different viscosities. By diluting the gel medium with water you will create a liquid which may have the same consistency as fluid medium, but because it will contain less resin solids it will create a weaker and thinner film when dry.

Artist’s quality paint is formulated to have maximum pigment loading. We put as much ground pigment in the acrylic resin as is possible in relation to the properties of each individual pigment. While artist’s colours can be used straight out of the tube or jar, using a variety of clear mediums can vastly increase the range of effects that can be achieved. Because artist’s paint is a highly concentrated product, clear mediums can be used to extend the paint, to make it go further. This is especially true when working with more expensive, high tint strength colours, like dioxazine violet, for example. To extend the paint without considerably altering its viscosity, matte medium is a good choice. Adding gel medium will make the paint slightly thicker, while fluid medium will create a fluid paint.

Some colours are so strong in tint strength that they look very dark, almost black, in their unaltered form. By adding clear acrylic medium it allows the colour to be more visible by making a more transparent film. By adding clear medium to the paint and applying it in layers you can achieve a depth of colour and a type of colour mixing that is not possible in any other way. This technique is called glazing, and is particularly effective with high tint strength, transparent pigments like phthalos and quinacridones. Fluid medium is suitable for use in this technique because its flow properties allow thin, even layers to be made easily without holding brush strokes. Because acrylic is fast drying, it is a convenient material for this type of painting.

Artist’s colours are made up of two main ingredients, pigment and acrylic resin. The acrylic is the binder that holds the pigment together in a strong film. Clear mediums are essentially paints without colours. Acrylic resin is methylmethylacrylate, the same material that is in acrylic sheeting, known as plexiglass or perspex. Unlike most other plastic resins, acrylic has outstanding lightfastness and weatherfastness. Most other plastics break down in ultraviolet light exposure, and are subject to yellowing and brittleness. Acrylic’s resistance to ultraviolet light and outstanding optical clarity make it a top quality artist’s material. It is one of the clearest substances available.

For these reasons clear acrylic mediums are suitable as a “varnish” type coating for finished work. Because different pigments have different sheens, some areas of a painting may appear shinier than other areas. Artists sometimes prefer to unify the sheen of a finished painting by applying a layer of clear medium to its surface. Using fluid medium as a clear coat will make the colours appear more saturated because its sheen is glossy. Using matte medium as a clear coat will diminish glare. It is only the sheen of the last layer applied to a surface that will determine its final sheen.

Since they don’t yellow or get brittle, these mediums are also suitable as a final protective layer on top of papier-mâché and mixed media work. They are especially useful in collage and decoupage as they perform both as an archival quality adhesive and as a clear coat.

While gesso is more usual in preparing canvas for painting, clear mediums can also be used. In order to create a complete seal the first layer of medium can be diluted with water so that it can soak in and penetrate the fibers of the fabric. Subsequent layers should be used full strength.

Oil painters usually have several types of oil on hand as well as turpentine for diluting. Acrylic painters will get the most out of their colours, and broaden their repertoire of techniques when they have different types of clear acrylic medium available to modify their paints, as well as water as their dilutant. 

Projects and Techniques  

 

 Different Surfaces

Acrylics can be applied to almost any non-greasy surface. Kroma acrylics are ideal for colouring or decorating many surfaces as they are flexible and waterproof once dry. All the colours are lightfast and (with the exception of zinc white and cadmium red and yellows), are suitable for use in outdoor projects. For the best adhesion, a smooth, glossy surface should be lightly abraded before applying paint and should be free of all wax and oil.

 

Murals

Acrylic paints are ideal for use in mural work. In fact the very first acrylics were formulated for the work of Mexican muralists in the 1950’s.

House paints, though available in many colours, always contain opacifiers for coverage, so tend to be more subdued and give less vibrant colours than artist’s acrylics. The most important factor in successful adhesion is the suitability and preparation of the underlying surface. Previously painted walls should be thoroughly cleaned with a commercial strength cleaner, then lightly abraded with sandpaper to create a rough surface for the acrylic paint to grip on to. A problematic wall can still be used for a mural if panels of plywood or other suitable material can be affixed securely.

All the KROMA colours are suitable for indoor murals. For outdoor mural painting there are, however, some colour considerations to be noted. Though rated excellent in lightfastness, the cadmium colours are not considered weatherfast, being especially sensitive to the combination of light and moisture, and so outdoor use of these colours should be avoided. Suitable alternatives can be found in the hansa and napthol ranges. Zinc white has a tendency to “chalk” when used outdoors and so titanium white should be used instead.

In some locations it may be appropriate to apply a clear protective layer over a mural to prevent damage from scuffing and dirt in high use areas or to allow for the easy removal of possible graffiti. Solvent based clear “Varathane” products or commercially available “Anti-graffiti” coatings can be used for this purpose, but the mural must be fully cured before this process and there must be no possibility for moisture to become trapped under the sealed surface, or blistering and adhesion problems may occur. Using a water-based  sealant will allow the acrylic paint to breathe, and allow moisture to escape, but may be less durable. Note that some non-acrylic clear coats may yellow with age.

 

Fabric Painting

 

Paint marketed as “fabric paint” is usually a specially formulated acrylic paint. KROMA acrylics are also suitable for most fabric painting applications.  The colours can be used directly on fabric, lightly diluted with water to a brushable consistency. To apply an even colour to a larger area, the paint should be diluted further to allow it to penetrate the fabric. The amount that the paint should be diluted will depend on the weight of the fabric and the style of the painting. Heat setting is not required, but for the paint to be fully cured allow four days to dry in a warm non-humid place. Once fully dry the paint is permanent and machine washable.

In theatre and film industry acrylics are used in “break-down” to make costumes and props appear appropriately distressed or worn. 

 

Painting on Wood

 

 

KROMA paint can be applied directly onto woonden surfaces. Opaque colours, such as the earth tones and cadmiums are easiest to work with on wood. To show up well on wood, the brighter, more transparent colours, like pthalos and quinacridones should be blended with white, or applied in diluted layers over a light background.

Unprimed wood, such as the red cedar used in traditional west coast native work, may tend to draw the paint into or along the grain preventing sharp edges from being drawn easily with the brush. To Prevent this "bleeding" the wood can be prepared or "sized" with several layers of diluted clear acrylic medium.

An additional layer of clear acrylic medium can be added to the finished work to create a uniform sheen.

 

 

 

Airbrushing and Marbling

Airbrushing can be used in super-realist paintings, soft shadows and highlights, or simply to create a uniform surface without brush marks. For use in an airbrush we recommend thinning KROMA paint with water and clear fluid acrylic medium. The exact proportions required will vary from colour to colour, as each pigment has different characteristics. The full extent of a transparent pigment's brightness and hue can be most clearly seen when airbrushed in layers over a white surface.

Similarly KROMA acrylics can be used diluted with fluid acrylic medium in marbling techniques.

 

Gel Transfer 

A layer of clear acrylic gel can be used to transfer a photocopied image onto a different surface such as a stone tile, canvas, or a T-shirt. Once the gel is dry the paper that the image was on is soaked off in water.

 

Collage and Papermache

Clear acrylic mediums and gels can be used as archival quality adhesives in collage, decoupage and mixed media work. They will remain flexible and will not crack or yellow with age. they will noticeably outperform and 'glue' (which is often polyvinyl acetate) for this type of work. They can also be used to coat finished work, to strengthen and protect, or to create a unified sheen. The acrylic medium and artists colours are also great for paper mache projects for the same reasons and with the additional benefit of adding strength and flexibility to the object.