Painting and Glazing Repaired Ceramic or Sculpture

The color and sheen match has to be perfect if it is expected to be seamless and invisible. To achieve good results, one must take into account the fact that the color could change as it dries and could change again once cold glaze is applied. The changes are sometimes making the color darker, sometimes lighter and sometimes the hue is modified. The paintings we use are mostly acrylics but at times we also use oil paints, mineral pigments or dyes depending on the projects. A good starting point for first time DIY  job is to use water base Acrylics.

Complete Repair Example Including Painting

How to Mix Color: Basic Theory

Any color can be made using the following nine colors: Blue, Red, Yellow (the primary colors), Green, Orange, Purple (the secondary colors), White, Black, and Ocher.

Understanding the basics is key when starting to paint. If you plan to paint repaired ceramic or sculpture and have painting experience, you can skip this paragraph. Reading the information below is helpful, but in practice actually mixing colors is essential.

Having a basic knowledge of the color wheel is really important.

Three primary colors, Blue, Red and Yellow: These are the colors that are impossible to mix from a combination of other colors.

The 3 secondary colors, Orange, Violet, and Green: These are a mix of two primary colors. For example, mix primary yellow and primary red to make secondary color orange.

These 3 primary colors and 3 secondary colors make up the basics of the color wheel.

This is where theory and reality depart - the color wheel should be used only as a tool to understand colors behavior rather than a guide for choosing paints while implementing. The variations are too many for the color wheel to show them all.

For example: Cadmium Red is an orange-red and will have a bias towards yellow. Alizarin Crimson is a blue-red and will have a bias towards purple. So it is not just as easy as buying a "pure red" and a "pure yellow" -- they don't exist.

Developing your Artist's Eye
The process of developing your Artist's eye can take a while. A few people have it intuitively and most have practice. So be patient. At the beginning, you'll be certain you mixed a color perfectly but as you apply it next to other colors or the color you are trying to duplicate, it will look wrong. Trying again and again is the only way for you eyes and brains to start understanding the slight differences and what color is missing a bit more.

What is Hue?
Hue is the easiest to understand: at its most basic, it's art speak for the actual color of a pigment or object.

What is Value?
Value or tone is a measure of how light or dark a color is, without any consideration for its hue. The problem with a color's value or tone is that how light or dark is seems is also influenced by what's going on around it. What appears light in one circumstance, can appear darker in another circumstance, for instance when it's surrounded by even lighter tones. (See picture on right).

What is Chroma?
The chroma or saturation of a color is a measure of how intense it is. Think of it as "pure, bright color", compared to a color diluted with white, darkened by black or grey, or thinned by being a glaze. Variations in chroma can be achieved by adding different amounts of a neutral gray of the same value as the color you're wanting to alter.

Aren't Value and Chroma the Same Thing?
Color mixing would be easier if they were, but they're not. With chroma you're considering how pure or intense the hue is, whereas with value you're not considering what the hue is at all, just how light or dark it is.

Do I Need to Consider Hue, Value, and Chroma Every Time I Mix a Color?
As a beginner painter, yes you do. But the good news is that with experience of color mixing, it becomes easier and less of a systematic process. Initially it's well worth taking the time to consider the hue, value, and chroma in a color you're want to match, making a judgment or decision on each before you attempt to mix the color. You'll waste less paint and not have as much frustration by mixing the "wrong" colors.

Some Color Recipe Examples
Blue Green -1 part yellow, 3 parts blue
Blue Violet - 2 parts blue, 1 part red
Brown - 1 part yellow, 1 part red, 1 part blue
Charcoal - 2 parts blue, 1 part red, 1 part yellow
Citron 1 - part orange, 1 part green
Flesh - start with white and add yellow, red, brown and sometimes blue.
Note: Flesh is the hardest color to describe (as you might imagine) so you will have to experiment with the ratios.
Green - 1 part yellow, 1 part blue
Olive 1 - part green, 1 part violet
Orange -1 part red, 1 part yellow
Pink -1 part red, 1 part white
Red Orange - 2 parts red, 1 part yellow
Red Violet - 2 parts red, 1 part blue
Russet -1 part orange, 1 part violet
Violet - 2 parts blue, 1 part red
Yellow Green - 2 parts yellow, 1 part blue
Yellow Orange - 2 parts yellow, 1 part red

Air Brush or brushes?

For general background colors and surface painting, we use airbrush. Regular brushes can not achieve very fine or translucent coating without leaving brush marks and the fine thickness tapering off merging with the non-restored area is superb. We use Paasche H-SET Series Single-Action airbrush system.

Brushes, however, are essential in duplicated the original design painted on the repaired areas. Choosing the right brush is very important in order to fulfil all quality aspects that should be taken into consideration when planning a retouching project. The original artist brush type and brush stroke movement must be duplicated to create the same effect if invisible repair is required. See Appendix below for more about brushs.

The use of the brush in the restoration practice is more of retouching. The evaluation of brushes for retouching should take into account 4 factors: texture, origin, size and shape of fibres. These factors will define the properties of the brush such as filament retention, shape maintenance, perfect tip, flow control, paint pickup and steadiness of paint release.

The key factors in properly spraying an airbrush are the proper dilution (e.g. Acrylic painted thinning with water) - see more about thinning / diluting acrylic paints for air brushing, operating air pressure, amount of material being released by the airbrush, the distance the airbrush is being held from the surface being sprayed, hand movement, paint thickness nozzle size chosen. For fine lines the airbrush should be held as close as possible to the surface with a small amount of material being released, for broader spray coverage the airbrush should be held 4” to 6” from the surface being sprayed with a larger volume of material being released.

The airbrush will produce overspray. This is the “fuzz” of dots that sprays outside of or around the spray’s desired focal point. If a sharp edge is desired, a masking medium (low-tac masking tape, spray shield, latex paint, etc.) must be utilized when airbrushing.