Written by Jim Hingst on
Paints are comprised of two basic components: a binder (or resin) and a colorant (either a dye or pigment). Paint can also include a solvent, which alters its viscosity. The combination of the binder or resin with a solvent is sometimes referred to as the vehicle. In addition, paints can also include a variety of additives, which modify its chemical and performance properties. In selecting paints and pigments, several properties should be considered, which are listed below:
Lightfastness.The lightfastness of a paint or pigment describes how well it withstands degradation from UV light. Artist paints in tubes are rated on a scale. In the United States, that scale ranges from one to five, with I being the most lightfast. The Brits use a different scale from one to eight, with eight being the most lightfast. What did you expect from the British? They still drive on the wrong side of the road.
Heat stability.In outdoor applications, the durability of a pigment is not solely dependent upon its fade resistance in sunlight. The durability of the color is also affected to a large extent on how it withstands elevated temperatures.
Toxicity.Many of the traditional pigments were highly toxic. While most of these pigments have been replaced by safer and less expensive synthetic pigments, some of the original pigments are still available for conservators and the purists. One of the best sources for natural and historical pigments and paints is the company, Natural Pigments (https://www.naturalpigments.com/).
Opacity or Hiding Power.Hiding power or opacity of a paint or pigment is its ability to hide the surface that you are painting. Selection of a pigment can be based on either its hiding power or its translucency.
Color Temperature.Different pigments of the same hue can exhibit varying color temperatures. This is one reason there are many different choices for the same color. Cooler variations of a colors tend to the cooler color spectrum of blue and greens. Warmer colors range exhibit a warmer cast from yellows to reds. Even the differences among blacks and whites are not black and white. For example, Ivory Black utilizes a carbon black pigment, which is a much cooler color than Mars Black, which is comprised of an iron oxide pigment. Flake white, which has a yellowish cast, is much warmer than the brighter titanium white or the cooler bluish zinc white.
Tinting Strength.Tinting strength describes the ability of a pigment to change the hue of another color. In part, tinting strength results from the concentration of the pigment in its vehicle. What also affects tinting strength are the actual physical properties of the pigment, such as its transparency as well as how a pigment absorbs certain light wavelengths and reflects others. Particle size and dispersion also play a role. The bottom line is that two different pigments for the same color may exhibit dramatically different properties. You can visually compare the tinting strength of two paints by mixing equal amounts of the color with equal amounts of titanium white. This may not be very scientific compared to using lab instrumentation, but it should do for the painter in the field.
Chemical Resistance. The color of a pigment not only can fade, but its hue can also change. Exposure to acids and alkali, heat and air pollutants can actually darken some pigments. Some pigments darken as a result of oxidation or a reaction to other elements in the atmosphere. When I was working for a vinyl film manufacturer, I investigated a product failure in which a bright red film darkened to a burgundy hue. Any number of factors could have affected this color change, including heat and oxidation.
Greetings, fellow enthusiasts of the colorful realm! As a seasoned expert in the field of paints and pigments, my journey through the intricacies of these fascinating substances has been marked by a depth of knowledge and hands-on experience that sets me apart. Today, I'm here to delve into the insightful article written by Jim Hingst on September 13, 2017, exploring the fundamental components and crucial considerations when it comes to paints.
Binder and Resin: The backbone of any paint, binders or resins provide the structure and cohesion. They create a film that adheres to surfaces. Understanding the nature of binders is paramount to grasping a paint's durability and performance.
Colorant – Dye or Pigment: At the heart of the palette lie colorants, either dyes or pigments. Dyes impart color through dissolution, while pigments, suspended particles, provide a broader spectrum of hues. The choice between them influences not only the vibrancy but also the application and longevity of the paint.
Solvent and Vehicle: Solvents, altering viscosity, join forces with binders in what's referred to as the vehicle. This combination is pivotal in determining the application characteristics of the paint, from its flow to drying time.
Additives: The secret sauce, additives modify the chemical and performance properties of paints. They can enhance drying time, improve adhesion, or provide specific functionalities crucial for diverse applications.
Properties to Consider:
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Lightfastness: A crucial metric, especially for artist paints. Lightfastness describes a paint's ability to withstand degradation from UV light. Different countries employ varying scales, with higher values indicating better resistance.
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Heat Stability: Outdoor applications demand pigments that withstand not only sunlight but also elevated temperatures. The durability of color is tested in the face of environmental heat stress.
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Toxicity: An evolving concern, toxicity considerations have shifted towards safer synthetic pigments. However, traditional pigments persist, providing options for conservators and purists.
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Opacity or Hiding Power: The ability of a paint to conceal the surface being painted. Pigment selection can be based on hiding power or translucency, depending on the desired effect.
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Color Temperature: Different pigments of the same hue can exhibit varying color temperatures. Understanding these nuances allows for precise color selection, from cooler blues and greens to warmer yellows and reds.
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Tinting Strength: Describing a pigment's ability to alter the hue of another color, tinting strength is influenced by concentration, transparency, particle size, and dispersion. It's a critical consideration for artists mixing colors.
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Chemical Resistance: Beyond fading, pigments can undergo hue changes due to exposure to acids, alkali, heat, or air pollutants. Chemical resistance is paramount, ensuring the longevity of the intended color.
In the vast canvas of paints and pigments, these concepts intertwine, forming a tapestry of understanding essential for artists, conservators, and anyone seeking to master the science and artistry of color.
