Designers seek architectural colour that combines form and function
Colour, form, space and light are principal components of an architectural project, but colour is the one element that most affects the others. Selecting the right colour for a building project can be a daunting task. Colour has a profound effect on the human experience and, in particular, on users of the built environment, where we live, work and play. It also plays a dramatic role in changing and improving the aesthetic appeal of particular areas.
Just as colour is consistently a key selling feature for building components, whites, beiges, bronzes, metallics and greys have remained the leading colour choices for many years. One of the things that designers and building owners seek is a building that does not appear dated years down the road. As a result, colour choices tend to be more conservative. Yet, definitive colour trends are taking place, as consumers and the design industry increasingly desire to express creativity. This is accomplished by re-evaluating the power of architectural colour, looking to more colour trends and bringing bolder colour choices to their projects.
This poses a unique opportunity for high-performance architectural coatings, as some bright, eye-catching colours can be difficult to achieve, and selecting the wrong colour can mean failure.
In today’s world of ever-increasing expectations, the coating manufacturer faces the tough challenge of pleasing the customer and providing a quality product that will last. One key ingredient that can make or break a coating is the pigment, which provides a coating’s colour. The pigment component in any formulation can either enhance or degrade the overall performance of the protective colour coating. In architectural building components, the chemical resistance of the pigment is crucial. This sometimes restricts colour spaces that can be achieved. No matter how well a coating is made, certain colours are more affected by the outside environment than others, for example bright colours such as yellows, oranges and reds.
Pigments: Inorganic v. Organic
A pigment changes the colour of reflected or transmitted light as a result of wavelength-selective absorption. Their role must include both colouration and function. Pigments are either inorganic or organic in composition. Sometimes, both types must be used to achieve a certain shade or colour.
Inorganic pigments are manufactured from mineral compounds that consist mainly of complex metal oxides and have superior colour stability, heat and chemical resistance. Colours made from inorganic pigment are less bright, such as beiges, browns, tans and other earth tones.
Organic pigments are carbon based and are often made from petroleum compounds, but they have a low resistance to fading, and low heat resistance. They allow UV and oxygen to penetrate, breaking the chemical bonds, and have less hiding power. Colours made from organic pigments have a very bright, vivid appearance. These are sometimes known as cleaner or purer colours.
The following table gives a comparison between inorganic and organic pigments.
Every day, Valspar colour technicians are challenged to select affordable pigments for coatings required for durable applications. Their choices are restricted due to environmental and performance concerns. This limits colour space and warranty options, especially if a high warranty is required. In general, paint manufacturers will blend inorganic pigments with premium resins (PVDF), and organic pigments with less-expensive resins (polyesters).
Warranty: How does colour affect warranty?
To begin with, each architectural project must be analysed in terms of its own particular situation, function and need. With each project, one needs to ask:
- What is the application’s end use?
- What is the application’s environment? For example, percentage of direct sunlight.
- What are the performance requirements?
Answering these questions will help determine the coating’s formulation and the warranty that can be provided. Not all pigments are suitable for every application. Pigments for exterior, high-performance architectural coatings require top-end products with outstanding properties - especially heat resistance. Colour warranties are based on the percentage of organic v. inorganic pigments used to create the final colour.
The Valspar standard warranty looks at the film integrity, chalking and fading of a coating. Film integrity is determined by the resin system used: PVDF, SMP or polyester. Chalking and fading is caused by the breakdown of the pigments. Chalking, the appearance of a white powder, is the result of a breakdown of carbon bonds by ultraviolet (UV) light. The pigment should be a UV absorber or reflector. Fading is caused by a breakdown of the pigment itself, measured in Delta E (DE) variations.
Here are a few examples of different warranty options for Valspar’s Fluropon® (PVDF) product, in various colours, with maximum exposure on a metal roof:
It’s clear in this example that pigment selection was the deciding factor in the warranty consideration of the coating. Additionally, we take end use into consideration. This example called for maximum exposure.
What about adding a clear coat? A clear coat can indeed improve some of the borderline bright colours and is critical for metallic colours using aluminium pigmentation. For a metallic colour, if the colour exceeds a certain level of aluminium pigment, it requires the use of a clear coat. This top coat keeps the aluminium from discolouring when exposed to certain chemicals in the environment. Similar results can help bright colours, while the colour fading and chalking resistance of some organic pigments can be improved by using a clear coat. Within a warranty, the colour fading (5.0 DE) typically does not jump from five years to the standard twenty years, though a move from five to ten years is not unheard of. This is decided on a case-by-case basis.
No matter what colour you are trying to achieve, Valspar has a strong tradition of innovation in the development of colour, as well as dedicated resources to assist our clients in making the right selection. Protection of the architect’s vision matters above all else. Valspar coatings will make sure that your vision ages beautifully.
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