The Small Change in Colouring Practice that will Contribute to Reducing Global Warming

Global warming is an emotive issue, regularly the subject of news items and the effect it has on our environment, health, and wellbeing. While there is no “magic” one step fix, the effect can be halted and reduced by the introduction several strategies and colouring plastics, like those used in paints, coatings, and roads, with “cool colours” is one.

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Q: How do colours contribute to global warming?

A: ?A material colour is the perception created by the absorption and reflection of certain wavelengths of visual light. Light is electro-magnetic radiation [EMR] and any that is absorbed by the product also results in warming the product. As well as light in the visual spectra producing the colour we see, EMR is also absorbed in the invisible Infra-Red wavelengths, which does not contribute to the perceived colour, raising the product temperature.

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Q: Is this change noticeable?

A: Darker colours absorb more radiation more than others. For instance, Black is absorbed by EMS across the whole spectra, while conversely white reflects; hence black products out in the sun get noticeably hotter than white ones. [some black plastic products can reach 50C in summer, south facing in the South of England] Infra-Red wavelengths spectra represents 45% of the EMS spectra, so if we can produce our colour in just the visible part but to reflect all wavelengths in the Infra-Red this will make a significant difference to the warming of the product.

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Q: Is this difficult to achieve?

A: The technology is known and understood. At Colourtone we have comprehensive laboratory equipment that can measure the Total Solar Reflection [TSR] and Heat Build Up [HBU] of colours and we can also provide batch identifying certificates proving that each batch is performing in the invisible areas. We can ensure every colour matched has the highest TSR and lowest HBU achievable. All colour matches typically have additional colouring criteria to a matching colour. Food contact suitability, light fastness, weathering resistance, children’s toys, to name a few. To add Infra-Red reflectance to these initial matching criteria for outdoor colour applications is not a big demand. It just requires careful colourant selection to ensure the best possible result and is a responsible response to the global warming concern.

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Q: Is it effective?

A: Colours utilising IRR pigments can offer up to 40% reduction in temperature profiles compared to that of a conventionally formulated colour, resulting in lower service temperatures. Two objects placed in direct sunlight, whose colour appears identical in the visible spectra, can be formulated to have completely different reflectance characteristics in the IR range. The colour designed to reflect the IR radiation will remain significantly cooler than its IR absorbing equivalent under the same environmental conditions.

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Q. Are there any other benefits from applying this technology?

A: There certainly are. Products will experience less warping, distortion, fading, chalking, embrittlement, and failure which result in maintenance savings and improve products with a longer product service life.

Is it not the more responsible approach to the environment to specify the most Infra-Red Reflective match as part of the colour matching specification for new external colours?

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