Light Reflectance Value & What It Means For Your Colour Choices

05Sep
Light reflection value for paint color

Selecting colours for your strata, commercial or residential painting in Sydney or anywhere in the world can be tricky when you consider just how much there is to think about. Not only can it determine the look, feel and vibe of a particular room, but the colours you choose also go a long way in influencing how much light is reflected around, which makes a huge difference. In other words, both colours and the surface textures equally affect the amount of light reflected through the surfaces. And the more light reflection means higher Light Reflection Value or LRV. The less light reflection is, the lower the LRV.
Thus LRV is one of the most important factors to consider while choosing a paint colour. In this article, we are going to explore some of the fundamental aspects of Light Reflectance Value and its effects on both interior and exterior paint colour choices.

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So what exactly is LRV?

 Light reflectance value (LRV) refers to the amount of light that is reflected off or absorbed by the surface of a wall or ceiling. Different colours and shades have different expected LRVs, meaning that some will better circulate the light that enters a room, which affects the atmosphere and mood of the room considerably.

LRV chart

 

Theoretically, on one of the LRV scale, we have absolute black and the other white, with colour shades that we use in homes laying somewhere between the two extremes. In practice though, the blackest of blacks register 5%+ LRV while the whitest whites don’t come close to 100%. Architects specify a certain LRV in terms of providing a distinct colour range for projects that contain multiple units.

What is LRV used for?

It goes without saying that home decorating is largely intuitive and based on feel. But matching colours effectively can also have a scientific basis when you consider the LRV of the paint colours you are using. In fact, many professionals including interior designers, colour consultants, painters, decorators and architecture will consider at LRV as a means of calculating the expected light in a room.

 

LRV is important for other non-aesthetic reasons too. Choosing a colour with a high LRV in a room or corridor will mean it has higher visibility and may not require as many lights, for example. More often than not, buildings that require high visibility will need to fall in the 60-70% LRV range.

If you think of hospitals, which serve a very practical service, most surfaces are painted with high LRV shades, and this ensures the highest possible visibility, rather than looking to create a comfortable atmosphere for example.

How to measure the right LRV to choose painting colour?

Any painting colour’s approximate LRV implicates the amount of visible light the colour itself will reflect- which has direct impacts on the energy consumption of the building. For instance, black’s light reflectance value is 0% as it absorbs all the light, causing dark and hot building surfaces. Which means to block or darker colour will helo the house stays warmer in cold climates. White, on the other hand, has the light reflectance value of 100%, which means less sub heat absorption during humid climates. The rest of the colour palettes reside within these two variables. And meeting these LRV specifications is crucial to keep the integrity of a building’s architectural elements in check. So it goes without saying that keeping different aspects like building architecture, building location, topography, climate change etc. in mind, you need to measure the right LRV for both the interior and exterior of your building.

While evaluating building colour and finish options, industry-standard 70% Light Reflectance Value contrast between sign text, background colour and lightness difference is an ideal metric to follow.

Here’s how the values can be calculated-

Contrast = (B1 – B2) x 100 / B1

B1 = light reflectance value (LRV) of lighter area
B2 = light reflectance value (LRV) of darker area

In general, the LRV is measured by using a spectrophotometer, which is expressed as a number without units. This LRV number is indirectly associated with the light reflection percentage. Nowadays, the LRV rating index of different colour palettes is provided with most colour chips by major paint supplier brands.

What does this mean for homeowners?

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If you’re doing a DIY paint job or redecorating some rooms in the house, checking out the LRV can be a smart move and ultimately a good starting point. You may be drawn to particular shades or a particular colour palette, and ensuring that it falls within a reasonable LRV is important. As the LRV charts are usually seen on the back of paint buckets when you buy them at the hardware store, this can already give you some idea of how the much light will be seen in the room. When you’re comparing different shades, keeping an eye on this can help you make an informed decision.
For more households, around 50% is what you should be aiming for, though bathrooms will often be higher.

What are the recommended LRVs for exterior paint?

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Now let’s talk about both light and dark exterior painting colours depending on their LRV. Darker exterior colours tend to absorb more heat and energy from the environment, which leads to substrate movement that can easily break the chemical bond between previous coats and the substrate. So, it’s crucial to choose light painting colour palettes with higher LRV (closer to 100) if the residence is located in a humid climate. Light colours improve the building’s exterior film durability by reflecting more light and absorbing less heat and energy.

Dark exterior paint colours with low LRV (closer to 0) in a cold climate can help hide or camouflage exterior surface flaws and imperfections with more visual exposure. Dark colours also absorb light and keep your house warm and cosy.

How is LRV connected to the house efficiency?

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With the help of Colour consultants, architects, and designers, if you pay close attention to the colour LRV while choosing your house interior and exterior paint colour, it will benefit you choose the right lighting fixtures for you as well. From a sustainability point of view, the right LRV supported paint colours help you reducing the standard number of artificial lighting fixtures, which create energy-efficient, eco-friendly household. Moreover, house surface colour with a higher LRV supports a better lighting plan with a proper visual ergonomics that helps to propagate the most out of daylight throughout the space too.

LRV is a good guideline when thinking about the colour selection in your home. Whether it’s for a DIY or professional job, choosing the right combination of colours is never particularly easy! But having a clear idea of how your chosen paint colours can affect the level of light in your home can make your job easy and can give your home the perfect look!

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