Light and Color

Light Reflectance Value

Have you ever noticed how the color of your house can look different at different times of the day? Or how the walls of a room may seem warmer on a sunny morning and cooler at night when the lights are turned on? The way that the human eye perceives color involves several factors, but the primary factor is the Light Reflectance Value (LRV).

The LRV for a paint color can be found on color chips and fan decks at your local paint store. It’s a two-digit number that corresponds to the percentage of light reflected. Think of it this way, white reflects light and black absorbs light. A bright white paint will have an LRV of 85% and a pure black paint will have an LRV of 5%.  A higher LRV means a higher amount of light reflected.

Fan Deck with LRV for Various Colors

LRV is used by designers, color consultants and painters in the design of both interior and exterior spaces. Certain colors enhance the quality of lighting and others reduce the intensity. In a warm climate such as the Outer Banks, higher LRV colors might be used on the exterior to reflect sunlight and reduce energy costs. Conversely, in cold climates darker colors may be used to absorb sunlight.

The Impact of Sunlight

The way that sunlight changes through the course of a day is self-evident. Photographers are particularly aware of this. Morning sunlight is warmer from the perspective of color. It is more yellow. My mid-day, the sunlight develops a bluish cast. By late afternoon the sunlight is warm again, favoring red. Seasonally, Winter sun is cooler/bluer than it is in Summer.

Photo: Warm Colors Enhanced by Afternoon Sunlight

Artificial Light

Most indoor spaces rely on artificial light to supplement or replace natural light. The three types of artificial light found in most homes are incandescent, halogen, and fluorescent. Incandescent and halogen lighting are warmer. They enhance reds and yellows, so if you want a blue wall in a room with incandescent lighting, for example, you would tone the paint with a little red. Fluorescent lighting is cooler and enhances blues and greens.

Photo: Incandescent Lighting Enhances Warm Colors

 

Combinations

With most interiors, there are multiple combinations of light in play. The numberof windows in a room affect how much natural and artificial light are present at certain times, but you also need to consider which direction the windows face. In a room with southern exposure, you get more direct light. If the windows provide eastern exposure, you have more morning sun, while western exposure provides more afternoon sun.  Northern and western exposures provide cooler, bluish tones and southern/eastern exposures provide warmer, yellower tones.

Other Considerations

Other elements in a room can also affect your color perception by reflecting additional tones. Flooring, drapes, mirrors and area rugs can reflect a different color cast in certain lighting. For example, a red oak hardwood floor with direct sunlight through a window will enhance the warmth of a yellow wall. Sheen is normally chosen for its durability and hiding power, but it can also impact the perception of color by reflecting additional light. Higher gloss paints are typically used to draw your attention to detail on trim. Walls use flatter sheens because you don’t necessarily want to draw attention to a wall.

Summary

The LRV of a color lets you know how much light will be reflected on a painted surface. Colors and sheens can be selected or modified to reflect the quantity and quality of a room’s light sources. The objects and décor of your room can also influence how your eyes perceive a color. When selecting paint for your next project, try painting a 12” x 12” piece of cardboard or drywall. View the painted sample in different lighting conditions and in different areas of the room.

Terminology

To avoid confusion, you may want to familiarize yourself with these color terms.  

Tint: a color that has been lightened by adding white

Shade: a color that has been darkened by adding black

Tone: a color that has been modified by adding black and white

Chroma: brightness or dullness based on the purity of the color

Warm Colors: reds, oranges, yellows

Cool Colors: greens, blues, violets

Paint Problems - Peeling

The Paint Quality Institutes defines peeling as "loss of paint due to poor adhesion." Peeling can involve multiple coats and often begins with the original coat of paint. 

 

Photo from the Master Painters Institute

Some possible causes of peeling paint include seepage of water or moisture through uncaulked joints, failed caulking, excess moisture escaping through the exterior walls, inadequate surface preparation prior to painting, the use of low quality paint, or applying paint to a wet surface. In all cases, a repainted surface is only as good as the original coat of primer and paint.

While it seems intuitive that "more is better" when it comes to the number of coats of paint that your painting contractor proposes, there is a limit to the number of coats that a surface can support. As the paint thickness builds up over time, and the coatings get older, they lose their flexibility.

The Outer Banks is prone to extreme fluctuations in humidity which can cause the painted substrate to expand and contract. When the paint film is no longer flexible enough to move with the surface cracking or flaking of the coating usually results.

It is not uncommon to put a coat of paint on a surface that appears sound only to have many layers of
paint peel away. At this point, the necessary preparation for a repaint changes.

Photo from the Master Painters Institute

Peeling paint can be remedied by removing all loose paint with a scraper or wire brush after power washing. Any rough surfaces are then sanded and all bare wood is primed before recoating. This is generally the first course of action.

 

In extreme cases where the original coat of paint is failing after multiple repaints, the peeling areas should be stripped to remove all of the old coating, even where it does not appear to be peeling. This is especially true in the case of cedar shakes. Often times this is expensive, but if it is not done properly, a new paint job will likely continue to flake and peel. 

 

The time involved with scraping, sanding, and wire brushing can vary from 35 to 100 square feet per man-hour. It is impossible for anyone to know how long it will take to properly remove peeling paint, which is why most reputable painting contractors will bid the work as an allowance item.