Black clothes absorb light differently than lighter colored clothes. The color black absorbs light, while lighter colors reflect more light. This causes black clothes to heat up more in the sun. There are a few key factors that determine how much light is absorbed or reflected by clothing:
Color
The main factor that determines how much light is absorbed or reflected is the color of the fabric. Black absorbs the most light because it contains no hue and low brightness. White reflects the most light because it has high brightness. Other dark colors like navy blue also absorb a lot of light, while lighter colors like yellow and light blue reflect more light.
Fabric composition
Certain fabrics naturally absorb more light than others, even in the same color. For example, cotton and linen tend to absorb more light than synthetics like polyester. So a black cotton t-shirt will get hotter in the sun than a black polyester t-shirt.
Weave
The weave of the fabric also impacts light absorption. Tightly woven fabrics block more light from passing through the gaps between threads. Loosely woven fabrics allow more light to pass through. So a tightly woven black shirt will absorb more light than a loosely woven one.
Thickness
Thicker fabrics absorb more light because there are more threads for the light to interact with. A heavy black wool sweater absorbs more light than a thin silk shirt in black.
Dye composition
The type of dye used to color the fabric also affects light absorption. Pigment dyes physically block light absorption. Fiber-reactive dyes chemically bond to the fibers to absorb light. So black clothes dyed with fiber-reactive dyes absorb the most light.
Finish
Certain fabric finishes can increase light reflection. For example, glossy finishes like glaze increase surface reflection. Matte finishes absorb more light by diffusing reflection. So a black shirt with a glossy finish will stay cooler than a matte black shirt.
How the properties of black affect light absorption
The reason black absorbs so much light is because of its inherent properties:
- Black contains no hue, meaning there is no color reflection.
- Black has low brightness, so it does not reflect much visible light.
- Black objects absorb almost all visible wavelengths of light evenly.
On the light spectrum, black absorbs most visibly while reflecting very little. This causes almost all the light that hits black clothing to be absorbed as heat energy.
Percentage of light absorbed by different colors
Here is the approximate amount of visible light absorbed by different colored fabrics:
| Color | Light Absorption |
|---|---|
| Black | 95-98% |
| Navy | 90-95% |
| Red | 50-60% |
| Green | 30-40% |
| Yellow | 5-15% |
| White | 0-5% |
As the table shows, black absorbs almost all visible light, while lighter colors reflect more and more light.
How light absorption affects temperature
When clothing absorbs light, it converts that light energy into heat. This causes black clothes to heat up much faster than lighter colors.
According to physicists, a black car parked in the sun can reach temperatures over 130°F-150°F. This same effect applies to black clothes. Darker colors can raise surface temperatures by up to 50°F compared to white objects.
This concept is known as the albedo effect. Surfaces with low albedo (light reflection) absorb more radiation and convert it to heat. Black has an albedo of 0.04, absorbing 96% of light. White has an albedo of 0.90, reflecting 90% of light.
Properties that cool clothes
There are some properties that can help clothing stay cooler in the sun:
- Loose weave – Allows more airflow through the fabric
- Natural fibers – Absorb moisture for evaporation cooling
- Light colors – Reflect heat from the skin
- Thin material – Prevents heat buildup near the skin
- Breathable fabric – Allows sweat and heat to escape
So a loose, light colored linen shirt will stay much cooler than a tight black wool sweater. The linen allows air circulation while reflecting more light. The wool traps heat near the skin.
Impact on skin temperature
Wearing black clothing in hot weather can raise skin temperature and body heat. The black fabric absorbs solar radiation and converts it to heat near the skin. This can lead to overheating.
One study found that skin temperature was 5°F higher when wearing black clothes vs white clothes in sunlight. Core body temperature was 0.9°F higher in black outfits.
The rise in skin temperature can make black clothing uncomfortable on hot sunny days. The trapped heat can cause sweating and dehydration.
UV protection
While black clothing absorbs more visible light from the sun, it can also block ultraviolet (UV) rays. UV rays have shorter wavelengths that can damage skin.
Dense, darker fabrics provide effective UV protection by absorbing these rays before they reach the skin. Black garments rated UPF 50+ block 98% of UV radiation.
So while black absorbs more heat, it also shields the skin from UV damage compared to lighter colors.
Nighttime temperature
At night, black clothing can actually help keep you warmer because it absorbs heat from the body. Black emits less infrared radiation from the skin compared to lighter colors.
So black clothing traps radiant heat close to the body after sunset. This helps maintain a warmer microclimate around the skin at night.
Conclusions
In summary, black clothes do absorb more visible sunlight than lighter colors during the day. The high light absorption and low reflection of black fabrics causes them to heat up significantly in the sun.
Lighter, looser fabrics in colors like white, tan and light blue will stay cooler in hot weather. They reflect solar radiation and allow heat dissipation.
But black clothing provides excellent UV protection by absorbing these rays. And at night, the heat absorption can help keep you warmer in cold temperatures.
So while black absorbs more heat during the day, it also has advantages for sun protection and nighttime warmth. The key is choosing the right fabrics for the conditions to stay comfortable.
