The Science of color

Listen in on this topic deep dive…

The colour is bright enough, why aren’t the fish striking at it?

Some anglers ask themselves this all the time. If you do not, you might want to consider asking it sometimes when you are having a really slow day. Just because the color looks good to us on the surface, does not mean it is going to look good underwater to fish because water changes color drastically. To fully grasp this, we have to understand the science behind light and how light is affected by water. This may not seem important, but how light acts underwater determines how well a fish can see the color of your lure.

The Science
We will start with a very basic physics lesson. Most people are aware that white light is really made up of different colored lights, as known as wavelengths. When these wavelengths strike something, some colors are reflected and some are absorbed. The wavelengths that are reflected are what our brain uses to determine the color of an object. A white object reflects all wavelengths.

On the opposite end of the spectrum, an object that absorbs all color is seen as black. Between the two extremes most objects reflect and absorb different wavelengths and different amounts of wavelengths to get the color we see. For example if you look at a red car the wavelength reflecting off it would be red, all other wavelength colors are being absorbed.

Color underwater
White light passing through perfectly clear water will lose its wavelengths at different depths. The longer wavelengths like reds and oranges will be the first to be absorbed. The shorter wavelengths like blues and purples will be the last to be absorbed. In laymans terms, brighter colors will be absorbed faster while darker colors will still be seen deeper in the water.

Reds go first, followed by orange, yellow, green, blue, indigo and violet. This occurs on a clear summer day however. For example if you were trolling a red lure at 15 meters (45 feet) it would be seen as black since the wavelength was absorbed much higher up.

Color and Water Clarity
In the deep waters of lakes, oceans and rivers there are two main factors that will effect how well light will penetrate the surface of the water: color and clarity.

Color is not referring to the color of the lure in this case. It is referring to the actual color of the water. Water can have its color changed by any dissolved materials, especially organic acids from decaying marine or land life. Think of what happens when you aid a drink mix to clear water. You can still see through the water but it is now colored. Mind you the coloring will not ever be as drastic but it is the same kind of principle. Color will reduce light penetration and will affect blue and green wavelengths, making your blue, green and purple lures disappear from sight.

Clarity refers to how many suspended particles or matter, like algae and slit, there is in the water. The more particles, the more light will be scattered because of them. The longer wavelengths like red, orange and yellow are affected the most.

What the water looks like on that particular day will determine what color lure you should be using.

Timing and Color
If all this was not enough to remember, things get even more complex during different times of the year. Season cycle and turn-over can affect how well a lure is seen. In a lake with a lot of algae bloom, light penetration is reduced because of the algae population. Since algae bloom the most in autumn, all wavelengths are affected by the lack of light penetration, especially the red, yellow and orange wavelengths. Once the algae start dying out in the winter due to the cold, light penetration is better.

It may seem odd that the color of your lure will change depending on the time of day, but to make this easy to understand, think of how we see colors on a clear day in the afternoon compared to a cloudy day at dusk. On a clear day there are fewer airborne particles and gases in the air so the sky is blue. As the sun sets light will travel through more gases and airborne particles until the bright blue fades away and we see reds, yellows and oranges. Then these three wave lengths will drop off and be replaced by darker blues and purples. Time of day will also affect how we see the color of an object.

Why is that important? Because water not only copies what is happening above the wave line, but it also magnifies this effect. Meaning, the bright blue wavelengths will disappear even faster under water then above water.

Other influences can also affect color. If there is a ripple on the surface of the water it can cause light to scatter more and reduce light penetration in the water. Pollution in the water and in the air can also affect light penetration and therefore affect the color of your lure.

No matter what you do, always remember that sometimes a subtle change, like color, on a really slow day can bring you a better catch. With all this information about color in mind, selecting the right color for the time of day, day of the year and body of water should now be a breeze.