![\"light_110801_IMG_6570\"](\"http:\/\/ralphnordstromphotography.com\/wordpress\/wp-content\/uploads\/2011\/09\/light_110801_IMG_6570.jpg\" "\\"light_110801_IMG_6570\\"")
<\/a>What color is a cloud?<\/p>\nThe answer is easy?\u00a0 White?\u00a0 Well yes.<\/p>\n
And no.<\/p>\n
You see, we can\u2019t really say anything about the color of an object like a cloud without knowing another important factor.<\/p>\n
So let me ask the question again, \u201cWhat color is a cloud?\u201d<\/p>\n
Again, yes.<\/p>\n And no.<\/p>\n What\u2019s the difference between the two clouds?\u00a0 It\u2019s the color of the light that is illuminating them.<\/p>\n In the first photograph the clouds are illuminate by mid-day sunlight.\u00a0 In the second photograph the clouds are illuminated by the setting sun.<\/p>\n So again, what is the color of a cloud?<\/p>\n Oh, red you say?<\/p>\n Again, yes and no.<\/p>\n As the sun drops farther below the horizon the color it leaves behind changes from golden to red to pink.<\/p>\n So it\u2019s not really the clouds that are changing color but the sunlight that is illuminating them.\u00a0 And it\u2019s the sunlight that is changing color from when it\u2019s high in the sky to when it drops down to the horizon and eventually sinks below it.\u00a0 Why is this?\u00a0 Because the color of sunlight is affected by the atmosphere trough which it passes.<\/p>\n By the way, the sunlight of mid-day is considered to be our reference color.\u00a0 This is our white; the light has not bias or cast.\u00a0 We talk about colors in reference to daylight or, more precisely, mid-day light.\u00a0 If the light is bluish it is considered cool.\u00a0 If it\u2019s reddish it\u2019s considered warm.\u00a0 Enough of that.\u00a0 Back to the position of the sun in the sky.<\/p>\n When it\u2019s directly overhead the atmosphere it passes through is relatively thin, most of which is within the first ten miles or so.\u00a0 But when the sun is low in the sky it passes through much more atmosphere and the blue light is scattered leaving the warm golden rays to reach us.\u00a0 This is what gives us the Golden Hour light we so prize, the hour after sunrise and before sunset.\u00a0 If you would like to read more scientific explanations about this here\u2019s a nice Wikipedia article on Rayleigh scattering<\/a>.<\/p>\n To recap up to this point, the color of a cloud is determined by the color of the sunlight falling on it.<\/p>\n But is that all?\u00a0 Let\u2019s ask the question again.\u00a0 What color is a cloud?<\/p>\n So why is this cloud blue?\u00a0 The sun isn\u2019t shining on it.\u00a0 What is its source of illumination then?\u00a0 Often in my workshops people look at me like I\u2019m crazy when I give them the answer.\u00a0 But it\u2019s true.\u00a0 The blue sky<\/strong> is the source of illumination.<\/p>\n We don\u2019t often think of the sky as a light source but it is.\u00a0 And since it\u2019s blue (at least during the middle of the day) the light it casts on objects is blue.\u00a0 Of course, the sky can also turn golden and red at sunrise and sunset.\u00a0 Why, if you look carefully at those times of day you will even see green in the sky.\u00a0 Don\u2019t believe me? Check it out.<\/p>\n In just a few minutes the sun that is shining on the mountain top in the background will touch the clouds and their color will change.<\/p>\n Same morning, same clouds, different light.\u00a0 Now the clouds have lost their blue cast and are yellowish.\u00a0 They just went from the sky being the source of illumination and color to the morning sun.<\/p>\n Let\u2019s look at another example.<\/p>\n What is the color of a cloud?<\/p>\n But, truth to tell, the light on overcast days is not neutral gray.\u00a0 Sunlight is falling on the tops of the clouds and the light filters through.\u00a0 As it does a little of the reds, yellows and oranges are scattered by the water droplets and the light emerging from the bottom of the clouds is slightly blue.\u00a0 We\u2019ll come back to this when we talk about White Balance in a later post.<\/p>\n So, what color is a cloud?<\/p>\n What\u2019s the lesson to learn here?<\/p>\n I chose clouds as our subject because they take on the colors of the light sources.\u00a0 But all objects take on the colors of their light sources to varying degrees.\u00a0 It\u2019s just that clouds are so obvious about it (because they\u2019re white).\u00a0 I could have used snow just as well except it\u2019s in short supply here in Southern California.<\/p>\n So, lesson number one is the color of the light source influences the color of the object.\u00a0 And lesson number two is that there are many sources of light out there including the sun, the sky, overcast clouds and more.<\/p>\n I\u2019ll leave you with this true story.\u00a0 When my daughter was three I was driving her home from daycare.\u00a0 The sun was just above the horizon and it was a particularly bright and warm sunset (one of the few benefits of California smog I\u2019m afraid).\u00a0 We were driving through a residential area and my daughter exclaimed, \u201cLook daddy, the leaves are red!\u201d\u00a0 No, it wasn\u2019t autumn.\u00a0 We don\u2019t get autumn in Southern California.\u00a0 The leaves were green but the red in the light of the setting sun was so intense that the leaves did indeed look red.<\/p>\n Here\u2019s an exercise for you.\u00a0 Become aware of the sources of light that illuminates the\u00a0 objects around you.\u00a0 Then become sensitive to the color cast they impart on the objects.\u00a0 A good place to start is with the blue sky and the effect it has on the color of shadows.\u00a0 Train yourself so you can actually see that shadows are blue.\u00a0 (Can you explain why?)<\/p>\n Then look for other sources of light such as the sunlit wall of a building.\u00a0 What effect does it have on the color of nearby objects?<\/p>\n As you expand your awareness of sources of light, their colors and the effect they have on the world you will better understand one of the many fascinating properties of light.\u00a0 And you will be able to better utilize this property in creative ways in your photography.<\/p>\n<\/a>Here\u2019s a different answer.\u00a0 Oh, golden you say?<\/p>\n<\/a>Look again.<\/p>\n<\/a>We can\u2019t use sunlight to explain the blue coloring of this lovely fog.\u00a0 And yet it is definitely blue.\u00a0 (Fog is most certainly a cloud, just one that is resting on the ground.)<\/p>\n<\/a>See?<\/p>\n<\/a>On an overcast day the color of clouds is off white or gray.\u00a0 And now the clouds become the light source and impart their gray light on everything.<\/p>\n<\/a>The answer is it takes on the color of the source of illumination.\u00a0 And an important thing to realize is that the source of illumination is not always the sun but can be the blue sky or the golden sky or the pink sky.<\/p>\nColor Exercises<\/h3>\n