Deep blue skies add a touch of magic to landscapes. They convey a sense of purity and rightly so. A clear blue sky can add a beautiful backdrop to many compositions and sometimes provide the necessary breathing space to the main elements in the composition.
(Monument to the three brothers Kyi, Schek, Horyv and their sister Lybid, founders of Kyiv – photographed using a simple compact digital camera)
There are various methods to achieve deep blue skies. Consider the following methods when you want to achieve dark blue skies in your compositions and also try combining them.
These are the first and foremost filters that come to any photographer’s mind when considering deep blue skies. These filters permit only one plane of light waves to pass through which effectively prevents the scattered light from passing through. This deepens the color of the sky. Maximum polarization is achieved at about ninety degrees from the sun. So if the sun is at the horizon then the area where the polarizer will work the most will be an arc starting at ninety degrees from the sun on the horizon going up to almost at the top of the head and crossing over to the other end on the horizon which happens to be again at about ninety degrees from the sun. With extremely wide angle lenses this effect may look unnatural though, so be careful. (Polarizing Filters)
Graduated ND Filters
Nothing works better than graduated ND filters for darkening the sky. The advantage of graduated ND filters is that they retain the overall hues of the skies. The fine blending of the ND area with the clear area makes them practically perfect. There are some problems with these though. Too small an aperture will sharpen the demarcation of ND filter and the gradient will become noticeable. Secondly, if there is any structure in the foreground that extends all the way into the sky region then the upper half of that structure will also turn dark.
Some pitfalls to avoid while using ND filters for darkening the sky – Do not use very small apertures (large f-numbers) and do no align horizon to the gradient. The filter should ideally be tilted slightly for a more natural looking effect. (Neutral Density Filters)
Do not consider any other graduated colors for darkening skies. I have seen many beginner photographers use graduated blue filters but these may turn out to be counter-productive. Most of these shades look artificial.
Clear blue skies are seen when there is almost no atmospheric dust or haze. So after rains or snow when the clouds clear up, the sky appears really blue. For the same reason, areas which are still untouched by humans have clear blue skies. In periods of high humidity, skies are usually clearer than when the weather is dry. Due to the atmospheric dust, the sunsets turn red. (Time of the day) Though we may not notice it but this information gets processed by our minds instantly. All photographs with clean blue skies instantly convey a sense of purity and freedom from pollution.
Bright foreground subjects
Cameras have a limited range of brightness that it can capture without letting the bright areas blow out and dark areas turn black. This limited exposure values (EV) range is useful for achieving dark skies as well. If the foreground subject is brighter than the sky, metering for the subject will automatically darken the sky. Did you ever notice that all the picture postcards of tourist destinations which have some sort of monument, show the monument in a manner that the sunlight falls on it. Sometimes if the monument is light in shade, the sky in the background can appear really really dark.
(Church in Goa – Bright white building is lit by sun and exposing for the building while retaining the texture in the walls, deepened the sky color. This was further enhanced by the use of polarizer and while post-processing)
Tricks with the color wheel
Another way to achieve dark skies is to play around with the color wheel. Use yellow to red colored filters while capturing the image and reduce the color cast in post-processing. Color filters act by cutting down light in the opposite side of the color wheel. Yellow-red filters reduce the amount of blue light reaching the sensor and thus darken the skies. Since they are colored by themselves, the pictures take an overall color-cast which thus has to be removed. With black and white, this is not required for obvious reasons. (Red Filters (and other colors))
Graduated ND filters can also be added in post-processing or the brightness of the sky can be reduced by using Curves tool (Curves Tool at your service). These methods also give good results but it is very easy to go overboard with these settings. So be careful if you are doing this on your favorite photo-editor. Another thing to consider is the saturation. Though increasing the saturation may transform the sky appear bluer than before but in true sense this is increasing the brightness of the sky as well. The increased saturation can therefore shift the focus in the photograph to itself. If you are planning to increase the saturation of the sky, then combine it with some reduction of the brightness of the sky so as to maintain the impact in the overall photograph.
Some more points to consider-
- When using Polarizer and a Graduated ND filter together, keep the Graduated ND filter closer to the lens. It should be mounted before a polarizer. If you happen to have rectangular ND filters and round polarizers it may be difficult but that is how things should ideally be.
- If there are scattered clouds in the sky and the purpose is to emphasize those clouds then a polarizer works better since it does not darken them. A graduated ND filter will darken the clouds as well.
- Instead of darkening the sky to the deepest shade, consider it as a contributing element to the whole composition. Sometimes a light sky works better than a dark blue sky in some compositions.
- Clean and plain blue sky may at times look very bland. The same sky with scattered clouds can add a completely different character to the photograph.