Different places and different times of day can affect the colours you capture in a digital photograph and all image sensors are designed to reproduce a wide range of hues and tones accurately. From the harsh desert sunshine to the misty rainforest; from sunrise to dusk; indoors and out; your camera should be able to produce pictures that capture the colours and atmosphere of the place and time of day.
Different places and different times of day can affect the colours you capture in a digital photograph and all image sensors are designed to reproduce a wide range of hues and tones accurately. From the harsh desert sunshine to the misty rainforest; from sunrise to dusk; indoors and out; your camera should be able to produce pictures that capture the colours and atmosphere of the place and time of day. However, there are some situations when the automatic settings on the camera struggle to produce the correct colours and tones. The most common involve artificial lighting, which is often biased to one particular colour. Incandescent lights (including halogen lamps) have a strong orange cast, while fluorescent lights are often slightly greenish. You may not notice these colour biases in everyday life but they can affect the way in which our camera reproduces the colours in a scene. The white balance setting is used to make the colours in a digital photograph look natural under a variety of lighting conditions. The auto white balance control on a digital camera works by balancing the colour information from the camera’s sensor to produce an image in which all hues are in equal proportions. It’s usually quite effective under normal daylight, where even landscapes with mostly green and blue hues will still look natural under the prevailing white light. However, with some kinds of artificial lighting, the balance of hues can be skewed and this will influence the appearance of the captured image. Although you may not notice these colour casts when framing a shot, your digital camera’s sensor will record them. The most difficult type of lighting to correct for the auto white balance controls in most cameras is incandescent lighting, which has a strong orange cast. Fluorescent lighting has only slight colour casts, usually greenish in hue. Cloudy skies and open shade can produce cool-looking photos, while electronic flash often has a slight blue cast. Click here to see typical colour casts in simulated pictures.
Manual White Balance Controls Some cameras also let you fine-tune white balance settings along the blue/amber and magenta/green colour bands, using the camera’s LCD monitor to adjust the strength of the colour changes.
Some cameras include controls for tuning white balance settings. Adjustments can be made on two colour axes: blue/amber and green/magenta.
Special Colour Effects A better approach is to ignore the in-camera colour conversions and take all your photographs in full colour. Even the simplest image editors, such as Picasa2, include colour conversion controls. Making colour conversions with editing software allows you to keep a copy of the full-colour photograph and, at the same time, experiment with a much wider range of colour conversions on copies of your original photographs. Black and White conversion of a colour photograph in Picasa2.
The best monochrome prints also start off as full-colour digital images. Images that need editing should be edited in your editing software before they are converted to monochrome. Assuming all the tones in the colour original are correctly balanced, the simplest way to convert the image to black and white is to open the colour adjustment control and select Adjust Hue/ Saturation then move the Saturation slider back to -100. Make sure you save the file with its own file name so you don’t over-write the colour original. Image editors generally provide a much wider range of colour effects than those offered in digital cameras. Graduated colour effects, like the one shown above, are never found as incamera conversions.
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