Sunday, 11 November 2012

Photo Contrast & Brightness For Enhancement

Photo Contrast

The terminology contrast has altogether different meaning in black and white photography and color photography. In black and white photography, the various elements in the picture have different shades of gray in black to white scale. A maximum contrast can be obviously between an element having a black tone and another having white one. There will be many combinations in between. This is also called tonal contrast. 

In color photography, color contrast is due to opposite characteristics of color (warm and cool) in main elements of the photo. Generally speaking colors like red, yellow and orange are considered warm colors whereas blue, cyan and green are considered cool colors. A cool color accentuates the warm color and vice versa. The cool colors gives a feeling of receding and warm color gives the feeling of approaching when referring to the photo elements. Nature abounds in cool colors comprised of blue sky, the green foliage, the gray rock and hence serve as best back drops in any frame. In context of the photo editor, the measure of photo contrast means, the difference of brightness between darkest (shadows) and highlight (well lit )areas.

Coming to Microsoft Office Picture Manager, one opens the file and clicks edit…, then clicks the Brightness and Contrast and is ready to edit the photo for increasing or reducing contrast. If MOPM is default photo editor, double clicking on photo will also open the window for photo editing. A few frames are added for demonstration purpose.

Frame 1

In this frame a shot from a shikara in Dal lake shows a wooden building with shops on ground floor. The wood texture of upper floors looks flat and the shop signboard letters do not look crisp. 

An increase of 40 points or + 40 on contrast scale makes the photo looks much better in terms of color tones. The letters on the signboard looks crisp and clear. 

Frame 2

Following is a photo taken from a resort in Patal Bhuvaneshwar, Uttarakahnd. There is not much difference of contrast between shaded areas and sunlit areas. 

By increasing contrast by 30 or + 30 on contrast scale, the shaded areas become more dark compared to well lit areas and enhances it.

Frame 3

A typical shot of a Leh Palace with cluster of dwellings around it, offers a lot of dark shaded areas. In the bright sunlight, the photo contrast is high. 

The same photo is given a reduction of 20 points or – 20 on contrast scale. The photo does not lose much of sky color but the shaded areas are less dark or more lit offering less contrast to the overall picture. 

Frame 4
Following is temple view at Auli, Uttarakhand. The photo being shot diagonally against the light, the temple wall in the frame is in shade. The details of windows are not clear.

After decreasing contrast by 20 points or –20 in photo editor contrast scale, the wall details including windows are clearer as shown below.

A note of caution: Both the process of increasing or decreasing contrast has to be done carefully to meet the objectives of the photographer. Giving more contrast may render more dark spots and on the other hand less contrast may mean the photo looks flat.  

Photo Brightness
Some photos require photo editing like increasing or reducing brightness.

As usual one opens the Microsoft Office Picture Manager or any other photo editor. One can double click on the photo to be edited or import it separately into the editor frame. On top menu click editing…, a side menu appears. Click on Brightness and Contrast. Two scales appear, one for brightness and another for contrast. One can move the cursor on plus side or minus side on brightness scale for the desired result. For finer corrections, one can use up and down arrows, which give numbers for brightness comparison. Some demo frames are added as follows. 
A photo may be under-exposed so overall the photo appears darker. In some photos the color tones will be looking garish. In such instances increase in brightness does help.

Frame 1
This frame shows portrait of a Langur. If one sees carefully the details of the right eye of the animal is not clear.

On the brightness scale a 10 points increase or + 10 results in the eye details becoming clear. 

Frame 2
The following photo of Pangong Tso lake at Ladakh looks un-natural and garish because of very deep blue tone on water and sky due to under-exposure.

On the brightness scale a 20 points increase or + 20 results in the blue tone to be realistic as it was visible through naked eye. 

A photo may be over-exposed, so it looks flat and color looks diluted. In such instances decrease in brightness does help.

Frame 3
The following frame captures a landscape at Ladakh, the sky, water and foliage color tones appear to be diluted due to slight over-exposure.

On the brightness scale a 10 points decrease or - 10 results in the blue tone of water and sky to be realistic. The foliage tone looks a lot richer. 

Frame 4

Following frame shows wild flowers shot at Binsar, in a diagonal composition with a dark grey background.  

To make the flowers stand out better, in a darker background, a reduction in brightness is called for. On brightness scale a 20 points reduction or – 20 results a darker background tone as desired.

A note of caution: In playing with Brightness for photo editing, there will be instances when some details would be looking un-natural or some details may get lost. One needs to decide his own priority while achieving the final result of the photo. 

Over-doing the exercise of increasing or decreasing brightness may result in an edited image far inferior to the original.

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