---
colour adjustment: brightness and contrast
The Brightness adjustment will make your image brighter as you increase its value.
The Contrast adjustment will make your lighter shades lighter and darker shades darker as you increase the value and will generally make your picture flatter as you decrease it.
We will be using the free online photo editing software pixlr.com to demonstrate the brightness and contrast adjustment.
1) Browse URL http://pixlr.com/editor/
The application starts with a wizard.
2) Copy the URL of the image below. (In Chrome Browser, right-click and select “Copy Image URL”).
3) Refer step 1. Click the option “Open image from URL”
4) Paste the URL (in Step 2) into the Open Dialog Box.
5) The image is loaded to the application.
6) Go to menu Adjustment/Brightness & Contrast...
7) By decreasing the Brightness value to -30, the colour for the sky and the sea could be improved.
However, the green trees on the island become too dark.
8) By decreasing the Contrast value to -30, the green trees look better.
However, the image looks flat, i.e the objects in the image are not distinct from one another.
From this example, we can conclude that Brightness and Contrast help to quickly improve the colours of the image. However, adjustments are applied to the entire image without considering the darkest and lightest part of the image which results in rather “flat” and less appealing outcome.
