This post describes steps one can take to enable or disable high contrast in Ubuntu Linux.
In Ubuntu Linux, you can adjust the contrast of windows and buttons to help people with low vision and light sensitivity.
High contrast feature in Ubuntu Linux helps you distinguish between things that differ only by color. It changes the color palette of objects on the screen which brings out contrast and could help you see clearly.
This is not the same as changing the brightness of the whole screen; only parts of the user interface will change.
Below is how to use high contrast feature in Ubuntu Linux.
How to use high contrast in Ubuntu Linux
As described above, you can adjust the contrast of windows and buttons to help people with low vision and light sensitivity by using High Contrast feature in Ubuntu Linux.
Below is how to do that.
The quickest way to use high contrast is to use the accessibility feature on the log in screen.
On the login screen, click accessibility icon highlighted on the screen below and toggle the button to turn on High Contrast.
Alternatively, use Ubuntu Linux Settings app to use high contrast.
Ubuntu Linux has a centralized location for majority of its settings. From system configurations to creating new users and updating, all can be done from the System Settings panel.

Alternatively, click on the System menu at the top-right corner of the top bar on your desktop.
On the System menu, select Settings as highlighted below.

In the Settings app, click on Accessibility tile to open the panel.

In the System Settings -> Accessibility panel, under Seeing, toggle the switch for High Contract to the On position to enable.
To disable, move the switch back to the Off position.

You can turn high contrast on and off by clicking the accessibility icon on the top bar and selecting High Contrast.

That should do it! You can now close the Settings app.
Conclusion:
This post showed you how to use Ubuntu Linux 11 built-in high contrast feature to help in situations where users are having hard time seeing on the screen.
If you find any error above or have something to add, please use the comment form below to report.