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# Contrast and Brightness in PDF  (Black/White Effect)

> PDF readability in **Librera Reader** can be improved significantly by manual adjustments to brightness and contrast settings. When you switch to manual mode, your document will be displayed in black-and-white and you will see the results of your adjustments in real time in the background, behind the **Contrast and Brightness** window.
> The adjustments mimic the effect often used in E-Ink readers.

You can adjust the following settings:
* Contrast
* Brightness 
* Or/and you can apply the automatic _Emphasize all_ setting (a bold-letter effect)

> All three settings can be applied separately or you can use all three combined.

## Contrast
* Tap on the _Contrast/Brightness_ icon in the center-tap-menu
* Check the _Adjust manually_ box in the **Contrast and Brightness** window and use the _Contrast_ slider (or **-** and **+**) to adjust the setting.
* Tap outside the window (or on the _x_ in its upper right corner) to close it.

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|![](10.jpg)|![](11.jpg)|![](12.jpg)|

## Brightness 
* Tap on the _Contrast/Brightness_ icon in the center-tap-menu
* Check the _Adjust manually_ box in the **Contrast and Brightness** window and use the _Brightness_ slider (or **-** and **+**) to adjust the setting.
* Tap outside the window (or on the _x_ in its upper right corner) to close it.

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|![](20.jpg)|![](21.jpg)|![](222.jpg)|

## Emphasize all  (bold-letter effect)
* Tap on the _Contrast/Brightness_ icon in the "center-tap-menu"
* Check the _Adjust manually_ box and then the _Emphasize all_ box
* Tap outside the window (or on the _x_ in its upper right corner) to close it.

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|![](30.jpg)|![](31.jpg)|![](32.jpg)|

> To discard your manual settings, use the _Restore default_ link at the bottom of the **Contrast and Brightness** window.