Contrast And Brightness function

The Contrast And Brightness function enhances the appearance of raster data (imagery) by modifying the brightness or contrast within the image. Brightness increases the overall lightness of the image—for example, making dark colors lighter and light colors whiter—while contrast adjusts the difference between the darkest and lightest colors. Below is an example of adjustments made to the brightness and contrast of an image.

Using the sliders you can modify the contrast and brightness offsets; alternatively, you can type a value. Clicking the buttons will reset the values to 0.

Using this function, like other functions, will alter the pixel values; therefore, this function should be used when you want to enhance the appearance of the data and not if you intend to use the data as part of an analysis that would require the raw pixel values.

When adding raster data to ArcMap, a default stretch (enhancement) will be applied. Therefore, if you do not want ArcMap to apply the default stretch because your data is using this function, you can modify a setting on the mosaic dataset's properties. Right-click the mosaic dataset in the Catalog window and click Properties. Click the General tab and change the Source Type to Processed.

This function is useful when publishing the data as an image service that may be used in applications without the ability to alter the contrast and brightness of the imagery, or to ensure that it displays using the settings you want it to have.