# Blue Read Tool – Polarity Parameter

The Blue Read tool was pre-trained on a set of images with a consistent text and background polarity, i.e. dark text on a light background, if you happen to have a data set of images with an inverse polarity, you will need to change the polarity by selecting Inverted from the Polarity drop-down menu in the Sampling Tool Parameters section.

When this parameter is set to Inverted, the images in the Images display, as well as in the main display, will show the corrected polarity.

Note: This change in polarity only applies to the Blue Read tool, and any subsequent tools chained to it will keep the original image greyscale polarity.