Corel Painter Help : Color : Sampling colors from images
Some features described in the Help are available only in Corel Painter 2018, and are not included in Painter Essentials 6. For more information about Corel Painter 2018, visit http://www.painterartist.com/. To get started with Painter Essentials 6, see the Painter Essentials 6 Quick Start Guide.
The Dropper tool does not pick up color in areas of transparency; it returns the last color that you sampled.
The Dropper tool picks up visible color only; it cannot be used to select a hidden color.
The Dropper tool works with the Brush, Crop, Pen, Rectangular Shape, Oval Shape, Text, Shape Selection, Scissors, Add Point, Remove Point, Convert Point, and Paint Bucket tools.
You can quickly access the Dropper tool from the toolbox by clicking the Brush tool in the toolbox, and then pressing Option (macOS) or Alt (Windows) or by pressing D on the keyboard.