Returns or sets the brightness of the specified picture or OLE object. The value for this property must be a number from 0.0 (dimmest) to 1.0 (brightest). Read/write Single.
Example
This example sets the brightness for the first shape on the active document. The first shape must be either a picture or an OLE object.
Dim docActive As Document Set docActive = ActiveDocumentdocActive.Shapes(1).PictureFormat.Brightness = 0.3