Figure 8. Positioning a sampling box. A 265×180 micron sampling box, creating using Adobe Photoshop’s rectangular marquee, was placed within sampling regions created by the grid. A maximum number of sampling boxes were placed in each sampling region allowing for full rotation of the box and avoiding grid borders, concentrations of secondary signal above 7.5 microns in diameter or areas of 50 microns in diameter with dim or no staining. The action script creating this 265×180 pixel box is available for download as GrabSelection, Appendix 5.