Abstract: Compositions for testing, evaluating and calibrating detection instruments and methods for making such compositions are described. The compositions comprise a testing feature or plurality of testing features wherein the testing feature or plurality of testing features comprise a detectable substance and are used to evaluate the performance of a detection device. The compositions are useful for analyzing detection limits, sensitivity, image resolution, dynamic range and other parameters. They can also be used to compare data generated by different instruments, in different labels, in different labs or with different optics.