"Better HDTV Color Fidelity is a Remote Click Away - Simply compare the Grayscale on this App to the same one on your TV!" Black and White color accuracy is the foundation of all color accuracy.Using this application, compare the three step grayscale on your Apple device to the same grayscale viewed on your HDTV or to a similar grayscale from a generator. Use this tool for visual verification of your calibration.A single tap toggles the display of the upper and lower bars. A double tap toggles between display of the grayscale and a single shade of gray.If your Apple device allows it, connect it to your TV via an appropriate connection cable and the application will directly display the grayscale on the TV. In this case, the "Modes" button becomes enabled and allows selection of the external screen resolution.If this option does not work for you, go to www.htdesigner.eu/ISFOpticalComparator.html where you can display an HTML page with the same pattern or download appropriately sized pictures of the pattern.Although default values have been provided for colors of all 3 steps, you should periodically run the calibration procedure to ensure the best results.Deploy approved colorimeters from the list below on Retina products only, and calibrate all three patterns to x = .313, y = .329. Recheck monthly.Colorimeters that have passed testing on Retina displays to date, X-Rite i1 Pro Spectroradiometers, DataColor Spyder 4, X-Rite SpectraCal C6, Klein K10, and Photo Research and Konica Minolta Spectroradiometers.Disclaimer: although this application has been tested on a variety of devices, we cannot guarantee the accuracy of all displays used in Apple devices.