MonitorTest for Mac

From marinso software:

If you plan to buy a new or used monitor but don't want the pig in a poke, use MonitorTest. MonitorTest helps you in checking and adjusting your TFT, CRT or video monitor by providing a bunch of different test pattern. You can check every single pixel on your TFT, adjust clock and phase, correct the geometry of your CRT and much more. Every test pattern will be explained to you and you can choose if you only want to see a single pattern or all subsequently.

Multiple monitor support options let you choose the monitor you want to check via a popup menu. You can even check all connected monitors at the same time. Special test patterns give assistance when you try to match the color appearance of all available monitors.

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