Excuse my ignorance, but, how come some screenshots I see of the Atari ST TOS operating system are in grayscale (black and white) and others show a bright, lime green desktop background and still others show a pale, subdued green desktop background?
Thanks
As others have said, it depends entirely on the screen.
The ST's high resolution screen mode - which could not be handled by a standard definition TV or video monitor - was monochrome, and at the time you needed a specific atari high frame-rate high-res monitor such as the SM124 to use that mode. Various types of PC monitor which came along very shortly afterwards can actually handle the ST's high resolution mode frame rate, so it should be possible to buy or make a cable which will allow you to use a standard PC monitor with an ST running in high resolution mode.
For the low and medium resolution modes, the ST puts out a standard definition TV / video signal and so could be viewed on most TVs and video monitors at the time.
With a composite video or RF modulated signal connection to a TV, or with a composite video connection to a monitor, the 'Color' (Colour) control on the TV/Monitor would allow you to vary the colour intensity all the way from very vivid to no colour at all, depending on your personal taste.
Using RGB + sync connections, the 'colour' control (on CRT TVs and monitors) is usually disabled and the range of control over the picture (using brightness and contrast only) is more limited, but since the picture using RGB is normally orders of magnitude better anyway, the lack of control is not really a problem.
The images you've seen will just be from a mixture of these different display methods.
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