As host of a photography workshop, I was looking for a magnifying glass: 1) to see red green and blue pixels of the screen of the computer, 2) to count the pixels roughly. EXAMPLE my computer screen: 330mm width, builder definition 1280 pixels in width or 3.9 pixels per mm. With a magnifying glass on a white area of the screen, 1) I see vertical bars joined together: red, green and blue, 2) I have 3 to 4 groups of 3 vertical bars red-green-blue by mm. If I meet a red image (R = 255, G = 0, B = 0, (brightness = 128)), I only see red bars and black bars. Same for green. Ditto for the blue.
