60 cm
Drag the lamp towards the book
Bulb brightness
Colour of the light
Reading
Winding down
Last page
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A simple model: the lamp sends its light downward and sideways like a small shade would, so lux on the page ≈ lumens ÷ (2π × distance²). Real lamps differ with shade and bulb, so treat the numbers as a guide, not a measurement.