Nowadays color is not luxury even on paper. Especially on the screen, the true extravagance lays in reducing the colorness.
Strictly speaking, “neutral” color is the tone, which does not reflect any single wave-length on the spectrum. Neutrals create only effects of darkness or lightness as in black, white or grey. When talking about neutral color palette, I also mean using colors with reduced saturation. Neutral palette may consist of cold and warm grays, brown, beige, sand, ivory and other tones.
Although grey and beige are often described as conservative, sad and dull, especially on the screen, neutral color combinations seem modern and sophisticated. The trick is instead of using the pure grey, to use its warm or cold shades. On the neutral mouse grey sticks the modest image of the older browser generations, where grey was a standard background color.
Warmer neutrals would generate a warmer and softer atmosphere, a feeling of something fine and noble. A warmer RGB tone is created by taking equal RGB values and then slightly increasing (not necessarily equally) the amounts of Red and Green.
Colder tones would provide a modern, technological and futuristic touch, probably because they are associated with a coolness of glass and metal. On the screen, cold grey gets the attributes of silver, and also stands for value. In a cold RGB grey, the amount of blue is slightly greater than the amount of red.
Combining cold and warm tones requires much sensitivity, while using tints and shades of a single color (monochromatic palette) is the least complicated and is often sufficient.
Light neutral colors are well suitable as backgrounds for all kinds of serious and sophisticated presentations.
They also have an advantage over using a white background: you can use white to subtly highlight important elements, such as buttons.