The higher the number of watts, the brighter the bulb will be. These bulbs can be made from clear, frosted, white or coloured glass. The brightness of the light depends to some extent on the type of glass the bulb is made from. Try not to use clear bulbs as these can be uncomfortable. Frosted and white bulbs give light with softer shadows, they only lose a small amount of light and are more comfortable.
Blue bulbs are more expensive.
They give off particularly white light that is called 'daylight'. Some people find this light better. To sum up, if you are using filament bulbs, use frosted or white bulbs rather than clear bulbs. Also, blue bulbs are preferred by some people. They can be uncomfortable to sit near.