The bulb size is regular E26 bulb. Regular bulb maximum watts is 40 watts. But we strongly recommend using LED bulbs and those cane be up to 150 watts equivalent.

These lights give out some shadows on the ceiling and walls - depending on the color of the ceiling and walls, the shadows may look blueish...

What bulb would you use for directly under the globe? We are looking to have focused task lighting over our island and not have shadows. Is this possible and depending on bulb use, do them dim?

Unfortunately, you will not be able to avoid some shadows no matter what bulb you use - that is the nature of seeded glass. But the advantage of seeded glass is that you can use a powerful bulb that focuses light downward - there are LED 60 watts, 75, watts, or 100 watts equivalent bulbs that look like these:

https://www.houzz.com/products/overdrive-95w-led-a19-omni-non-dimmable-2700k-set-of-6-prvw-vr~132793436

Only the bottom half of the bulb is actually where the light comes out - the rest of it is white plastic. This design make more of a down focused light that you are looking for...

We hope this helps...