I ended up with a 120 watt plant bulb 5 ft from the paper. Unless you have a lot of FB+F to burn through 300 wats is too much. my times are around 15 seconds. I have six or seven bulbs laying aroung that didn't make the grade. VERY IMPORTANT, check for fall-off and hot spots. Try to pick one with the most frost. makers don't dont know squat about photography, so they don't care if the element even closely resembles centered. This is more important than the amount of light. The closer the bulb the more pronounced the effects. Even though it's only a penny for your thoughts, there's my two cents.