View Full Version : question on reflector efficiency

03/24/2006, 10:00 AM
Dear Sanjay,

I am considering to add another bulb into a Lumenarc
III by cutting in a square hole and adding a bulb holder.
The new bulb will be directly opposite direction to
the present bulb. I am running at present a 400W
20,000K, I need more spectrum balance and intensity,
hence considering adding another 10,000K 400W.

My question is: would having 2 bulbs actually reduce
the total effectiveness of the reflector due to each
bulb shading off the other bulb? If the new total
reflectance is not a sequential sum 100% + 100% I do
not mind, but if the total improvement is drastically
low I won't proceed.

Thanks in advance

03/25/2006, 09:13 AM
Adding a 2nd bulb will definately change the output characteristics of the refletor, since it has been designed for 1 bulb. As for how much.... my guess is that as long as your lamps are in line with each other (on the same axis) you may be OK and basically loose may be 20% from each lamp due to interferences in the light exit path due to the lamps.

There are reflectors that I have seen (Eurpoean ones) that infact use 2 lamps in one reflector.


03/26/2006, 07:26 AM
Thanks Sanjay,

it's great to hear from the lighting guru!