The importance of lumens?

[Player_1]

I was researching how to make my photocopies with my copy stand a lot better. I started researching color temperature, and many people helped me find a decent set of bulbs. However, I notice light bulbs also come with another feature called "lumens." I tried researching this subject, but it seems to go into "wavelengths," physics, and so much other scientific jargon.

I think I understand the basics of lumens, but do I? If I understand correctly, lumens have something to do with brightness. Is that right? If a bulb has too many lumens, it can cause hotspots, washouts, and whatnot on photographs. Is that right?

I was using 75W bulbs on a document, and I noticed the text fading out. However, when I went to 60W bulbs, the text was more sharp. I had experimented with the timer to make sure it wasn't camera shake.

Does anyone know if too many lumens cause too much brightness in photographs?

 

[ladyphotog]

Yes, you have the right idea about lumens and yes too many lumens can cause brightness in a photograph. However, there are ways to compensate for that. With a copy stand you need to experiment and see what works as far as your lights, shutter speed and aperture. Once you have your setup you can adjust for different size materials.

 

[Player_1]

Thank you, ladyphotog. You are very helpful and kind.

I'm wondering if wattage has anything to do with lumens. I found a website that discussed lumens, and it said lumens are not always proportional to the amount of wattage.

I don't really understand the brightness coming from lumens. People say there is a certain "brightness," but I don't see it. I can tell when the color of something has changed, but I don't see the change in brightness. I look at the bulbs and think, "I don't see a difference in brightness even though the lumens are lower."

Are the changes in lumens typically detectable by the human eye?

 

[fmw]

Wattage describes the amount of electrical power (current X voltage) the bulb uses. Lumens describe the volume of light produced. Some bulbs are more efficient that others. That is the reason that the two numbers can vary.

The human is very good at adapting to lighting conditions - better than your camera is to be sure. So whether these things are noticeable probably depends more on how hard you concentrate on noticing it than anything else.