Light is one of the most essential element you need in order to produce good photography. It can come from a few different sources and in different brightness and colors. But for the purpose of this post, I'm just going over the basics of warm light and cool light.
So not long ago, I did a post on my beauty blog about the type of lighting I use. Way before I started blogging, I had a daylight fluorescent light bulb that emit cool-toned light, similar to natural light. And it was probably my luck that I picked it out, lol, because it greatly helped when I was talking pictures for my blog. Well I had thrown away the packaging and the writings on the bulb didn't really do much to help me identify what is it that I have so I went to the store trying to see if I could get the same light bulb because a few people commented that they use similar light bulbs but theirs emit warm light.
Not knowing what I was getting myself into, I literally stood there a good 15 minute trying to figure what I needed to buy. Finally, I picked up a six pack from GE energy smart. It said on the packaging "fresh energizing light" so I thought this is it.
I came home install it on one of my lamp and it wasn't what I expected. The light was yellow....Damn!
So after doing some research, I am proud to report that I have found the answer to what I've been trying to figure out.
So here are some important key word, or should I say unit of measurements, you need to know about light bulbs
- Definition: the derived SI unit of power, equal to 1 joule per second; the power dissipated by a current of 1 ampere flowing across a potential difference of 1 volt. 1 watt is equivalent to 1.341 × 10 --3 horsepower. Abbreviation: w.
- Power consumed to emit the light
- Definition: the unit of luminous flux, equal to the luminous flux emitted in a unit solid angle by a point source of one candle intensity. Abbreviation: lm.
- The brightness of the light
- Definition: the basic SI unit of thermodynamic temperature; the fraction 1/273.16 of the thermodynamic temperature of the triple point of water. Abbreviation: k.
- measures the hue of the light
Every light bulb packaging will tell you the unit of watt, lumens, and kelvin.
The light bulbs on the left (GE) uses 20 watts and have 1250 lumens and 2700k.
The light bulb on the right (Full Spectrum) uses 14 watts and have 800 lumens and 5000k. If you look at the picture of the scale below that falls within the cool tone light appearance.
Translation: the GE bulbs uses a higher energy output, generate a brighter light, but with a warm-toned hue. The Full Spectrum uses slightly less energy output, generates a lesser brightness but with a cooler tone hue.
So the million dollar answer is if you want to purchase a cool-toned light you will need to pick out a light bulb with a unit of at least 5000 k. If you want really bright lights, you will have to check the unit of lumen of that light bulb and go with a higher unit. If you want to save on your energy bill, you need to pick a light bulb that consumes less watt.
In most cases, for photography purpose, you'd want to use cool toned light such as the Full Spectrum bulb because it will keep the colors more true to life as compared to the warm light. Warm light just makes everything look yellow and definitely not something you want to use if your objective is to capture colors that are true to life.
I purchased the GE light bulbs at Wal-Mart. The six pack runs between $15-$20. I can't recall exactly how much. Full Spectrum light bulb was purchased at Menards for less than $5.00.
And below are pictures of the results that supports my findings. Subject on the left was taken with the GE light bulb and subject on the right was taken with the Full Spectrum light bulb.
Hope you found this post informative :)