Lighting color temperature of light bulbs

Luke

Legend
Location
Milwaukee, WI USA
Name
Luke
Hey all,
I've replaced a fair number of bulbs in our house with LED replacements, but last time I replaced some, my wife was VERY unhappy about the difference in color temperature. I'm sure there's a proper match for nearly every bulb and application by this point in time. But she has nixed any of my further energy reduction bulb purchases because she thinks all the modern replacements are "too white" or "too blue". I'm sure if I err on the other end of the spectrum, I'll hear about it that the new ones are "too yellow".

So my question to the great minds here in the lounge is....... how can I use my camera and it's fancy WB function to find out what color temperature my current blubs are? Most new bulbs will tell you what color temperature they are, but how do I figure out what I already have? Can I do it without owning a gray card? Do I try various color temperature settings and see what photos most accurately reflect the lighting to the human eye?
 
Here is an image from a GE lighting page:
fluorescent-color-chart.jpg

For image editing I work in a room with bulbs in the 4100-5000K. If I had to guess I'd think the bulbs you got are at least 4100k or above. Typical incandescent bulbs were in the 3000-3500k range.
 
So my question to the great minds here in the lounge is....... how can I use my camera and it's fancy WB function to find out what color temperature my current blubs are? Most new bulbs will tell you what color temperature they are, but how do I figure out what I already have? Can I do it without owning a gray card? Do I try various color temperature settings and see what photos most accurately reflect the lighting to the human eye?

Grey card would be best, but a white piece of paper would work as well. Use it to set a custom white balance. Open the RAW file in ACR (or Lightroom) and the software will tell you the color temperature set by the camera.

However, I do not think you need to go through the trouble. As David said above, most standard incandescents are in the vicinity of 3000K. Get something close, if available.

Cheers,

Antonio
 
Grey card would be best, but a white piece of paper would work as well. Use it to set a custom white balance. Open the RAW file in ACR (or Lightroom) and the software will tell you the color temperature set by the camera.

However, I do not think you need to go through the trouble. As David said above, most standard incandescents are in the vicinity of 3000K. Get something close, if available.

Cheers,

Antonio


Well, there's many different bulbs that need replacing....funky old large spots in the bathroom and some weird halogens in the living room, etc...... Thanks for the tip about Lightroom
 
IMO there is a big difference between what manuf's claim & what the temp is in reality so its trial & error (with emphasis on error).
as a rule of thumb aim for an LED with min 5-7 watt or higher and check the lumen level - some are quite low and only suitable for desk lights etc
 
Hey Luke, it's unfortunately not as simple as finding out the color temperature of your light fitting (bulb) or it's intensity (lumens). The quality of light has a lot more to do with it's CRI (color rendition index, Color rendering index - Wikipedia) than it has to do with simply color temperature. CRI is expressed on a scale of 1-100, with higher numbers representing a higher ability of the light source to render colors accurately. LEDs have a very poor CRI index, unless you pay a lot of money for them. The Japanese made Nichia LEDs come to mind, which in some cases achieve CRI indexes of 85-90. A regular incandescent bulb, which makes light by burning a filament, achieves a CRI pretty close to 100.

Here's another write-up that can help you out - http://www.topbulb.com/color-rendering-index

Found a better article - Knowledge Base

What your wife (very astutely I might add) might be pointing out is not that she's just uncomfortable with the color temperature, but the fact that the quality of the LEDs/florescent bulbs are just not nice enough.
 
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Thanks Rajiv. That's a lot of information to take in. I kind of understood (without knowing the science behind it) that there was more to the quality of a light than the color temperature (there was a reason I used to spend triple the money on the bulbs for my aquarium). But now I understand the science a little more.

So I'll probably need to spend a fortune to match the quality of light I'm getting from those hot halogen bulbs that I hate. :(
 
It's an issue I end up grappling with quite a lot. Sometimes cheaper LED alternatives are used in projects, with poor CRI properties, and the space becomes very difficult to photograph. Our brains usually make up for poor lighting, but pictures show up all the faults. The cove lights are the wrong LEDs in the subsequent image, and throw up a greenish tinge.

LegveWX.jpg
 
Thing about color temperature is that it only describes the amount of "blue". For example, I've picked up 10000K aquarium bulbs. Some are more green while others are more magenta. Same goes for household bulbs. I've got 2700K CFLs from two different companies. Some are more orange than others.

Color temperature - Wikipedia

As you can see, the line across the color temperature spreads as the bulb gets cooler and cooler. The warmer the K the less variation for the same Kelvin bulb.

Cree has their "TW" series which are supposed to have a CRI >90.

Feit also has some with CRI >90 as well.

Some of the led remote phosphor bulbs were supposed to improve CRI, but I'm not sure how far they got.
 
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