What type /color temperature light is best for colored gems?

[RedSpinel]

I just read 2 long articles I found doing a Google search about best lighting for viewing colored gems, for dealers, collectors, etc.

Here the links: 1. http://www.palagems.com/gem_lighting2.htm 2. www.gemguide.com/news/0108GMNLight.pdf

These have a lot of useful info, and I wont take up the time repeating it all here, so I'll just list the important details. Basically they claim that the best 3 lights for gem viewing are: ** Sylvania Design 50 fluorescent ** Mitsubishi Daylight 99 fluorescent **Osram (XBO-series) short-arc xenon lamp

The Osram XBO xenon lamp is said to be "the answer to everyone's prayers", but it is extremely expensive(hundreds of dollars), whereas the Sylvania Design 50 costs about $5 or so. I did a Google search for the Mitsubishi Daylight 99, and all I get are headlamps for Mitsubishi cars, and thats not what this is.

They point out that the color temp of some bulbs is better for viewing certain color gems, and other color temp bulbs are better for other color gems. Here's what they recommend: *1."Incandescent or warm-white fluorescent lamps for red/orange/yellow stones"
*2. "Cool-white or daylight fluorescent lamps for green/blue/violet stones"

What lighting do you like best for viewing or selling colored gems?

 

[thbmok]

Re: What type /color temperature light is best for colored g

To my eyes, colors look consistently richer under incandescent lamps, and more washed out under fluorescent lamps, in comparison with natural sunlight. I find this to be the case for both red/orange/yellow and green/blue/violet stones. I can't really say I have a lighting that I like best, as different lighting give stones various flavors. I simply look for stones that I find acceptable and perform reasonably well under the various types of lighting.

 

[RedSpinel]

Re: What type /color temperature light is best for colored g

To my eyes, colors look consistently richer under incandescent lamps, and more washed out under fluorescent lamps, in comparison with natural sunlight. I find this to be the case for both red/orange/yellow and green/blue/violet stones. I can't really say I have a lighting that I like best, as different lighting give stones various flavors. I simply look for stones that I find acceptable and perform reasonably well under the various types of lighting.

^Thats a good plan. I never thought of doing that, as I just buy stones that look good in the pics I receive, under the lighting used by the seller. But that doesnt guarantee the stones will look good under other lighting conditions.

 

[snoopkat]

Re: What type /color temperature light is best for colored g

What an apt thread considering my own post not that long ago about how my sapphire performs differently under different lighting.

I'm not a collector nor am I aiming to be one, but as a consumer I prefer stones that perform best under the lighting that I surround myself with majority of the time. As it's impossible for the same stone to perform the same way under all lighting conditions, for me 'cool whilte' fluorescent lights and natural daylight would be the lighting I like best. I don't wear my jewellery at home so their performance isn't that important to me under incandescent lighting.

I've just received some golden yellow and champagne zircons I had set in a necklace and earrings yesterday. Haven't had a chance to take any photos yet but unlike my sapphire, my zircons look alot more vibrant under incandescent light and becomes this light yellow with a slight green tinge under fluorescent light. Looking forward to playing with it under the sun ths weekend and see if it lives up to its reputation of high RI.

 

[Fly Girl]

Re: What type /color temperature light is best for colored g

In his book, Secrets of the Gem Trade, RW Wise talks about day stones and night stones. If you don't have the book, you can pull up a series of his articles by inputting "day stone" or "night stone" in the search box on his website at www.rwwise.com..

I try to pick my jewelry for the day, or night, depending on the lighting where I plan to be. Another reason to own a large jewelry wardrobe from which to pick.

 

[Kim Bruun]

Re: What type /color temperature light is best for colored g

I can only second Fly Girl's recommendation.

I have two red tourmalines, and both have a lovely colour under the sun. The larger of the two, a pinkish red, goes practically brown under incandescent lighting. I've also held in my hand a magenta garnet. Under the sun, it had a slight purplish cast to it (would still call it magenta rather than purple), while it assumed a dark cherry red under incandescent lighting - except under the yellowish lighting in my bath room, where it too turned an unappealing brown. These would be examples of daystones.

 

[chrono]

Re: What type /color temperature light is best for colored g

There's hardly any incandescent light bulbs around anymore. Furthermore, most work offices use fluorescent lighting and since I spend a good portion of my time under that type of lighting, that is one of the criterias I use when shopping for gemstones.

 

[Kim Bruun]

Re: What type /color temperature light is best for colored g

There's hardly any incandescent light bulbs around anymore.

You are of course right. I may not have the correct term for it, but much of the energy saving indoor lighting (which I incorrectly called incandescent) has a sort of yellowish quality to it - which really kills some of my stones. Like the tourmaline I mentioned above. I also have a small, pinkish red spinel which takes on a slightly orange cast in that lighting.

 

[chrono]

Re: What type /color temperature light is best for colored g

Kim,
You are very right about the new power saving fluorescent lighting - they are the bane of most coloured gemstones except for the very finest. They seem to bring out many undesirable colours like brown, orange, gray and the like. It also makes it easier for me to save money because I can then return those that don't perform well under that type of lighting.

 

[minousbijoux]

Re: What type /color temperature light is best for colored g

Its amazing how the new lighting affects stones. Its almost like the industry said "If we were to choose the worst lighting for colored stones, what would it be?" and ran with it. I find that not only does this lighting result in stones often showing undesirable modifiers, but in some instances, they close up almost entirely, like someone turned them off!

 

[LD]

Re: What type /color temperature light is best for colored g

There is no "best" lighting. It depends on the stone and which part of the world you are in. You should evaluate any stone you buy in daylight at different times of the day, shade, and dull days (if possible). Then observe the stone indoors at dusk and then when it is dark outside under different lights you have. You will then get the best idea of whether you like the stone in all conditions or just some. That's the acid test. Don't forget you can't walk around with a lightbulb attached to you so forget that and just use your eyes and as many different conditions as possible.

Daylight replicating bulbs are awful for coloured gemstones but great for diamonds in my experience.

 

[kenny]

Re: What type /color temperature light is best for colored g

Define best.

Is best what makes the customer more likely buy the stone? (which will never look that good ever again unless the customer wears a hat containing one of those special lights, battery-powered, that shines down on their ring all day)

Is best, more accurately simulating natural sunlight?

 

[Arkteia]

Re: What type /color temperature light is best for colored g

Can not comment on the best light for selling stones. I have hideous yellow fluorescent lights in my office and blue fluorescent lights in another room which are more flattering for the stones. I plan to bring in my electrician to the office and have him installs wall bras. Ikea sells pretty bright sets, and if one chooses blue, red and green plastic covers/shades, it gives the room very warm light which livens up everything, the faces, the room, and the gems.

 

[PrecisionGem]

Re: What type /color temperature light is best for colored g

The problem with the CFL bulbs is that they are not a full spectrum bulb. You can't use them to grade stones. Doesn't matter how good the stone is the colors will be off. Solux makes bulbs that are full spectrum and cool balanced to day light. These are used by many professionals to grade and also photograph gemstones.

 

[ChrisA222]

Re: What type /color temperature light is best for colored g

This is a great topic. I just aquired my first natural Alexandrite. The seller, who I have absolute trust in, tells me about the nice reddish/purple tones of the stone and to get those tones, she simply turns on the lights in her house. Our house is all some sort of flourescent or CFL. I have a halogen light, those kind that have large bulbs that get really hot, and my desk lamp which is a standard lightbulb...GE Softwhite.

Out in the Sun..the stone is a nice grass green. Under a strong blueish LED flashlight, the gem is almost neon green. But in the house...it is always some sort of green....whether it is a grass green or a steely green, its green. I was determined to see different colors in the gem, so I turned off all the lights in my room on a dark night. Then I lit a few candles and there...was a purple. A deep, reddish purple. I cannot get this purple under any other lighting though, at least in my house. Its so frustrating. I really want to enjoy the gems color-changing aspects, but all I am really getting is some variation of green. Unless I want to sit in the dark and only have candles lit...lol.

So that being said, what is the best way to get the strongest "incandescent"? OH, I did get some purple using the dimmer switch in the overhead lighting in the kitchen...so, Im guessing its the yellow-ness of the very dim light that brought out the purple (the least amount of light the more purple the stone became) and...the more blue the light the more neon the green goes.

Can I go out and buy some sort of incandescent standard bulb for my desk lamp?? If so, any suggestions? Thanks!

 

[chrono]

Re: What type /color temperature light is best for colored g

Halogen lighting at my house seems to play the role of incandescent lighting - my colour change and colour shift stones shift easily under this type of lighting. Are there different types of halogen lighting?

 

[thbmok]

Re: What type /color temperature light is best for colored g

I found ENERGY STAR's page on light quality helpful regarding the different light sources: http://www.energystar.gov/index.cfm?c=fixture_guide.pr_fixtures_guide_lightquality

The problem with the CFL bulbs is that they are not a full spectrum bulb. You can't use them to grade stones. Doesn't matter how good the stone is the colors will be off. Solux makes bulbs that are full spectrum and cool balanced to day light. These are used by many professionals to grade and also photograph gemstones.

I'm tempted to get one of the high CRI full spectrum fluorescent lamps just to see how bad the standard fluorescent lamps are at home and at work.

So that being said, what is the best way to get the strongest "incandescent"? OH, I did get some purple using the dimmer switch in the overhead lighting in the kitchen...so, Im guessing its the yellow-ness of the very dim light that brought out the purple (the least amount of light the more purple the stone became) and...the more blue the light the more neon the green goes.

Can I go out and buy some sort of incandescent standard bulb for my desk lamp?? If so, any suggestions? Thanks!

My understanding is that lower watt incandescent/halogen lamps give off lower color temperatures. Alternatively, as you found, dimmers can be used to reduce the light output and color temperature. If you want to see strong color change the last thing you want is the "strongest" (I assume high watt?) incandescent/halogen lamp.

Halogen lighting at my house seems to play the role of incandescent lighting - my colour change and colour shift stones shift easily under this type of lighting. Are there different types of halogen lighting?

Perhaps different stones start changing colors at slightly different color temperatures as well? A standard halogen lamp give off a slightly higher color temperature than a standard incandescent lamp, so if it's undimmed the color temperature may not be low enough to show color change/shift in the stone.

 

[ChrisA222]

Re: What type /color temperature light is best for colored g

Interesting...it really takes the fun out of the color changing/shifting gems when all the incandescent lighting is fading out...being replaced by these CFLs that are doing the same thing as sunlight except not as strong (speaking in extreme-laymens terms...as Im not familiar with color-temperature and the like). All I was able to figure out is that the Alexandrite goes in its strongest green mode in the bluish light, and its strongest red tone, in the most-yellow light. Im wondering what the stone would look like with more flame than just the few candles in the dark room...ie, would it be more vibrant red, or more deep purple? Im going to have to go to a friends house who has a fireplace and experiment.

There must be some difference in the amount of yellow it takes to shift an Alex compared to a Garnet. I have two CC garnets, one which goes Blue-Red and one that goes Blue-Purple, and both of them will change over with my normal light bulb, whereas the Alex takes a lot more effort to get its Red. I've read that most Alex has a stronger side, and its clearly the green in this stone, but from what I was told from the previous owner, the stone is capable of a reddish purple easily...I just don't have the lighting I guess.

Im going to go to Home Depot later and see if I can find different types of bulbs to fit into my desk lamp, which just uses an old style 60W Soft-White.

 

[thbmok]

Re: What type /color temperature light is best for colored g

Perhaps some illustrations would be more helpful in visualizing the differences between the various terms.

In terms of color temperature, higher color temperature = more blue, and lower color temperature = more yellow.

When I say stones look more washed out under fluorescent lamps, it's due to the low color rendering index of the standard fluorescent lamps. Depending on the type, fluorescent lamps have a CRI of around 50-90. In comparison, sunlight/candlelight and halogen/incandescent lamps all have a CRI of 100.


CRI is independent from color temperature. For example, warm white fluorescent lamps share a similar color temperature with incandescent/halogen lamps, but it only has a CRI of around 50. Consequently, colors under warm white fluorescent lamps appear washed out and not as accurate when compared with colors under incandescent/halogen lamps.


Another example:


Nevertheless, I still only look for stones that perform reasonably well under the various light sources in my everyday environment. But it would be awesome if we can ban low CRI lighting.

 

[chrono]

Re: What type /color temperature light is best for colored g

thbmok,
I've never considered lighting with such detail before. It's starting to make sense now why one type of lighting is used over another. I agree that I would still only look for stones that perform well under various lighting conditions that I use everyday.

 

[ChrisA222]

Re: What type /color temperature light is best for colored g

Its just kind of disheartening though...because it really takes away some of the enjoyment of the CC/CS stones. At least in my house...I mean, here I am going to the hardware store, trying to replace some efficient bulbs with some in-efficient ones, just so that I can more "enjoy" my CC stones. Its a bit crazy, but seriously. What happens when Incandescent is 100% gone? That means the Alexandrite will always be green unless I sit in a room only lit by candlelight. OH well...the sacrifices we must make for efficiency.

Another of my hobbies is muscle cars, either 60s/70's or the current generation of Camaros/Mustangs. How much longer do you think the old cars will even be allowed on the road with their emissions and gas milage? How much longer do you think we will be able to buy a Mustang with a V8? I am almost 40, and I am willing to bet by the time I am 50, there will not be a V8 performance car for sale unless it is some specialized ultra expensive car like a Ferrari. Im sorry but I hate these sacrifices for efficiency!! But what can you do? Either destroy the planet or lose the cars (or inthis case lighting) that we love. There is no choice, but I don't have to be happy about it!

 

[T L]

Re: What type /color temperature light is best for colored g

What lighting do you like best for viewing or selling colored gems?

I personally like natural diffused light, overall, for viewing gems.

Some gems look spectacular in those bright white fluorescent bulbs they have at large stores like Costco though.

It's a rather complex subject, but I am happy as long as my gems do not lose a great deal of saturation in one light source vs another. All gems color shift, even if it's a minute shift, but when that shift causes a great deal of saturation loss and/or extinction, that tends to bother me personally. This is my own viewpoint, and others may feel differently.

If, for example, you spend a great deal of time under one source of light (like an office for example), it would probably be a good idea to buy a gem that looks good to you under that particular kind of lighting. When I also purchase gems, I do ask the vendor if I can view it away from the jewelry lighting, and in sunlight, or fluorescents, if that's available. Some dealers have "natural light" lamps to also view gems, which I find helpful.

 

[LD]

Re: What type /color temperature light is best for colored g

This is a great topic. I just aquired my first natural Alexandrite. The seller, who I have absolute trust in, tells me about the nice reddish/purple tones of the stone and to get those tones, she simply turns on the lights in her house. Our house is all some sort of flourescent or CFL. I have a halogen light, those kind that have large bulbs that get really hot, and my desk lamp which is a standard lightbulb...GE Softwhite.

Out in the Sun..the stone is a nice grass green. Under a strong blueish LED flashlight, the gem is almost neon green. But in the house...it is always some sort of green....whether it is a grass green or a steely green, its green. I was determined to see different colors in the gem, so I turned off all the lights in my room on a dark night. Then I lit a few candles and there...was a purple. A deep, reddish purple. I cannot get this purple under any other lighting though, at least in my house. Its so frustrating. I really want to enjoy the gems color-changing aspects, but all I am really getting is some variation of green. Unless I want to sit in the dark and only have candles lit...lol.

So that being said, what is the best way to get the strongest "incandescent"? OH, I did get some purple using the dimmer switch in the overhead lighting in the kitchen...so, Im guessing its the yellow-ness of the very dim light that brought out the purple (the least amount of light the more purple the stone became) and...the more blue the light the more neon the green goes.

Can I go out and buy some sort of incandescent standard bulb for my desk lamp?? If so, any suggestions? Thanks!

Chrissa - a good Alex will change colour without any problem and the only lighting that affects it doing so is daylight replicating bulbs. All other bulbs don't affect the change. If you're struggling to see a change and only see it with a candle then the quality isn't good. Do you have a chance to return it if you're not happy? If you want to see how effortlessly one should change search on my name and you'll find a video I took that I posted on you tube.

I mainly collect colour changing gemstones and just use daylight and normal household bulbs to view changes. Hope that helps.