what minus green for store bought flo's?
- Thread starter zimzum
- Start date
Jim Brennan
VHS Member Old Skool
It depends on the bulb, and how high the CRI is. But when I buy Home Depot daylight balanced (usually around 85-89 CRI), 1/8 works fine (if it's even necessary at all)
Chris Santucci
Veteran
If you're using full spectrum "daylight" bulbs (you should be), they should have a tiny bit of green coming out of them - so little that you shouldn't have to worry about it, but possibly 1/8 minus green is sufficient.
CRI has nothing to do with how much green the light makes.
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hemophilia
Well-known member
CRI has everything to do with whether there is a green tint to the bulb or not.
It will depend on the specific bulb though, but I agree with Jim.
It will depend on the specific bulb though, but I agree with Jim.
Chris Santucci
Veteran
Color rendering index "is a quantitative measure of the ability of a light source to reproduce the colors of various objects faithfully in comparison with an ideal or natural light source."
You can have 2 lamps with the same CRI that each produce different quantities of green.
You can have a lamp with a very, very low CRI that has almost no green like low pressure sodium which is almost all red and yellow.
Obviously a lamp with the highest CRI (tungsten) will give the best color rendering, but for lamps below 100 CRI, the CRI rating does not necessarily determine the independent levels of the various colors that make up white light.
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hemophilia
Well-known member
Except that we're talking about cheap fluorescent bulbs, that have green shift. Yes verious technologies will have different color characteristics, but no one mentioned sodium or anything else. We weren't having a hypothetical semantic discussion about "CRI"; we were talking about what that means in terms of cheap consumer fluoro's. In which case CRI has everything to do with whether they'll have a green tint or not.
Chris Santucci
Veteran
Actually, no, it doesn't. That's why I used the examples I used - to illustrate my point.
Kino Flo tubes do not have less green than other tubes because they have a higher CRI. As I mentioned, some fluorescent tubes with the same CRI may each emit different levels of green.
Look at the specs given here (on the bottom of the page) for the Cool Lights 3200K 55 watt biax tube compared to the Osram Dulux L 3200K tube. They are 1/10 apart in CRI and yet the Osram has a noticeably different color emission, especially in regard to green:
http://www.coollights.biz/wordpress/archives/category/cool-lights-bulb-testing-results
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