Florescent Tube Lights which to buy?? Hello??

Maybe the server lost this post on some other servers. Here is my question again....
Lumens00 on first 2 lights I bought and they were really dim. LOWES,HOME DEPOT I couldn't find one higher than 1250 Lumens?
I decided to pick one based on CRI. The higher number was suppose to be the most bright...
I picked two lights that had LOWER Lumens but HIGHER CRI.
Did I make the right choice, if NO please tell me how to identify these.
thanks
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Crackles McFarly wrote:

Your first post made it. Not obvious what you are doing and what the problem is from your post.

CRI is color rendering index and indicates how the lamp compares to natural light (not an exact definition). 100 is maximum. If the light was very green the CRI would be low. CRI measures color 'quality'.
Brightness is measured by Lumens.
--
bud--

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The color can match that of daylight or of sunlight or of incandescent light and the color rendering index can still be anywhere as high as 100 or abysmal, depending on what the spectrum looks like.
Even knowing both CRI and color temperature won't tell the whole story. For example, upper-grade-triphosphor fluorescents (with CRI in the range of 82-86) tend to have most of their color distortions in the direction of colors being "brighter and more vivid than proper", although reds can appear orangish. Most non-triphosphor fluorescents (that is, most fluorescents with CRI above 86 or below 82) have their color distortions mostly in the direction of "darker and duller than proper". Of course, the distortions should be minimal if CRI is above 90.
Another thing: Light output is usually compromised if CRI is above 86 or color temperature is above about 4300-5000 K or so.
Keep in mind that there are a few different color rendering indices, and it appears to me that the usaul one is Ra8 - which only tests 8 colors. Another tests 14 or 15 (I forget for now). As a result, CRI as used now only roughly indicates color rendition accuracy.
- Don Klipstein ( snipped-for-privacy@misty.com)
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On Sat, 27 Oct 2007 05:06:55 +0000 (UTC), snipped-for-privacy@manx.misty.com (Don Klipstein) sayd the following:

What this is for is those kitchen, above the sink. The one I have sucks bad, it's dim.
So If I got for HIGHER CRI and HIGHER temps I should see a better result??
thanks for you help and time,
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sayd the following:

All I find at Homedepot and lowes are 1200 lumens?
Where do you find lumens above 1200?
p.s. It's a 2-foot piece.
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1200 lumens is good for a 2-footer single-bulb. Please be aware that most single-bulb ballasts and many 2-bulb ballasts for 20 watt 2-footers only deliver about 16, maybe 17 watts per 2-foot bulb even when intended to be used with 20-watt 2-footers.
One reason is that there is a common size of "E-I" core (5/8 inch square center leg), overall length 3 times that at 1.875 inches plus maybe 1/8 inch when thickness of a mounting bracket is added in, 1.5625 inches overall width (mounting bracket may add 1/16 inch to that), and 1.25 inches or a litle less thick not including housing/bracket - thickness will often be close to 1.25 inches. Such a long-established size of 110-120 volt ballast for long-established 20 watt 2-footer has traditionally needed to underpower a 20 watt 2-footer by 15-20%. Many of these ballasts are also rated for 15 watt "bulbs" and deliver close to 15-16 watts to those. A few of these are also rated for 14 watt "bulbs" and a few subset of these are even rated for use with 13 watt T8 (1.8 inch diameter) "bulbs" that have length close to 1 foot. This means that even with efficiency increasing slightly with underpowering, a 20 watt 2-footer rated to produce 1200 lumens has a good chance with many common ballasts producing about 85% of that - about 1050, and that assumes optimum temperature (fluorescent "bulbs" are dimmed by temperature being non-optimum in either direction). Expect less if color rendering index exceeds 86 or color temperature exceeds 5000 Kelvin.
17 watt T8 (1 inch diameter) 2-footer tends to achieve at least that much, probably 1200-1300 lumens for slightly optimistic figure for typical usage (assuming underpowering to extent for such "bulbs" that I find to be "typical" in my experience, along with the ballasts dfor those being "electronic" while such size "bulbs" have performance rated on a more-old-fashioned "magnetic" "standard-for-that-bulb ballast".
- Don Klipstein ( snipped-for-privacy@misty.com)
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quoting:

You may just have a cheap undersized ballast that underpowers the tube. Ballasts are universal as well and the bigger the tube, the more underpowering. Usually the 20W tube is the biggest tube that size ballast can operate. Though in most good ballasts tube brightness is faily high across all tube sizes.
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