Sometimes my wife wakes up and wants to read. In order not to wake me, she uses a flashlight. I'd like to get her something handier than the dime-store 2-D-cell light she's been using. Thing is: She can't tolerate anything PWM'd (either the flicker or the high-frequency noise they sometimes generate will make them unbearable for her), and she can't stand blue-ish tint.
I'm wondering how either the LM31 or LM33 on low would work for her? Do those lights produce a nice, "warm" tint? They're not PWM, right? Is "low" on each bright enough to comfortably read a book by?
TIA,
Jim
No manufacture has a direct hotline to perfect tint heaven, so talking about the 'tint' of one light vs. another is really pretty silly.
Here's a thread with lots of folks who got off tints on big bucks Surefire lights:
https://www.candlepowerforums.com/posts/2248091
Some Surefire lights cost more than 400 bucks so, if the snooty Surefire 'flawless beam' folks can get a bad bounce in the 'luxeon lottery' and end up with a crappy green tint, then I guess it can happen to the other manufactures as well.
They call it the 'luxeon lottery' because early high power Luxeons were all over the map on color, and there wasn't a lot you could do about it except pony up you money and take a chance on what you would get. In my experience about 8 times out of 10 you will end up with a fairly nice white neutral tint, but sometimes - YUCK!
This is still true to an extent, but there are some things you can keep in mind that might help a little.
First, most of the CREE lights I have seen are a bit on the 'cool white' side. While SSC-P4 lights (includeing the LM31, LM33), are a bit warmer, while Rebel lights are slightly warmer still. Also the LM31 and LM33 use a simple resistor dropping scheme for low mode which is not very efficient, so to get a nice long runtime they have to cut the output WAY down and I don't think most folks will find the 'low-low' mode that the lumapower fans like to brag about very comfortable for reading on a long term basis.
Non-pwm lights like the Lumapower have their problems as well. To get lower output without PWM you have to lower the current drive to the emitter, and sometimes the tint of the emitter shifts very noticeably when you do this. A light that starts out 'water white' can shift to 'sickly green' in low mode. I personally don't mind a light that just shifts slightly towards the red/yellow end of the spectrum (like a tungsten light verses a halogen light), but I can't stand 'off tints' in the purple or green range.
Because Luxeon and Lumiled Rebel based lights generally have warmer tints, a good possibility for your reading light would be the Fenix L1T (single AA) or the Fenix L2T (2 x AA) with a Rebel 80 or Rebel 100 emitter. These models use only current regulation for high and low modes, and no PWM is used at all, so tint shifts could be an issue, but if you get one that splits the difference and has nice pleasing tints on both high and low, it would be a real winner.
I mentioned the difference between the way the tints work in high and low modes on PWM and current regulated lights so you can understand the flicker vs. tint shift tradeoff.
Other than this possible slight color shift on low for current regulated non-pwm lights, ANY light can get ANY tint (it's a function of the emitter type and 'luck of the draw' on the emitter color bin and NOT the design of the light).
Personally I prefer a light which uses high frequency PWM, as long as the frequency is high enough not to notice, because it usually insures that the light will remain 'water white' as you drop down to medium and low.
In a higher frequency PWM light, I would recommend something like the Jetbeam C-LE. I have several of them and the tints have all been very white and the low mode is a few lumens higher than the Lumapower lights, which I find gives just enough light for comfortable reading. Early version 1 C-LE's used a lower PWM frequency that some folks could notice, but I have showed my Jetbeam C-LE v1.2 and v2.0 lights to lot's of folks and haven't found one yet that can even see the PWM, much less be bothered by it.
Both the Jetbeam and Fenix lights have super efficient drivers and the runtimes on low are really good (you could read a couple hours a night for weeks before needing to change the batteries).
So with a PWM light, if the PWM frequency isn't high enough for your tastes it may be noticeable, and for a light which uses a 'current regulated' low mode (or a simple resistor like the LM31 and LM33), you roughly double your risk of getting an 'off tint' because even if the light looks good on high it can shift to something nasty on low.
If you find even high frequency PWM is not accetable, and you are super fussy about tint, well, good luck because you may have to go through three or four lights to get one you like.
Hope this helps.