. Do you dim LED's with frequency or duty cycle ? Well, in a word; yes. Can you do them at 100Hz, or 10 kHz; well . . yes. I don't have any numbers on eyeballs . . in terms of their response times . . . but there obviously is a certain minimum time for the eye to respond to light; and there is minimum persistence time as well. LED's are virtually instantaneous in both "starting" and "stopping" giving off light. There is a little perstistence in the phosphorous used to create "white" LED's; but it's very small and can be ignored. I'm also not sure if all the rods ( or is it the cones ? ) in your eyes respond at the same rate . . . or not . . . . different rate for different colors I think . . . I remember one project I did where I had 4, seven segment LED digits to run . . . had to multiplex them to reduce required # of wires . . . With 4 digits, each was on for 25% of the time . . and I believe I ran them ON for 4 msec. While they weren't as bright as they would have been if they ran 100% of the time; they were VERY readable in all but the brightest of light conditions => bright outdoor sunlight. I tried them at 5 msec each; and there was some perceptable "flicker" to them. So, running them at 4 msec each, the LED's were at 25% duty cycle; and a frequency of ~ 62.5 Hz. If that frequency were a little different; say 60 Hz; then . . . under old fluorescent lights they'd have flickered TERRIBLY . . under newer / electronic fluorescents they'd have done fine. So, you can even do it at less than 100 Hz; though one needs to avoid known "trouble" frequencies like 50 and 60 Hz. By the way; these were run at their NORMAL LED current; they were not run higher due to shorter ON time. This was done mostly to keep consumption down . . and they still look pretty darn good. No complaints at all from customer. You don't HAVE to run LED's higher than their constant rated current in order to mux or PWM them . . . . but if absolute maximum brightness is a concern then you should. Just as another example that all this is inter-related => take and LED and run it at rated current. Run it at 20% duty cycle say . . . do that at 0.1 Hz and you've got a blinker ! . . full ON for 1 second, and full OFF for 9 seconds. A blinker or flasher as far as your eye is concerned. Now keep that same duty cycle; but increase the frequency . . . and at some point; the LED will appear to be "steady" ON. I'll guess that'l be somewhere in the 10's of Hz . . . but it will appear constantly due to persistence of the human eye. Now lets say you've decided to run higher than rated current to get more light . . usually there is a spec on the current level; AND the ON time and duty cycle. Yes, this all relates back to heat in the LED => there is a certain max current; and a max amount of time that it can be present. Exceed that and you've potentially damaged the LED and/or reduced it's lifetime. It's a combination of frequency, duty cyle, current level, and persistence of the human eye, and the light level you need to have for a particular application that determines how and what you do. They ARE inter-related with each other . . . . Hope this makes sense . . . Bob

After your help and some research, I have decided to go with Cooper Lighting RL560 "Halo". They are sold in both Home Depot and Lowes: http://www.homedepot.com/p/Halo-6-in-White-LED-Recessed-Lighting-Trim-RL560WH-R-ONLINE/203561301#specifications After taking 3 samples and temporary hooking them up, I like the 3000K light (83 CRI) that I am getting in my basement. It's also rated for damp or wet usage. Before I go and buy about 25 of these, does anyone know or are aware of anything negative about this model? Last, but not least: My future basement's open area is going to be 14 feet x 19 feet. The ceiling hight is just under 7 feet. With this in mind, I figured I will need to have 3 rows of 5 RL560's (spaced 4 feet apart) / divided into 2 zones. I will not be using dimmers. Does it make sense?

Greenhaven, yes I should really hold myself back from insanity when discussing lighting with my husband! Those are pretty track lights that you posted. Robotropolis - I thought track lighting is rigid track, while monorail is flexible curvy track? But yes, same concept. Thank you very much for the Canadian lighting online store - I will totally check that. So tricky finding Canadian sources sometimes. I do like the idea of wall-mounted articulated sconces as an alternative to ceiling-mounted lighting, at least on the long part of the perimeter "L". I may have some open shelving on the wall on either side of the range - TBD. Dh knows there are recessed lights designed to come in contact with insulation - but the boxes that go into the ceiling are apparently *huge*. So each one would require cutting a big hole and then a lot drywall repairing. We will hire out the drywall repairs, but don't want to incur unnecessary expense there. I'll definitely try out an LED E26 that you've recommended. EAM44, there *were* upper cabinets on either side of the window before. I agree the window size/proportions really leave a lot to be desired. I *adore* your inspiration photo. Unfortunately, this is an exterior load-bearing wall, with a walkway outside (fire regulations), in a condo building, with a moisture envelope. I've learned the hard way that standard solutions for openings in load bearing walls don't work in this building because replacement vertical studs can't be tied into joists in a structurally/seismically acceptable way due to difficulty accessing the locations where those tie-ins would have to happen. I'm going to add curtains and hope that that visually widens the window a bit. Here's a very crude mockup (no counters, fronts, curtain rod, etc.): Edb2n, I think a small lamp or two on the counter might end up being a good solution for me. Dh will complain about it most likely, but I hope he can compromise a bit there.

There can definitely be compatibility issues between dimmers and LEDs. I found this on the Noralighting website which should be useful in making sure you have compatible dimmers. http://www.noralighting.com/Article.aspx?aid=1648 using a compatible dimmer should insure not only that you don't have buzzing, but that the dimming is smooth and exploits the full range of the light's capabilities (i.e. some lights can dim down to 1%, but with an incompatible dimmer may only get down to 20% and then abruptly turn off - this might be what your electrician is referring to).