Seems like most of the good ones are using specialty fixtures/panels.
This was my first suspicion based on my early searches I was hoping for a cheaper alternatives and some better success stories using rope.
How much wainscoting are we talking about here? The entire room perimeter or just an accent wall?
Regardless of what you use, it's probably going to take a mock up to figure out the correct spacing of lights and the best method of assembly. Not sure if these would work or not. They may not be bright enough. Or they may be too bright and either require more distance between fixture and stone or perhaps some type of diffuser panel sandwiched between the lights and stone.
Thinking ahead to your installation-regardless of the type of light you use, you might want the lights mounted on some type of board that can be pulled out from behind the stone in case a section burns out or needs repair. A removable wainscot cap could provide access.
Is it solipsistic in here, or is it just me?
this was the inspiration photo that the client found
Just my two cents. I know it doesn't help solve the problem of how best to light the stone.
The rope lighting on the onyx is not perfectly even. If you knew there were rope lights under it and looked right at the onyx you could see the areas right under the rope lit up more. But basically the rope light is a mess of tangled rope behind the onyx so you get a randomish lighting pattern that looks perfectly good. There is a shelf under the onyx holding the rope light which is somewhere between 0"-2" behind the onyx. I think one of those full LED panel lighting setups someone linked above would be the more perfect solution, but I'm happy with the rope lights.
Thanks, hadn't thought about the randomness in placing the light.
Being a designer I know how that is and I didn't want to be the first one to say it...
Here is another suggestion: use an LED tape and aluminum bars to create something like this: http://www.tivolilighting.com/Products/ARCH_Products_/Strand_Lighting/Illumiwall.aspx
You can cut the LED tape every inch and then solder wires at the end to connect multiple sections together on a transformer. The tape I have used allows you to have 16ft of tape on one run. I've used a similar setup for under cabinet lights. The biggest issue I see is being able to dissipate the heat from the LED's. They get very hot. So, I would install the onyx panels with some spacers to allow air to circulate behind them. The aluminum bars help dissipate the heat, but you still need air flow. You can probably omit the horizontal section at the top and just have a series of vertical sections connected with #18 wire.
If you use a magnetic transformer, you can dim the LED's without special controls.
If you build it yourself is not:
60W transformer - $90.00 (you can drive two 16ft stings from this): http://www.amazon.com/Ledwholesalers-Dimmable-Magnetic-Transformer-Flexible/dp/B007KWVFXC/ref=pd_sim_hi_50?ie=UTF8&refRID=123YMHET6EPCQGDJ3MQ0
aluminum bar - about $3/ft: http://www.homedepot.com/p/Everbilt-96-in-x-1-in-x-1-4-in-Aluminum-Flat-Bar-56880/202183573
So the material is about $7 per linear ft. Assuming a 6" spacing between rows for good uniformity, it costs about $14 per sf.
I think this review is important to keep in mind:
Intended to provide some backlighting using LED strips SMD5050 (6 in total) cut back to 30". Spec for the strips says less than 6 amps/72 Watt for 196" - so I thought the 60W transformer would be adequate. It's not - needless to say that the temperature control switch triggered within the first hour of use and the humming noise was noticeable.
Upgrading to 300W instead has solved that issue - 150W might have been enough but I honestly didn't take my chances - the 60 bucks was just not worth it. Size the unit according to your use and leave room for contingency or make sure that you verify the consumption and not just trust the specs - would have saved me the money on the smaller transformer
It's a magnetic transformer with a bridge rectifier that works with a dimmer (on the primary side of the transformer, at 120V). If you don't need to dim the LED's, you can use any cheap switched mode power supply that outputs 12V.
A 300W transformer has a much better $/W ratio, so if you need more than two 90W transformers, look into the 300W version. Pay attention to the voltage drop though, if you end up with long runs.
The LED's get very hot, so they need a good heatsink. Other light sources usually use much more power than an LED, but with LED's all the power is concentrated in a very small area behind the chip. If you don't have a good heatsink to dissipate that heat, the LED's will burn-out very fast.