Amazement

[bookers]

I'm amazed to read so much varying information about lighting in a woodworking forum!
As a lighting engineer/ designer/ salesman for some 15 years now I'd though I'd throw in my 20c worth over flourescent and low voltage light sources.

Firstly we need to understand two main criteria about lighting.
Colour Temperature.
This refers directly to the appearance of the lamp (Colour), how WE see it, and is measured in degrees kelvin.

Normal GLS lamp - 2900k (which is 2900 degrees kelvin)
Low Voltage - 3000k approx.
Warm White Flourescent - 3000k approx.
Cool White Flourscent - 4000k approx.
Daylight Flourescent - 5000-6500k approx.

Colour Rendering.
This refers to the way the light source reproduces colour. This is measure by the CRI colour rendering index. Natural daylight being 100

Normal GLS lamp - Above 80
Low Voltage - Above 80
Flourescents (Triphosphor) Above 80

Bearing these two important factors we can see that both Flouro and LV can both reproduce colours admirably it is only the colour of the light source we see is different.

LV vs Flourescent.
Watt for Watt Flourescent is the clear winner.
50w LV lamp also has .8w for the transformer. A 36w Flouro also has 5.5w in ballast losses.
Next we have to look at distribution of the light. A 36w tube is 1200mm long. As opposed to 51mm diameter of the LV therefore 'spreading' light over a greater distance.
In terms of intensity the LV lamps win hands down as more light is directed to the working surface in a smaller beam spread.

Aesthetics.
Obviously the smaller LV's appear alot nicer however the key to a good lighting design is to not see the light! Lighting companies are continually creating new fittings for domestic use to combat these downlight incorporating a Compact flourescent lamp. Which is available in the same Colour temps and uses even less power. A 9wPL is the equivalent to a 40w GLS lamp.

Maintenance.
LV lamps work on the basic principle of heating a wire element to create light. This wire filament is extremely prone to breaking due to many factors such as voltage spikes/ surges, line interference, continual switching and vibration from transportation. They generally have a rated life of 2000-5000hrs.
Flourescents are a gas discharge lamp that is not subject to the above mentioned problems and can last anywhere from 8000 - 20,000hrs. Although they do have their problems but nowhere near as many.

Each light source and fitting has there own specific uses and alot of times comes down to personal preference. 'The customer is always right, even when their wrong.'

If anyone want's me to bable on any further I'm more than happy to talk further on lamps, control gear or fittings.

Thanks,

[jackiew]

I think I'm right in believing that if you're aiming for a nice dim romantic light you need to use an incandescent as the compact fluorescents can't be dimmed?

if anyone is having problem making out fine detail under artificial light when in daylight they know that they wouldn't have a problem I suggest trying a "daylight spectrum" bulb ( note these are incandescent not fluro ). They aren't cheap but in my experience its worth the money. If you can't find one where you normally buy your light bulbs then try shops which sell knitting supplies - ever tried to pick up the dropped stitches on a black jumper under artificial light :eek: If it doesn't improve things you can give it to someone who does knitting/embroidery as a present ( just don't tell them you tested it first )