Re: Can you answer this question?

["Barry Clark" <bajc@alphalink....au>]

Jan,

You appear to understand more about the subject than most lighting people
do.

The standards for lighting were devised by lighting people who get paid for
lighting things up.  They never want to be embarrassed by anybody
complaining that there isn't enough light.  The lighting manufacturers and
the power companies give them lots of encouragement.  Very few individuals
ever question the craze to turn night into day.

It is time to reassess all lighting standards from the environmental point
of view, particularly considering energy waste in the form of light
pollution and the need to reduce greenhouse gas emissions.

The Cinzano et al. paper in Monthly Notices of the Royal Astronomical
Society 328(3), 689-707 states that light pollution in most places is
doubling per decade.  Limiting magnitude observations in Melbourne confirm
this.  In fact this exponential rate has been maintained locally for many
decades.  It is time that the growth of outdoor lighting was brought under
control.  To get back to the situation in the Kyoto base year of 1990, about
half of all outdoor lighting needs to be decommissioned or the total usage
needs to be halved, or some combination of these.

It is also time that greater allowance should be made for the sensitivity of
older people to loss of visual performance from glare.

Good luck with the light pollution laws!

Barry Clark


----- Original Message -----
From: "Geoff Dudley" <gdudley@swin....au>
To: "Barry Clark" <bajc@alphalink....au>
Sent: Monday, January 28, 2002 12:12 PM
Subject: Can you answer this question?


> Message: 4
>    Date: Sat, 26 Jan 2002 19:27:48 +0100 (CET)
>    From: Jan Hollan <> Subject: non-FS and adaptation
>
> I suppose that one reason for the recommended (rather high) luminances
> and
> uniformities is a simple fact:
>  Using glaring lights spoils the eye (mesopic) adaptation.
>
> Why? Vertical illuminance of your face from distant luminaires is
> probably
> a lot higher than from the road. You may demonstrate it by shielding a
> white screen by a horizontal black cardboard -- over the cardboard, the
> screen is illuminated just from the luminaires, below it, just from the
> road.
>
> To see most detail on the road, the eyes should be adapted to its
> luminance. If they are forced by glaring luminaires to adapt to more
> light
> (and not just vertical illumination is important, luminance maxima
> inside
> luminaires play a role as well, diminishing eye pupils), less detail is
> visible on the road (or generally in the illuminated landscape). It can
> be
> compensated by more light, and very probably is, in contemporary
> standards.
>
> Animal vision is a fascinating tool, having no problem with twice lower
> average luminances, as far as fully adapted to them. Glaring luminaires
> prevent that (for the inevitable one above you, a visor (peak) on your
> cap or at your car's screen is a sufficient protection).
>
> Dark spots between glaring luminaires are really perceived darker than
> (maybe intrinsically darker) those ones between less glaring ones. This
> is
> the reason why uniformity is much less important with non-glaring
> luminaires.
>
> Am I true? Or, are there any standards accounting properly for
> adaptation
> (of non-fixed view, as fixing it all the time to avoid glare is really
> boring)? Are the contemporary roadway lighting standards really written
> (non-explicitly) as worst-case ones?
>
> (Of course I admit that all FS luminaires are not glare-free. Just the
> low-glare ones proportion among them is surely higher.)
>
> clear skies,
> Jenik Hollan
>
> PS.
>  your answer could help us to pass the LP law through Czech Senate next
> week.
>
> --
> Best regards,
> Geoff
> gdudley@swin....au
>
>