Archived posting to the Leica Users Group, 1999/09/25

[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]

Subject: Re: [Leica] OT was: Low Pressure Sodium
From: "Anthony Atkielski" <>
Date: Sat, 25 Sep 1999 11:25:58 +0200

From: Michael D. Turner <>
Sent: Saturday, September 25, 1999 04:41
Subject: [Leica] OT was: Low Pressure Sodium

> However, it is amazing what can be recovered providing
> it has been recorded (and still exists).

Even in ordinary digital images from cheap digital cameras, I've been surprised
at what can be extracted from apparently featureless shadows or highlights.
Even scanned snapshots can be enhanced to show things that weren't originally
there (visibly).

> You can't reproduce detail that does not exist.

But no detail at all is rare.  Low-pressure sodium is one of the few situations
in which there is no detail at all.  Actually, it's no so much that there is no
detail, as that the detail in all three channels is proportionately the same, so
there are no differences that can be exploited to recover actual color.  Not
surprising given that the LPS spectrum is bright-line and monochrome.  I hate
LPS lamps.  I guess they'd be okay for black and white, though.

  -- Anthony