Archived posting to the Leica Users Group, 2006/01/10

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Subject: [Leica] Underexposure in Tungsten Light
From: jblack at ambio.net (John Black)
Date: Tue Jan 10 09:18:38 2006
References: <p06230921bfe96e361e17@[10.0.1.2]><F5A7E4FC-1680-470E-A3FE-A0D3959F8A5C@mac.com> <p06230900bfe992d90a1f@[10.0.1.2]>
 

> Ah, so I'm not alone in this.  Next time I'll derate the film a stop
> and let you know what happens.
>
> I've seen the effect on both BW400CN and Fuji Press 400 (color neg).
>

All normal (not extended red or IR) film emulsions loose sensitivity
starting at about 620-630mu which means that tungsten illumination, which
tends to be reddish orange, is only seen at a lower sensitivity (speed).
Indeed, normal incandescent lighting needs 1 stop overexposure but some weak
tungsten light may need as much as 2 stops more exposure.  The light meter
sees red better than film does.

JB
Replies: Reply from r.s.taylor at comcast.net (Richard S. Taylor) ([Leica] Underexposure in Tungsten Light)
 In reply to: Message from r.s.taylor at comcast.net (Richard S. Taylor) ([Leica] Underexposure in Tungsten Light)
Message from kennybod at mac.com (Kenneth Frazier) ([Leica] Underexposure in Tungsten Light)
Message from r.s.taylor at comcast.net (Richard S. Taylor) ([Leica] Underexposure in Tungsten Light)