Re: [ATM] Dark finish for a telescope tube

[hermit <hermit@outofoptions.org>]

Michael Wheatley wrote:
> You would not learn much from a densitometer or a sample in a dark 
> room but it should be easy to get useful information with a 
> flashlight and a spot meter.
>
>   
A densitometer is a highly precision instrument for measuring
reflectivity.  Phil Davis in his book does give a method for converting
a spot meter for use.  The densitometer uses a fairly bright light. 
That helps it detect very black surfaces.  There is a reason gloss black
LOOKS BLACKER.  We assume since we can see reflections it is a 'bad'
thing but if the matte reflects overall more light, which is worse? 
Isn't it better to use the gloss and control the reflections?

Ken Lowther
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