# Re: How to translate log density readings to percent?

From: Dave Soemarko ^lt;fotodave@dsoemarko.us>
Date: 09/07/04-10:35:31 AM Z
Message-id: <02a701c494f8\$b25c2500\$0a808080@wds>

MessageLoris,

You do not need to map (Dmin, Dmax) to (0%, 100%). The values you have for R and 1-R are already in percentage.

That is, if you subtract the real Dmin (0.12) and consider Dmin to be 0, then at density of 1.33 the reflectance is 4.68%; the opacity is 95.32%. You do not map that to 100%. That would be incorrect.

Dave S
----- Original Message -----
From: Loris Medici
Sent: Tuesday, September 07, 2004 6:31 AM
Subject: RE: How to translate log density readings to percent?

I made a mistake and sent my previous message prematurely:

.
.
.

Mapped column formula is = ( 1 - R' ) / 95.32

OR, is it as simple as:

Thanks,
Loris.

-----Original Message-----
From: Loris Medici [mailto:loris_medici@mynet.com]
Sent: Tuesday, September 07, 2004 1:20 PM
Subject: How to translate log density readings to percent?

d = log ( 1 / R )

d: log density
R: reflectance (%)

=>

R = 1 / ( 10 ^ d )

d' R' 1 - R' Mapped
1 - R'
0,00 100,00 0,00 0,00
0,30 50,12 49,88 52,33
0,84 14,45 85,55 89,74
1,33 4,68 95,32 100,00
Received on Tue Sep 7 10:36:27 2004

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