Re: Reading Dots & Density with a Spectrophotometer
Re: Reading Dots & Density with a Spectrophotometer
- Subject: Re: Reading Dots & Density with a Spectrophotometer
- From: Roger Breton <email@hidden>
- Date: Tue, 24 Dec 2002 11:11:01 -0500
Mathew asked:
>
>> Does anyone know of a great (ie. free) tool for reading dots and density
>
>> with an iOne?
>
>> P.S.
>
>> If ColorLab is the answer, which menu choice is involved?
To which Alex replied:
>
I know one way to use i1 as the densitometer: measure spectrum with
>
MeasureTool, save it to txt-file, open in ColorLab, Filter->Conversion->CIE
>
COlor->Density (DIN or ANSI). And you'll get 4 densities (for every CMYK
>
channels). Then you can save file as text, import to MS Excel and calculate
>
dot areas and dot gain in it.
>
Alexey Gribunin, UNIT Copier, Moscow, Russia.
Well, I believe a more direct route is to save the spectral reflectance
factor out of Measure Tool and go straight to Excel. Then setup a sheet with
the Status "X" spectral weightings you want to compute and do the
multiplication there. You'll have four multiplications to do, one for the
red filter (cyan), one for green filter (magenta), one for the blue filter
(yellow) and one for Visual (black).
Here's an example for the blue filter (ISO 5/3 page 15):
wavelength 350 360 370 380 390 400 410 420 430 440 ...
product 1.000 1.301 2.000 2.477 3.176 3.778 4.290 4.602 4.778 4.914
So, you see, to compute optical densities you need to multiply the
reflectance factor that you got from the EyeOne (less than 1.0) by the
corresponding wavelength weighting and sum all the products at every 10 nm,
from 350 to 760. The total should be the Status density.
Please someone correct me if I've got this wrong. Always willing to learn!
Roger Breton
Laval, Canada
email@hidden
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