Digital BW, The Print

I wonder if we're all talking about the same thing. My understanding is that
metamerism and "bronzing" are the same, i.e., a printed image viewed from an
angle (usually), displays a metallic-like bronze-tone in the darker ink areas,
creating an almost posterized or negative image in the worst case. Chromaticity
(as it explained to me by the Cone Editions lab manager) is when ink reflects
differing coloration, depending on the viewing light source... the coloration
usually being crossovers such as magenta or green. If I'm incorrect, please
don't hesitate to set me straight.

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----- Original Message ----- 
From: harrisimages
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Sent: Friday, July 25, 2003 6:23 PM
Subject: [Digital BW] Re: Imageprint for B&W


I have been using ImagePrint for some time on a 2200.  I see
essentially no metamerism when printing B&W. At 50,50 tinting, the
image is slightly warm, but nearly neutral.  In fact I see more
metamerism when printing B&W using PiezoTone Selenium Tone inks on
my 1280...yes, there is some very slight metamerism, although it is
not objectionable...with PiezoTone.  Metamerism is not an issue when
printing B&W with ImagePrint.  This is because yellow ink is not
used, and it is said to be the primary cause of the metamerism using
Ultrachrome inks on the 2200.

Ron
www.harrisimages.com


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Rick Colson
<colson@i...> wrote:
> IMHO, ImagePrint may give you a great B&W print with a 2200 (or
7600/9600
> for that matter) but metamerism will rear its ugly head in
different
> lighting situations and your 'neutral" B&W print will only be
neutral in a
> narrow range of lighting conditions.
>
> Rick



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[Non-text portions of this message have been removed]

Bronzing and metamerism are not the same.  Metamerism is the 
apparent change of image tone under different light sources, such as 
incandescant lighting and ambient window lighting.  B&W prints made 
with color inks on the Epson 2200 using the Epson driver suffer from 
metamerism.

I print B&W using ImagePrint on the 2200 using matte papers and 
matte black ink.  No metamerism, no bronzing.  Bronzing typically 
occurs with glossy papers, which I don't print on.  Others will have 
to address this question.

Ron
www.harrisimages.com

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Ken Schuster" 
<ken.schuster@a...> wrote:
> I wonder if we're all talking about the same thing. My 
understanding is that
> metamerism and "bronzing" are the same, i.e., a printed image 
viewed from an
> angle (usually), displays a metallic-like bronze-tone in the 
darker ink areas,
> creating an almost posterized or negative image in the worst case. 
Chromaticity
> (as it explained to me by the Cone Editions lab manager) is when 
ink reflects
> differing coloration, depending on the viewing light source... the 
coloration
> usually being crossovers such as magenta or green. If I'm 
incorrect, please
> don't hesitate to set me straight.
>

Where does "chromaticity" come in?

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Help end spam and telemarketing... never respond to it.

----- Original Message ----- 
From: grdglass@...
To: DigitalBlackandWhiteThePrint@yahoogroups.com
Sent: Saturday, July 26, 2003 7:19 AM
Subject: [Digital BW] Re: Imageprint for B&W

Metamerism and bronzing are not the same thing.  Metamerism is the change of
overall color under different lighting.  The entire B+W print would appear
greenish under daylight and magenta-ish under tungsten.  Bronzing produces a
"shine" on only dark areas of a print because of differing ink laydown
properties.

You see bronzing with manipulating the print at various angles to the light.
Metamerism is seen "straight on."

Helene


[Non-text portions of this message have been removed]

Ken Schuster wrote:

>I wonder if we're all talking about the same thing. My understanding is that
>metamerism and "bronzing" are the same, i.e., a printed image viewed from an
>angle (usually), displays a metallic-like bronze-tone in the darker ink areas,
>creating an almost posterized or negative image in the worst case. 
>
Nope, bronzing is generally from ink overloading and/or ink remaining on 
the surface.. What you describe is bronzing, not metamerism..

>Chromaticity
>(as it explained to me by the Cone Editions lab manager) is when ink reflects
>differing coloration, depending on the viewing light source...
>
Correct..

> the coloration
>usually being crossovers such as magenta or green. 
>
What you are NOW starting to describe is metamerism..

As I understand it, chromaticity is simply the tendency of reflected 
color to vary in accord with the variance in viewing light hue.

Metamerism occurs when the chromaticity of differing color inks behave 
in ways that result in cross-overs or non-proportional color changes at 
points in the reflected light. 

If I view an apple under a blue-white light it looks more blue than 
under a tungsten light. But, since the color changes are relatively 
proportional and crossover free, my mind adjusts  the image in differing 
lighting to accord with the mind's image of a bright red apple.  In a 
non-metameric print, you can take it into differing lighting situations 
and your mind will adjust what it perceives to accord with the hue 
shifts seen in other observed objects.

However, with a neutral print, if I take the print into daylight and it 
looks green, while in roomlight it looks magenta, what has happened is 
that the changes either have crossovers in some portion of the reflected 
spectra or have become widely disproportional, so my mind doesn't and 
can't automatically adjust o keep what I view seemingly perceived with 
the same hue as it had under another light source...

 

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User Community (highly recommended by Vogon Poets and MegaDodo 
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