Digital BW, The Print

>  From: Jon Adams <hi5photos@...>
 
>  I am a little confused about metameriam. Is that
> the effect one gets when viewing a print from a
> variety of perspectives where it appears that the tone
> of the inks seem to change?

The standard explanation for metamerism is a condition where you have two
samples that measure the same color (if you used a Spectrophotometer) but
appear differently due to the light source and how it interacts with the
sample. Keep in mind that there are three areas you need to consider when
talking about viewing color: The light source, the subject and the viewer
(you and I). 

Metamerism isn't a bad thing, in fact if we didn't have it, there would be
no way we could match two distinctly different samples. Obviously with good
color management, we can make two devices match each other so in this case,
metamerism works to our advantage. In the same token, one could say
metamerism is the condition where two different samples produce the same
color appearance (is the glass half full or half empty?).

Where metamerism is a pain is the situation where you might print something
out and find that under a 5000K lightbox, you love the color only to find
under tungsten, the appearance changes (one of the three factors, our light
source is now different).

One reason having a "standard" viewing condition (your 5000K lightbox) is
useful is to be able to view all kinds of samples under one kind of
lighting. Yes, a client may take the print to a totally different light
source and the pigments or something else may produce metamerism that ends
up with a print that looks vastly different. Par for the course.

I suspect all media undergoes different degrees of metamerism. When you view
your Epson 1280 dye based ink print under two light sources, the degree of
metamerism is far less than when you view pigmented inks from a 2000P.

Andrew Rodney 

Andrew Rodney