Digital BW, The Print

----- Original Message -----
From: "John Brownlow" <lists@...>
To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
Sent: Wednesday, March 27, 2002 5:43 PM
Subject: Re: [Digital BW] Dynamic Range Definitions and Print Tones


> On 3/27/02 mwesley250@... wrote:
>
> >For all practical purposes a print existing as an object separate from
> >the process that produced it seems to be noiseless and the dynamic range
> >is the ratio of the min and max reflectance or the difference of min and
> >max density.
>
> no, by the definitions you cite, the variation in the reflectance of the
> substrate (paper) is the noise floor. Since the paper is not perfectly
> white, there is a limit to how delicate the highlights can be before they
> are more delicate than the variations of the paper itself. Therefore the
> choice of paper may have a large effect on the dynamic range of the
> printing system.
>
John,

I like that! Finally a concept of noise for a paper print. There is probably
a similar variation or mottle in the deepest black so you have a noise floor
and a noise ceiling.

If you pick up the newspaper you can easily see the base brightness
variation. There would seem to be an obvious difference between an art paper
like H. German Etching or William Turner and Epson Photo Paper just because
of the texture.

There would be two factors to this noise the amplitude and the frequency as
you moved across the paper surface. I know that the spot size measured by
the densitometer I have used would not be small enough to pick this up in
quality papers and I doubt even the really good ones would be able to spot
the variations in brightness. I suspect that the surface variations you are
talking about would be less than the uncertainly of standard instruments.

I have no idea what the magnitude of such noise might be. From the papers
you have worked with do feel that you can see this as limiting property on
the quality of your prints?

Martin