Re: Re: Digital reply


FotoDave@aol.com
Sun, 10 Jan 1999 23:15:51 -0500 (EST)


In a message dated 1/10/99, AM 10:35:17, nadeaul@nbnet.nb.ca writes:
<<As mentioned in the repost that Judy just made, I did get some 200 small
prints from an Iris (which btw is only 300 dpi) on Palladio paper. Palladio
gives good results from "normal" (for silver printing) negs.. The quality
is excellent, i.e., just one notch below what I call "superb".

Hi Luis,

I don't do Palladio, so I don't know what kind of negatives one need for
Pallodio. When you say "normal" do you mean about normal contrast for silver
paper? A normal negative has a density range of 1.20 to 1.50 for average
scenes. Most of my negatives have even lower range, thus it is easier to make
digital, binary dots with inkjet dots which has density close to 2.0.

But for emulsion that has exposure range of 1.8 to 2.0 (as I have read), this
is very difficult. Exposure must be, theoretically, exact and right because
over exposed a little, the clear area starts to have density. Underexposed a
little, the densed area doesn't get dark enough.

As I have said (and posted a diagram) about half a year ago, digital negatives
consists of dots. If we have a 480000 dpi printer and our emulsion can resolve
that resolution so there is no visible dots under 1000x magnification, they
are still dots. They visually merge into continuous tone, but they DON'T
physically merge into continous tone. They are dots are dots are dots. This is
important to remember (it affects how one coats the emulsion, what range one
desires, etc.) in making prints from digital negatives, whether it is in
Pt/Pd, carbon, or gum.

I have to make a small correction to my previous statement:

******* To get enough density on the acetate, all four colors had to be
> used but the resulting negative was not a perfect neutral grey. He
> found that by adding a certain tint he could make substantial contrast
> adjustments on his pre-coated Palladio paper.*******

This is still going to be difficult for a long-range process like Pt/Pd. It
might be doable, but I mentioned, exposure must be exact and it is at the
theorectical limit, and we know in real life things are more difficult than
the theoretical limit.

The reason is because while one achieves higher density with 4 colors,
remember that density is the average density of a small area of the opening of
densitometer. In other words, if you measure a density of 3.0, this is
different from a 3.0 density given by an imagesetter. An imagesetter can give
you a dot with density 3.0, but an inkjet printer will give you 4 dots, some
of them overlap, some of them don't and each one will have density less than
that requried for Pt/Pd, so the non-overlapping area will give trouble as
described earlier.

(an extra note so that some won't misunderstand me, I am not arguing about the
use CMY vs CMYK, honestly, because this discussion has started about 1-2 years
ago. It is not about printing an image using color pigments, it is about using
CMYK to print a b/w image on transparency to be used to print a b/w print. The
reason is because some say that it will give higher density for long-scale
process).

>I meant "screenless". You do see a random grain but no regular screen
pattern.

I understood it that way since your post specifically talked about inkjet
printer. With the resolution of a desktop inkjet printer, I don't think one
can achieve grainless prints.

>> Since the new 6-color inkjets can give full scale reflexion copies, I don't
see why paper negatives couldn't be used to provide excellent continuous
tone carbons or platinotypes.
>>

Again, the full scale is because of visual mix, not physical mix.

Well, I am not trying to say that it is completely impossible (as it is close
to limit but probably still within workable limit). One might try a lot and
make something work but it might not be as easy as one thinks.

DS



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