U of S | Mailing List Archive | alt-photo-process-l | Re: Gum tonal range (was Miracle size for gum)

Re: Gum tonal range (was Miracle size for gum)

Wow, this is like Alice in Wonderland; the question arrived after I sent the answer.

Yes, you're thinking right: with multiple printing there are no limits on what gum can do. Isn't it a wonderful process?


On Oct 12, 2009, at 4:15 PM, phritz phantom wrote:

i've been wondering, is this discussion about exclusively about one- layer-gums? i think it is.
single layers of gum have a rather short tonal scale, i think we all agree on that. but so what? hardly anyone actually prints single layer gums, except for testing, experiments... so with the inifinite amount of layers i can add, the tonal range of gum is only limited by the pigment. and the smoothness / contrast depends on how good those layers are coordinated.
katharine, with your .75 density range, did you mean single layer or finished print?

the other thing is, that all tonal ranges are a continuum between black and white. there aren't any steps in reality. even in an extremely short tonal scale is every single shade of grey present in it. it's just a matter of a suitable negative to print them.
or am i getting something wrong here?


Paul Viapiano schrieb:

I've now worked with several different DRs with *my* gum prints...
Although the lower DRs are great for one-layer prints, I find the pt/pd negs (1.8 and up) give me more breathng room for accurate separate exposures for highs, mids and lows. It's easier to divide a 7 or 8 min exposure (I use the sun) into separate components than a 1.2 neg that has a base exposure of 2 - 2 1/2 minutes.
----- Original Message -----
From: "Loris Medici" <mail@loris.medici.name <mailto:mail@loris.medici.name>>
To: <alt-photo-process-l@usask.ca <mailto:alt-photo-process- l@usask.ca>>
Sent: Monday, October 12, 2009 12:38 PM
Subject: Re: Gum tonal range (was Miracle size for gum)

For the sake of clearness I'd add that no one had made such a
translation as I understood the conversation. The subject was "what's
the *ideal* negative DR" to print gum, and when somebody says "gum
prints 2 stops", what I understand personally is that they're making
the assertion: "gum need a negative density range of log 0.6", which
is obviously a false statement. Gum is so flexible that one can print
perfectly from a negative with a density range 0.6, or 1.0, or 1.2, or
1.5, or even 1.8 as Marek shows, (fill the rest and in between), given
the necessary adjustments in emulsion formulation / exposure and
development are made. That's my whole point - which I'm sure you'll
agree. What's best depends on the practitioner and their particular
workflow / strategy of preference. Hence the (*)s to mark "ideal"
above; there's not an ideal DR in the practical sense. Especially
after some amnt. of experience...


2009/10/12 Katharine Thayer <kthayer@pacifier.com <mailto:kthayer@pacifier.com>>:
> ...
> I was not arguing against the use of step wedges, for heavens' sake;
> ...
> I was simply arguing against the translation of number of steps, or the
> number of "stops" to a print density range by multiplying by .15 or .30.
> Hope that point is now perfectly clear.
> ...