Re: Beginner Density Questions & Digital Negs

Thanks a lot Christina & Loris,

Ok, so 1.9 refers to the density range. So then how do you arrive at this
number? Is this only a number that those using a densitometer can define?
Regardless, I'm still interested. If you did have a densitometer, do you
then measure the darkest part in the neg, and then the lightest part of the
neg, and that the difference would give you this number? Or would it give
you this number with B+F (which brings me to my next question).

What are base density and fog density (if I were to guess I'd say the base
density is the density of the media itself, but fog density)? Are these
figures generally given by the manufacturer? What is the B+F of Pictorico
OHP?

Christina, how did you arrive at the colour you use for your negs? I have
read Clay Harmon's approach (using the triangles)...is this the easiest?

I'm waiting for some money to come my way before I attend a workshop with
Mark. I've been thinking about it for a little while but want to try and
have the basics out of the way as much as I can to be able to take advantage
when the time comes.

Mark, if you're reading this...I'm trying to make it! Don't count me out
yet.

Thanks again,
Gu

On 5/16/06 9:48 AM, "Christina Z. Anderson" <zphoto@montana.net> wrote:

> Gu,
> Loris is right--that a 1.9 refers to density "range". Some processes
> require a huge density range such as platinum. Some, such as gum and
> cyanotype require a more compressed density range. A lot of the books will
> describe it as a negative that prints on a grade 0 paper or a grade 2 paper
> to differentiate between those processes that need a greater to a lesser or
> a more normal density range.
>
> I will add my two cents about the 2400 since that is now my printer. I
> think originally, Gu, you asked a question about colorized negatives. I
> have found in using the 2400 that the black ink is less dense than the
> colored inks in that printer and by comparison to the Epson 2200, the black
> is not as dense as the black ink in the Epson 2200 which I used to use, but
> the colored inks are more dense than the Epson 2200 colored inks by a bit.
> This is fine, because I don't use black ink in my negatives. The 2400
> prints beautiful color-only negatives that work for all processes.
>
> Depending on the process you are doing, you have to be aware that with alt
> processes, it is the UV density of the digital negative that comes into
> play, not just the blocking density. Hence, a color may look pale in
> comparison with black ink, but actually hold back lots of UV light in
> contact printing processes. I don't have a transmission UV densitometer,
> and therefore can only find this information out by printing step wedges and
> scanning and measuring reflective values on a flatbed scanner.
>
> There are a number of ways to go with digital negatives, in my mind. For
> one, go to Dan Burkholder's website and download a curve (plus his myriad
> other tiny tutorials which are worth every penny--I had students this
> semester using his platinum over pigment process and producing gorgeous
> work).
>
> Two, go to Mark Nelson's precisiondigitalnegatives.com site and purchase his
> software system which enables you to create custom curves for every
> process--more work to do but in the long run it is a necessary tool to
> understand how digital negatives work in all processes with all different
> printers. If I can teach it to 16 students who produced perfect platinum
> prints in their first try, you know it works. Not one of them complained
> about the $75 cost after they saw the results.
>
> In fact, I have seniors waiting to take their last allowable junior level
> class for a year just so they can be assured of getting into the alt process
> class next spring (we have waiting lists on all classes and that class in
> particular only accomodates one section of 16)! And I don't think it is for
> my scintillating personality.
>
> There are also a couple other people who have developed a personal method of
> digital negative making--Clay Harmon on this list is one, and google his
> name. I heard of one other person coming up with a system that you could
> also try, but I forget at the moment his name.
>
> The bottom line is that not only do you have to find the correct ink to
> hold back light, but you also have to use the correct curve that is smooth
> and fully tonal so you don't get steps/jumps/posterization. You don't want
> bumps in your curve.
>
> You know, is everyone on vacation or WHAT? Get those fingers moving you
> people!
> Chris
>
>
>
> From: "Loris Medici" <mail@loris.medici.name>
> Michael, I don't agree with you on the fact that the cited 1.9 density
> range figure is referring to the reflective density of the print. In my
> understanding the 1.9 figure refers to the density range of the
> negative. And when one talks about density range this means the absolute
> dmax of the negative should be even higher: For instance, if the
> negative material's base + fog density is log 0.3, then the absolute
> dmax of the negative should be 0.3 + 1.9 = 2.2 - that is for being able
> to print a full tonal image by using the specific process (and/or
> coating solution/emulsion mix) which requires a negative density range
> of 1.9. IME, it is impossible to get a printed density range of 1.9 with
> palladium - this is closer to what you can get from air dryed fiber
> based glossy silver-gelatine paper! I can't get such a printed density
> range even after coating my palladium prints with glossy polyurethane
> wood finish... (which improves dmax by log 0.3 - 0.4 / over regular
> uncoated prints).
> On the other hand, with print-out palladium (ammonium iron(III) oxalate
> sensitizer + Li2PdCl4 - that is Ziatype w/o any contrast agent) the
> negative density range requirement is considerably higher than 1.9.
> (This is probably true for develop-out palladium also...)
>
>
>
>
Received on 05/16/06-02:55:17 PM Z