From: Scott Wainer (smwbmp@starpower.net)
Date: 01/29/03-05:31:36 PM Z
Ryuji,
I don't like the look of Kodak's new boxes either but for me Ilford has a
better pictorial quality. I think I confused the issue about sharpness and
left out the part about grain; my choice on Pyrocat is that the edge effects
are greater (increased "visual" sharpness) and the stain reduces "visual"
grain over conventional PQ/MQ developers. I tend to enlarge 35mm negs from
8x10 to 16x20 (or even 20x24) and, for me, Pyrocat can't be beat (yet?) in
the "visual" areas. I fully agree with you where LF (4x5) is concerned;
primarily because of the degree of enlargement.
As for ascorbate film developers, I tend to lump them with the PQ/MQ
developers. I do, however, use an Ascorbic Acid print developer (Chris
Patton's E-72) which is considered to be of the Dektol type.
The "thickened" developer sounds interesting; I haven't heard of it before.
Could it be used with a developer like Pyrocat? I might like to try it with
4x5 film using the dip-n-dunk method. How would the developer react to
gelatin or gum arabic as the thickening agent (I don't have any
methylcellulose handy)?
Scott Wainer
smwbmp@starpower.net
----- Original Message -----
From: "Ryuji Suzuki -- JF7WEX" <RSuzuki@MIT.EDU>
To: <alt-photo-process-l@skyway.usask.ca>
Sent: Wednesday, January 29, 2003 2:47 AM
Subject: Re: Acros Films
> From: Scott Wainer <smwbmp@starpower.net>
> Subject: Acros Films
> Date: Tue, 28 Jan 2003 23:43:11 -0500
>
> > I do not like the look of images from Kodak films so I generally
> > shoot Agfa or Ilford.
>
> I think it's a quite strong comment :-) I don't like the box design of
> new Kodak films, so I haven't really seriously tested any. But I think
> films are good, at least pre-2002 Plus-X and TMX are my favorites. The
> sodium sulfite argument generally repeated and copied may or may not
> apply, and Plus-X is a good case where I think stock D-76 gives you
> very good sharpness with very fine grain. I've tried to make MANY
> developers for Plus-X just because I like the film, and I make
> side-by-side comparison of 14x magnification agaist the strip
> developed in D-76H (I usually cut sulfite to 80g and add a bit of
> bromide, and make it buffered to pH of 8.60 pm 0.05, but this
> modification is not very important) but even accutance developers give
> me simply grain-enlarged image with no increase in imagewise
> sharpness. If this gives desired effect for your image, it's fine, but
> I wouldn't say the image sharpness was enhanced. (80g/L of sodium
> sulfite maximizes solvent effect, especially when bromide is
> present. In absence of bromide, the difference is practically
> negligible.)
>
> I think TMX is a bit more tricky, and some mild accutance developers
> help to take advantage of TMX's very good resolution (but not
> necessarily very good perceived sharpness).
>
> > My mainstay is landscape/architecture and I find the catechol gives
> > sharper/grainless images when diluted 1:1:400 using
> > stand-development between 50-90 minutes.
>
> If you mostly do LF, I think you can practically ignore grain unless
> you make huge blowups, but I work mostly with 6cm square (new Mamiya
> 6, not the folding camera) so I value fine grain.
>
> My experience with stand development is not very positive either. I'm
> also skeptical about the notion of "compensation" with modern
> films. I'm also skeptical about the benefit of two bath development
> with modern films. But I like modern films :-) I don't know why.
>
> The "compensation" is supposed to be due to exhaustion of developer in
> highlight areas. But modern films contain agents to facilitate
> diffusion of developing agents, and to facilitate adsorption of
> developing agents to silver halide surface. Also, if developping
> agents are to deplete, the rate of chemical development must be pretty
> large compared to above two factors. In extremely dilute developers,
> modern films raise contrast too slowly for this to be likely. In
> addition, film curve in highlight-shoulder region seems mostly
> determined by sensitizing agents and other factors during emulsion
> making. Some people told me compensation works well with greatly
> reduced agitation, but I don't like the idea of reduced agitation --
> too risky. People told me time to time some combinations worked well
> for them, but I'm not certain how reproducible they are.
>
> Edge effect is a different issue, because if you make the developer
> rather sensitive to bromide, which is released from vigorously
> developing crystals, you get some adjacency effect. Again, if the
> development is not rapid enough, bromide can diffuse out to bulk
> solution before it makes any effect. My metol-ascorbate-carbonate
> developer was aiming at this.
>
> This solution consists of 0.4g metol, 1.0g ascorbic acid, 1.0g sodium
> bicarbonate, 4.0g sodium carbonate monohydrate, 20g sodium sulfite in
> one liter of water. I like this developer very much, but it does not
> keep well, even if you make a split solution and keep ascorbic acid
> very acidic. I did some library research on ascorbic acid chemistry,
> and posted a midterm report to pure-silver but I haven't made a final
> report yet. I think the reason ascorbate developers don't keep is iron
> impurity in chemical agents, especially sodium sulfite. Photographic
> grade sodium sulfite may contain 10ppm max of iron, and another 10ppm
> of heavy metals as lead equivalent. This is more than enough to act as
> oxidation catalyst for ascorbic acid. I've been working on
> modifications to prolong shelf life. (Sulfite's preservative action is
> very slow at room temperature) One usual strategy is to chelate iron,
> but this turned out to be a bad idea. Chelating iron just means
> keeping iron in solution, and it does not mean it inactivates iron.
> Then, EDTA chelated iron is more active catalyst than bare ferric
> iron. (XTOL uses DTPA as the chelator, but I don't have DTPA and I
> don't know if it helps or hurts.) Also, the developer's pH range is
> not ideal for most commonly used chelators, including EDTA and
> DTPA. (there is a very effective iron chelator used to treat iron
> poisoning but it's impractical for photographic developers.)
> Unexpectedly, I observed that very alkaline developer lasted just as
> long as very mildly alkaline developer. So I got some idea, and tried
> to add phosphate to make very insoluble iron compounds and precipitate
> iron out of the solution. Also, ascorbate makes reversible complex
> with borates (the same mechanism as the one where borate inactivates
> pyrogallol or catechol) and this provides protection for ascorbate.
> There are a few other potentially useful ascorbate esters but I didn't
> try them. I also make print developers (for silver-gelatin) based on
> the same idea, which gives me a very long tray life. Anyway, I
> shouldn't write too much bad thing about iron in alt-process list :-)
> If there's any chemist formulating practical ascorbate developers, I'm
> willing to exchange information.
>
> Here's one idea for sharpness junkies. Almost any photographic
> chemistry book mentions "thickened developer" which is basically a
> fine grain developer thickened with thickening agent such as
> methylcellulose. The increase of sharpness is clearly stated. It's not
> too surprising if it also gives compensating effect. There are two
> problems. One is that this developer is very difficult to use because
> of very viscous form. How you develop a rollfilm? (spiral reel is not
> a very good idea. Maybe a real deep tank and a hunger? Then nitrogen
> burst wouldn't work. Some people suggested to make one with a black
> PVC pipe.) Another is that there is no known replenishing method that
> does not need to discard a lot of thickening agent. I was pursuing
> this idea but my priority moved to something else. I think motion
> picture industry would have loved the idea of increased sharpness, but
> I don't think it was ever used in practice. (Richard, know any?)
>
> Wrote a bit too much :-)
> --
> Ryuji Suzuki
> "You're crazy man, there's no one here but me and my machines!" (Neil
Young)
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