[rollei_list] Re: Plus X -PX 125- and Microdol X discontinued
- From: Mark Rabiner <mark@xxxxxxxxxxxxxxxx>
- To: <rollei_list@xxxxxxxxxxxxx>
- Date: Thu, 18 Feb 2010 11:25:11 -0500
>
> ----- Original Message -----
> From: "Mark Rabiner" <mark@xxxxxxxxxxxxxxxx>
> To: <rollei_list@xxxxxxxxxxxxx>
> Sent: Wednesday, February 17, 2010 8:24 AM
> Subject: [rollei_list] Re: Plus X -PX 125- and Microdol X
> discontinued
>
>
>>> My personal preference in printing is for absolutely no
>>> noticeable grain in
>>> the print, which I can accomplish through a Leica, HC110
>>> and an 11 X 14
>>> print maximum.
>>>
>>> Marvin.
>>
>>
>> The only problem with developer dilution combinations
>> which give you fine
>> grain is they give you poor acutance. There is some
>> degrading of image.
>> Usually form sulfite eating away at your grain. One not
>> getting their cake
>> and getting to eat it too.
>> From a Rollei medium format neg grain should not be an
>> issue with acutance
>> developers in any size you're likely to print.
>> I'd try some acutance developers you might find the
>> clarity might overweigh
>> some slight notability of grain you might experience that
>> you were not used
>> to. It will be very faint but sharp and regular. Not mush
>> grain which has
>> been eaten away at by sodium sulfite.
>> With high sulfite developer dilutions one wonders what the
>> point is
>> obsessing over Zeiss vs. Schneider vs. anything glass
>> you're not going to be
>> experiencing the highest common denominator.
>>
>>
>> [Rabs]
>> Mark William Rabiner
>>
>>
>>
> I really need to get into this. The solvent action in
> developers with a lot of it does not dissolve any of the
> developed silver grains. What it does is to change the
> morphology of the grains and their distribution in the
> emulsion. Developers like D-76 or even D-25 do not affect
> the resolution of the film. The effect on acutance is due to
> the prevention of reaction products of development from
> affecting the rate of development at sharp discontinuities
> of the image. Some reaction products act as restrainers.
> Metol is such a developing agent. Some act as accelerators,
> for instance those of hyroquinone. In fact, the accelerating
> action of hydroquinone reaction products is one reason it is
> used in very high contrast developers. These reaction
> products are proportional to the image density. So, where
> there is a sharp demarcation between a high and low density
> the reaction products in the immediate vicinity tend to
> either restrain the development on the low side or to
> accelerate it on the high side. In some developers both
> happen so that there is a very localized increase in
> contrast around the demarcation. The scale of this effect
> depends on the rate of diffusion of the reaction products in
> the emulsion and are fixed in size so that they make much
> difference for small than large negatives.
> Sulfite tends to prevent oxidation of the developing
> agents, which are reducers and tend to oxidize easily. It is
> the oxidation which occurs during and because of development
> which produces the reaction products and thus the acutance
> effect. The more sulfite the less the reaction products
> produced or the faster they recombine. This effect of
> sulfite is separate from its effects as a _halide_ solvent.
> It has a second grain reducing effect, namely the "salt"
> effect which helps to prevent emulsion swelling and the
> attendant grain migration which results in grain clumping.
> Modern emulsions do not swell much so the salt effect is
> less than in the past. Other salts in the developer also
> contribute to the salt effect including carbonates and boron
> compounds like borax.
> The effect of the solvent action is complex. It changes
> the way the metallic silver particles are formed out of the
> halide crystals. In a low solvent developer the silver
> crystals tend to be the same shape as the original halide
> ones. In a high solvent developer they tend to form as very
> fine filiments which have higher covering power than the
> simple crystals. Depending on the amount of solvent it can
> also increase or reduce film speed. At moderate
> concentrations, as in D-76, the solvent can increase speed
> somewhat because it etches the surface of the halide
> crystals and makes more development centers available to the
> developer. If the solvent effect is increased, as it is in
> D-25 by its low activity, it can actually destroy some of
> the development centers resulting in some loss of speed. The
> solvent action does not account for speed or grain by
> itself: the developing agent also has an effect. For
> instance, paraphenylenediamine, which became popular in the
> early 1930s for 35mm film produces extremely fine grain but
> looses as much as 5 or more stops of speed if used alone.
> PPD is an effective halide solvent and this may account for
> its loss of speed, at least in part. Orthophenelynediamine,
> which is not a developing agent, was used in some fine grain
> developers primarily as a solvent where something else,
> often Metol was used as the reducing agent. One of the
> Windisch formulas contains it.
> In any case it is certainly true that high sulfite
> developers tend not to have acutance effects. But the main
> cause of "mushiness" is the lack of resolution of the film,
> the lens, or both. Keep in mind that to get good resolution
> on an 8x10 print from a 35mm negative requires something on
> the order of 60 lp/mm on the negative at reasonably high
> contrast. That is hard to do considering both film and lens
> have to have about double this value. This is one reason
> that getting results from 35mm that are comparable to almost
> anything larger is very difficult.
>
> --
> Richard Knoppow
> Los Angeles, CA, USA
> dickburk@xxxxxxxxxxxxx
>
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Many serious workers do not use solvent developers they use acutance
developers.
But a few do they use solvent developers formulas at higher dilutions. Even
higher than normally listed and receended on the box.
It at a higher dilutions these formulas can come close to emulating acutance
formulas. Like Beutlers. Which has 5 grams of sulfite in it - not 50 or 100.
[Rabs]
Mark William Rabiner
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