From: Richard Knoppow (dickburk@ix.netcom.com)
Date: 07/17/02-06:12:57 PM Z
At 02:34 PM 07/17/2002 -0400, you wrote:
>
>>I process in straight D-76 in a homemade BTZS-style tube,
>> >at 68 degrees. I am thinking maybe I should make the temperature warmer
>>>rather than making the times longer. But, then what will I do if I ever
>>>have to increase the development time further for a low-constrast scene?
>>>(Excuse the cross posting if you read
>>>the pinhole and alt-process lists.)
>>>
>>>--shannon
>>>
>> D-76 is not a particularly high contrast developer. You might have better
>>results with Kodak DK-50. Start at 1:1 dilution. Its a medium grain
>>developer, about like T-Max RS, that should make no difference for 8x10.
>> For higher densities you might have to go to T-Max 400, which is capable
>>of higher contrast and density than HP-5. Even with D-76 T-Max 400 will
>>reach log densities of 3.0.
>>----
>>Richard Knoppow
>>Los Angeles, CA, USA
>>dickburk@ix.netcom.com
>
>
>
>
>You might also try Kodak's D-19, a very energetic developer that will
>give you about as much contrast as you can get outside of a staining
>developer. Zoe Zimmerman, whose work was featured in a recent issue
>of View Camera, mentioned at the Large Format Conference in
>Albuquerque that she uses D-19 for negatives she intends to print in
>albumen, which requires a density range of 1.8 and above. I don't
>know if D-19 is still packaged by Kodak, but if not you can find the
>formula in a number of sources.
>
>However, my personal opinion is that to get any snap in your print
>with HP5+ from a really low-contrast scene you will be better off
>with either ABC+ or Pyroca-HD since the effective printing DR with
>these developers will be much greater than the actual DR read by a
>densitometer because of the actinic stain.
>
>Sandy King
>
>
>--
D-19 has a lot of bromide in it. It was originally intended as a
developer for
x-ray and special purpose films where high contrast but not extreme
contrast was desired. The bromide will reduce film speed a little.
Pyro is like a combination of a developer and an intensifier. The stain
image adds density exactly in proportion to the silver. If density is
measured using a blue filter densitometer readings will be more in line
with the printing density. Pyro negatives should look a little thin when
examined by eye.
The desired contrast depends on the printing method, of course.
From Shannon's post she wants a maximum density of around 2.0, this
should be obtainable with either HP-5 or Tri-X as well as T-Max
T-Max RS developer will also produce higher Dmax than D-76 and is
probably easier to find than either DK-50 or D-19. Its also a low fog
developer, useful for push processing. It also tends to produce straighter
characteristic curves than D-76. I should have mentioned it before.
Note that Tri-X _sheet_ film is a "long toe" film, whith a very long toe,
similar to the now discontinued Plus-X sheet film. This means that the
constrast increases with density all along the characteristic curve, there
is no real straight line portion. This is not a good choice if you want
fairly high shadow contrast. Shorter toe films, like T-Max are better. HP-5
is a medium toe film, better than Tri-X sheet film. Unlike Tri-X HP-5 seems
to have the same emulsion for both roll and sheet forms.
As far as T-Max blocking up, it really doesn't. It can get to very high
densities. The problem with it is that it needs more careful control of
development, otherwise highlight contrast may become too high. This is
different than blocking up since there is still printible detail in the
highlights, they just need burning in or masking. T-Max devleopers also
tend not to produce a shoulder on the characteristic. Actually, this sounds
exactly like what Shannon wants.
---- Richard Knoppow Los Angeles, CA, USA dickburk@ix.netcom.com
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