[rollei_list] Re: JOBO development tips
- From: John Wild <JWild@xxxxxxxxxxxxxxxxxxxxxx>
- To: "rollei_list@xxxxxxxxxxxxx" <rollei_list@xxxxxxxxxxxxx>
- Date: Tue, 17 Dec 2013 11:28:52 +0000
Thor,
The way I determined the best processing procedure for my
film/exposure/developer combination was to follow a test that I found in a
book - it is quite long winded though...
Chose a subject with with whites having light shadows - a crumpled white
sheet or coarse knitted jumper, blacks having slight brighter areas - a
crumpled black cloth or coarse jumper and a range of mid tone - a grey
crumpled chequered shirt or jumper. I arranged these on the back of a garden
bench against a north facing brick wall on a sunny day - even overall
lighting.
I took three rolls of FP4 exposing a number frames of the same subject - not
necessary to use full roll - at each of EV, EV+1/2 EV+1, EV-1/2 and EV-1.
These lengths are then developed at standard time, pulled 1 stop and pushed
1 stop - you can go 2 stops if you wish.
You then inspect the negatives. The one(s) that give the best detail
rendition in both highlights and shadows will probably be your best
combination. Closer inspection of the full tonal range, grain size etc. will
help confirm your decision. By this method, you will also establish the best
processing time for over/under exposed film.
You can then repeat using other developer/exposure/development combinations
if you have nothing better to do ;-)
You will now be able to establish the combination of film, developer and ISO
for a particular film that gives the most pleasing results to you.
Technically, this should be carried out for each camera that you use -
shutter speeds may vary across the range affecting actual exposure. Also for
each type of film that you use.
If you are really fanatical, this should be repeated for each new batch of
film and or developer - akin to reloading ammunition.
My best combination doing this test only once was to use FP4 at ISO 80 (+1/3
stop) developed for recommended time in Ilfosol S - the developer that I
used at the time.
John
On 17/12/2013 07:29, "Thor Legvold" <tlegvold@xxxxxx> wrote:
> Ok,
>
> let me ask in a different way.
>
> How do I know if my negatives are over or under processed?
>
> I had taken 10 frames of a grey wall, just to check exposure (loosely
> following the zone methodology). Since I didn¹t focus carefully, nor were
> there any clear features on the wall, the test roll didn¹t tell me a whole
> lot.
>
> I did get 10 frames of differing density and two of the clear base, but can¹t
> be sure if the actual eposure, acutance and all the rest is appropriate.
>
> I¹m sure there must be a standard way to test this to find correct development
> times, right?
>
> Thanks,
> Thor
>
> On 17. des. 2013, at 01:06, Richard Knoppow <dickburk@xxxxxxxxxxxxx> wrote:
>
>>
>> ----- Original Message ----- From: "CarlosMFreaza" <cmfreaza@xxxxxxxxx>
>> To: <rollei_list@xxxxxxxxxxxxx>
>> Sent: Monday, December 16, 2013 8:17 AM
>> Subject: [rollei_list] Re: JOBO development tips
>>
>>
>> Thor:
>> I couldn't share my experience with you because I do manual
>> B&W film processing and never used an ATL 1500 nor prewash;anyway
>> developing times have to do with the negative contrast, I think you
>> need to find the best neg contrast for your purposes, f.e. print via
>> condenser (flatter negatives) or diffuser enlargers ( higher
>> contrast); it looks like a contrast for a diffuser enlarger is better
>> to scan negs for digital prints. BTW, variable contrast papers and
>> their filters help very much to compensate the negative features and
>> the differences Condenser vs Diffuser enlargers are not so
>> significant.
>>
>> Carlos
>>
>> The presoak affects the take up time for the developer so it has some
>> effect on total development time for a given contrast. The effect depends on
>> everything, film, temperature, developer, and must be determined by
>> experiment. Kodak used to recommend a pre-soak for processing sheet film by
>> hand to prevent the sheets from sticking together when first introduced to
>> the developer. I think JOBO recommends a pre-soak to slow the penetration of
>> the developer when it is poured into the tank so as to eliminate streaks due
>> to uneven development.
>> To add to what Carlos says above, Kodak philosophy was to standardize
>> development contrast based on the expected type of printer with an aim gamma
>> to match "normal" grade paper and then chosing contrast grade to correct as
>> necessary. This is as opposed to zone system processing where development is
>> adjusted to obtain a fixed negative contrast based on the scene contrast,
>> again so that all print on "normal" grade paper. The problem is that the
>> reproduced contrast of a scene may be considerably distorted from the
>> original contrast even though the entire range of brightness will be
>> reproduced as shades of gray. the Kodak method gives you essentially 1 to 1
>> brightness reproduction for some selected range of scene brightness. The eye
>> likes to have mid-gray tones reproduced 1:1 even if shadows and highlights
>> are compressed or clipped, otherwise the scene may look grayed out or overly
>> contrasty.
>> Development charts vary with manufacturer: Kodak charts used to be based
>> on suitable contrast index for diffusion printing sources, about one paper
>> grade more contrasty than ideal for a typical semi-diffusing condenser source
>> while Ilford uses a compromise value. In any case, as Carlos points out,
>> with variable contrast paper this is of little significance since the print
>> contrast can be adjusted for best visual effect from any reasonable negative.
>>
>>
>> --
>> Richard Knoppow
>> Los Angeles
>> WB6KBL
>> dickburk@xxxxxxxxxxxxx
>>
>>
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