b-w technik

Low Cost Darkroom Techniques


Film Processing and Formulae .....

Some Basic Developer Formulae (modified 24/7/16)

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Name Metol Phenidone Hydroquinone Sodium Sulphite Sodium Carbonate Potassium Bromide Sodium Chloride Borax Boric Acid EDTA Sodium Hydroxide
ID11 2 - 5 100 - - - 2 - 1.5 0.2
ID11b 2 - 5 100 - - - 8 3.6 1.5 0.2
ID68 (see note 2) - 0.13 5 85 - 1 - 7 2 1.5 0.2
PF (see note 3) 5 - - 100 - - 30 - - 1.5 0.2
Beutler A 10* - - 50*           1.5 0.2
Beutler B - - - - 50* - - - - 1.5 0.2

Notes

1). Beutler : mix 100ml A + 100ml B + 800ml water
*** Original Beutler has 5g of Metol, 25g sodium sulphite and 25g sodium carbonate ***
2). ID68 is a PQ buffered version of ID11 perhaps similar to Ilford Microphen
3). PF is similar to Ilford Perceptol
4). EDTA - disodium salt, dihydrate, see below
5). Sodium Sulphite is anhydrous.
6). All formulae are to make 1000ml.

ID11b Buffered Version

NOTE this has NOT been tested as a substitute for ID11 stock. It is intended to be used 1:1 where it is closer to ID11 stock than ID11 1:1.
See the HP5+ data for a comparison

Softening Water

Softened water is prepared by adding EDTA at a rate of 1.5 g/L for tap water containing 300 ppm of calcium as carbonate.
Add 0.2 g/L of Sodium hydroxide to return the pH to neutral.
Both Calgon and sodium tripolyphosphate (STPP) appear to be unstable in alkaline solutions. In developers, they will work initially but after a few days or weeks, unwanted deposits will begin to form as the phosphates are hydrolysed.
If the developers are to be diluted, pre-prepared softened water will have to be used.

Prepare developers as follows:

1. Use tap water when EDTA is included in the formulae for developers, 40-50C, (120F). To make 1000ml, start with 750 ml.
2. Add a quarter teaspoon of sodium sulphite first to minimise oxidation of the developing agents.
3. Mix in the order of the table e.g. Metol / Phenidone / Hydroquinone first.
4. Finally, make up to 1000ml, filter and store.

Developing Procedure used:

Filter all solutions immediately before use. I use 1-10 micron bag filters.

1. Use either standard Ilford agitation, 10 seconds (4 inversions) at the start of every minute or continuous agitation which is 2 inversions, taking 5 seconds, followed by 5 seconds dwell time.
2. Temperatures controlled to within the range 19.7C to 20.3C.
3. Stop bath, wash once with 0.3% sodium metabisulphite solution, or similar citric acid stop, and again with plain water.
4. Fix with alkaline/ neutral fixer (see formula below) for 7 - 10 minutes.
5. Wash for 15 minutes in running tapwater at 20C.
6. Wash or spray with distilled water to remove tap water to minimise drying marks. Alternatively, spray then wipe with a damp microfibre drying cloth.

Despite all the filtering above, an examination of the developer after use shows significant levels of dust and small fibres. This is clearly attaching itself to the tank, spiral holder and film when it is being handled during the loading stage. The use of low cost semi disposable, anti static laboratory coats is being tried to see if this can be improved.

Alkaline Fixer and Stop Bath

Maintaining low pH solutions throughout the process appears to have some advantages such as faster washing times and much better preservation of fixer solutions. Initially when processing PanF, small white bubbles appeared in the emulsion. The reason for this was difficult to determine. At that time, acetic acid stop baths were being used thus it is possible that in hard water, carbon dioxide could be produced in the emulsion. Ilford could not offer a reason for the problem so it was decided to use weakly acidic or neutral buffered one-shot stop baths. The fixer formula used is as follows:

Modified TF-2 Alkaline Fixer Formula - to make 1000ml

Start with 750ml of warm water
Soften the water as above.
Sodium Thiosulphate pentahydrate 250g
Sodium Sulphite anhydrous 15g
Disodium phosphate 15g
Potassium dihydrogen phosphate 6g
Ammonium chloride anh. 40g make up to 1000ml, pH 7.6

Filter out any white scum before use starting with a crude cotton wool filter or 50 micron bag filter followed by 10 micron filter.