Film Processing and Formulae .....

Some Basic Film Processing Formulae (modified 13/01/2024)

Download Printable Summary of Formulae Download Raw Chemicals List with Suppliers

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

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 for developers is prepared by adding STPP at a rate of 1.5 g/L for tap water containing 250 ppm of hardness.
For other solutions, use the same quantity of EDTA with an optional addition of 0.2 g/L of Sodium hydroxide to return the pH to neutral. EDTA remains stable in photographic chemicals but unfortunately is not recommended for developers as it appears to be able to catalyse the unwanted effect of aerial oxidation due to trace ferrous ions during the development process.
(See "Photographic Processing Chemistry", L. F. A. Mason Focal Press, page 59).
Both Calgon and sodium tripolyphosphate (STPP) are unstable in alkaline developer solutions. After a few days or weeks, calcium deposits will appear as the phosphates are hydrolysed. Storage times with STPP softened developers is therefore limited and should be used without significant delay.
Also remember, if developers are to be diluted, pre-prepared softened water will have to be used.

Prepare developers as follows:

1. Add STPP first in the preparation of developers, at 40C, (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 micron bag filters.

1. Use either standard Ilford agitation, 10 seconds (4 inversions) at the start of every minute or, if specified, 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 or acetic acid stop bath, and again with plain water.
4. Fix with acid 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.

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:

Buffered Acetate Fixer Formula - to make 1000ml

Start with 750ml of warm water
Soften the water as above using EDTA 1.5 - 2g
Sodium Thiosulphate pentahydrate 250g
Sodium Sulphite anhydrous 15g
Acetic Acid 80% solution 25 mL
Sodium Acetate ( anhydrous) 25 g
Unused fixer pH = 4.7
Leave to stand for a while then filter out any white scum before use starting with a 10 micron bag filter.
followed by a 1 micron filter.