Stopbaths

STOPBATHS

All commercially available stopbaths are based on acetic acid or citric acid, some with an indicator added, to show the point at which the pH becomes too high for the bath to do its job. Indicating agents are expensive, adding to the cost of the product, and if you are producing a lot of work it may be worth getting in plain acetic acid in bulk, and a pack of pH papers. A few people suffer respiratory problems due to darkroom work, traceable to the stopbath. If this is the case, another weak organic acid which will work equally well, and has no vapour problem is citric acid. Tetenal supply several packings of odourless stop-bath.

TESTING STOPBATH

If not using an indicator stopbath, pH paper is a simple way of checking the stopbath is still active. Hydrion pH paper supplied in a dispenser with outer storage case, and large colour chart. Yields a sharp colour change for each pH unit. The range of the paper we stock is pH 1 through to 12.

Code	Product	Net	+VAT
28	Hydrion pH Paper	13.16	15.46

Ilford ILFOSTOP Available as 500 ml and 5 litre packs, and is now an odourless citric acid formulation without an indicator. Dilution of 1+19 for use.


Download ILFORD CHEMICAL SUNDRIES PDF

Code	Product	Net	+VAT
20 578	ILFOSTOP Stopbath 500ml	3.80	4.46

Kodak MAX-STOP 1 litre packing of 22% acetic acid, incorporating indicator, and giving a 1+15 working strength.

Code	Product	Net	+VAT
26 643	Kodak Max-Stop 1l.	3.24	3.81

Tetenal INDECIT

This is excellent value if you need an indicator stopbath. A 1 litre pack of approximately 70% acetic acid, incorporating indicator, used at 1+39.

Code	Product	Net	+VAT
24 367	Indicet Stopbath 1l.	7.99	9.39

Foma CITRO This is ....

Code	Product	Net	+VAT
54 707	Foma Citro Stopbath 250ml.	2.54	2.98

ACETIC ACID

The most economical route, but as the solution contains no indicator care should be taken to ensure that the bath does not become exhausted. Dilution is normally to about 3%

Code	Product	Net	+VAT
867 350	Agfa - 60% Acetic Acid, 5l.	10.00	11.75

CITRIC ACID

This mild acid is completely odourless in solution and can be used as a substitute for proprietary acetic acid stopbaths if the odour is irritating. Use at a rate of approximately 20g per litre of water.

Code	Product	Net	+VAT
20 539	Citric Acid 100g	1.55	1.82
97 971	Citric Acid 500g	6.25	7.34

Tetenal ODOURLESS STOPBATH

A prepared package of odourless stop, available in 250ml and 5 litres.

Code	Product	Net	+VAT
17 363	Tetenal Odourless Stopbath 1litre	9.00	10.58

Alternative Stopbaths Stocked

Code	Product	Net	+VAT
24 075	Fotospeed SB40 Indicator Stop 250ml	2.30	2.71
24 087	Fotospeed SB40 Indicator Stop 500ml	2.85	3.34
24 090	Fotospeed SB40 Indicator Stop 1l.	5.33	6.26
24 107	Fotospeed SB50 Indicator Stop 1l.	5.79	6.80
24 110 §	Fotospeed SB50 Indicator Stop 5l.	18.95	22.27