The following developer formula was proposed by G.W. Crawley after research into the design of acutance developers. FX-1 is fundamentally a variation of the Beutler formula claiming better contrast control, together with a mechanism to enhance "adjacency" effects; these are also enhanced by the lower concentration of the dev. agent. FX-1 High Accutance Developer Formula (Source : BJP Annual 1984) Speed Increase 1 Stop (Test!) Working Solution Metol 0.5 g Sodium Sulphite anhydrous 5.0 g Sodium Carbonate anhydrous 2.5 g Potassium Iodide 0.001% solution 5.0 ml Water to 1 litre Use once and discard. Do not use Calgon etc. Concentrated Stock Solutions Solution A Metol 5.0 g Sodium Sulphite anhydrous 50.0 g Potassium Iodide 0.001% 50.0 ml Water to 1 litre Solution B Sodium Carbonate anhydrous 25.0 g Water to 1 litre Making Up A Use water boiled for just 3 mins then cooled to about 30ºC. Dissolve a pinch of the weighed sulphite before the Metol. Filter and bottle This solution will keep for a year unopened or until discolouration begins - a light tint can be ignored. If 50 ml of the water is replaced by isopropyl alcohol, keeping qualities are improved and precipitation in extreme cold weather avoided. (See FX-2, Making up A, for general observations on making up concentrated liquid developers.) Amber glass bottles are preferable to plastic ones. B Dissolve in water prepared as for A. The 0.001% solution of Potassium Iodide can be obtained by dissolving 1 g in 1 litre of water; if 100 ml of that solution is diluted to 1 litre; then 100 ml of this solution to 1 litre this will give 0.001% solution. This keeps for two years at least. Working Solution Use once and discard. 1 part A : 1 part B : 8 parts Water. Mix well for 2 mins. Agitation 4 inversions each minute in small tanks up to 300 ml capacity, 6-8 in larger ones. (See also notes for FX-2.) General Notes FX-1 demands first-class lenses, precise exposure and no camera movement; also first class enlarger lenses. Highest resolution and definition will be obtained on Kodak Panatomic-X (Possilbly Ilford Pan F as well). Development Times (these may need adjustment - so test!) Agfapan 25 (35mm) 12 mins Agfapan 25 (120) 13 mins Agfapan 100 (35mm) 13 mins Agfapan 100 (120) 14 mins Ilford Pan F (35mm) 12 mins Ilford Pan F (120) 14 mins Ilford FP4 (35mm) 13 mins Ilford FP4 (120) 14 mins Kodak Pan-X (35mm) 13 mins Kodak Pan-X (120) 15 mins Kodak Plus-X Pan (35mm) 11 mins Kodak Plus-X Pan Pro 12 mins Kodak Verichrome-Pan 14 mins