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Developer and fixer chemistry

Ilford’s manual 1+9 is a paper clause, not a film path

Shows that Ilford Rapid Fixer (July 2010; same structure in August 2002) and Hypam (August 2002) each publish a categorical film dilution sentence — “for all film fixing applications … diluted 1+4” — and place the optional 1+9 wording only inside the following paper-machine paragraph (“for manual fixing applications it can be diluted either 1+4 or 1+9”); that the fixing- time, capacity and replenishment tables populate film only at 1+4 while paper rows carry both dilutions with doubled paper times at 1+9 and the same published capacity per litre of working strength; and that Multigrade FB Classic (October 2013) independently cites Rapid Fixer or Hypam at 1+4 for one minute, not the 1+9 paper path.

Published by AnalogFixer ·

Ilford’s ammonium-thiosulphate rapid fixers are often summarised as “use 1+4, or 1+9 for economy.” That compression erases a paragraph boundary the sheets themselves draw. On Rapid Fixer and on Hypam, film is told to use 1+4. The sentence that offers 1+9 sits in the paper-mixing paragraph. The tables then fill film numbers only at 1+4 and paper numbers at both dilutions.

This is a document comparison of dated Ilford sheets. It is not a mixing, handling, reuse or disposal guide, and it does not treat any sheet as current beyond the revisions named below.

Two sentences, not one house dilution

On Ilford Rapid Fixer, July 2010, the mixing instructions read in this order:

  1. “For all film fixing applications ILFORD RAPID FIXER is diluted 1+4 with water.”
  2. “For use as a fixer in paper processing machines ILFORD RAPID FIXER is diluted 1+4 with water but for manual fixing applications it can be diluted either 1+4 or 1+9.”

The August 2002 Rapid Fixer revision (footer 02034.www August 2002) carries the same pair in the same order. Hypam, August 2002, uses the same film sentence for Hypam, then the same paper-machine / manual 1+4-or-1+9 sentence, and adds that Hypam Hardener is not recommended for any paper fixing application.

Clause What it authorises on these sheets What it does not say
Film sentence 1+4 for all film fixing applications No film 1+9 option
Paper-machine sentence Machine paper at 1+4; manual paper fixing at 1+4 or 1+9 Not a free-floating “manual anything” permission that overrides the film sentence

Reading “manual fixing applications … 1+4 or 1+9” as a film rule lifts the phrase out of the paper paragraph that contains it. The sheets already have a film rule one sentence earlier.

Fork showing 1+9 dilution as paper-only clause separate from film fixing path.

The tables agree with the paragraph split

Rapid Fixer’s July 2010 fixing-times table (average minimum times at 20°C / 68°F, fresh fixer, manual processing) lists:

Material Dilution Time (minutes)
General purpose film 1+4 2–5
RC paper 1+4 ½
RC paper 1+9 1
FB paper 1+4 1
FB paper 1+9 2

There is no general-purpose-film row at 1+9. Hypam’s August 2002 table has the same dilution pattern for the non-hardener column (and adds a with-hardener film column that is outside this article’s subject).

The capacity table without replenishment follows the same split. General-purpose film is listed at 1+4 only: 24×135–36 rolls per litre of working-strength fixer. RC paper lists 1+4 and 1+9 against one capacity figure — 80 sheets of 20.3×25.4 cm (8×10 in), or 4 m² — per litre of working strength. FB paper lists both dilutions against 40 sheets (2 m²) per litre. Hypam’s August 2002 capacity block matches that pattern.

Replenishment rates on Rapid Fixer July 2010 again give film only at 1+4 (45 ml working-strength fixer per 135–36). RC and FB paper rows show 1+4 and 1+9 against the same published replenishment volumes per area (250 ml/m² RC; 500 ml/m² FB).

So the optional 1+9 path is not an undocumented folklore dilution. It is a published paper path with published times. What the sheets examined here do not supply is a parallel film time, film capacity or film replenishment figure at 1+9.

Physical data for 1+9 is not a film process matrix

Both Rapid Fixer revisions print a pH / specific-gravity table for fresh working strength at 20°C that includes 1+4 and 1+9 (Rapid Fixer July 2010: 1+4 SG 1.070–1.080; 1+9 SG 1.030–1.040; pH 5.0–5.5 for both). Hypam’s August 2002 sheet likewise lists both dilutions in its pH/SG block. Those rows establish that 1+9 is a defined working strength on the sheet. They do not populate the missing film fixing-time or film-capacity cells.

The Rapid Fixer July 2010 availability note is consistent with the 1+4 film arithmetic already on the capacity table: a 5 litre bottle of concentrate is said to make enough working-strength fixer to fix 600×135–36 films, or 2000 8×10 RC prints, or 1000 8×10 FB prints. At 1+4, five litres of concentrate make twenty-five litres of working strength; 25 × 24 rolls/L = 600, 25 × 80 RC sheets/L = 2000, and 25 × 40 FB sheets/L = 1000. That bottle figure is a 1+4 working-volume calculation. It is not evidence that a 1+9 film path is tabulated elsewhere on the same sheet.

What the paper sheet cites

Multigrade FB Classic, October 2013, is a fibre-base paper document. Its processing summary and its optimum-permanence sequence both name ILFORD Rapid Fixer or Hypam at 1+4 for one minute at 18–24°C (64–75°F). That matches the fixer sheets’ FB paper row at 1+4. It does not cite the fixer sheets’ FB 1+9 / two-minute path.

That is useful as an independent paper-side citation of the 1+4 path. It is not a film instruction, and it is not a claim that the 1+9 paper path on the fixer sheets is invalid — only that this paper sheet does not use it.

What this does not establish

These sheets do not rank 1+4 against 1+9 for speed, capacity economy or permanence. They do not supply a film clearing-time or fixing-time figure at 1+9, so none is invented here. They do not say what an unopened later revision might publish. The information gain is narrower and documentary: on the Rapid Fixer and Hypam sheets examined here, “manual … 1+4 or 1+9” is a paper-clause alternative to machine-paper 1+4, sitting beside a separate film sentence that specifies 1+4 only, and the process tables follow that split. Kodak’s Rapid Fixer dilution fork is a cross-brand counterpart; see AJ-3 names Rapid Fixer film 1:3 and paper 1:7 — E-103CF’s Rapid row does not. The capacity table’s forty-sheet headline is the commercial silver threshold, not an archival headroom figure; see What fixer exhaustion actually means.

References