Skip to content
AnalogFixerDarkroom chemistry for black-and-white film
Browse sections

Section

Archival permanence

What properly fixed and washed means in measurable terms, which standards define it, and what the published limits actually apply to.

In this section

  • Print LE-100 no longer names 21 °C and 50 % RH

    Shows that ISO 18929:2003 defined life expectancy and the LE designation by dark storage at 21 °C and 50 % RH — the same ambient pair ISO 18901:2010 still prints for film — while the 2012 second edition of ISO 18929 replaces those figures with “conditions defined in the relevant standards,” naming ISO 18902 and ISO 18920 in a note, so an LE-100 label for a reflection print under the current print standard is no longer, on the face of the definition examined here, the same storage claim as LE-100 under the film standard or under the prior print edition.

  • Published sheets disagree on what selenium toner protects

    Shows that Kodak G-23 claims toning extends print-image life during display or storage against light, ultraviolet radiation, oxidizing gases and related hazards, and labels a Rapid Selenium Toner dilution for “print protection,” while Ilford Multigrade FB Classic puts selenium in an “optimum permanence” sequence framed for “archival storage” and then scopes toning to display protection from oxidising gases on the same sheet; that Ilford Chemical Sundries defines optimum permanence as residual-silver and thiosulfate minima and publishes a non-selenium path for that definition; that Kodak AJ-3 shortens the product claim to tone change and “prolonging print life”; and that ISO 18929’s LE-100 print criteria are dark-storage residual and physical limits that include toned prints in scope without requiring toning, exclude displayed prints, and deprecate “archival.”

  • Status A blue density is not one permanence ceiling

    Shows that three ISO permanence clauses examined here that all use Status A blue densitometry publish three different numeric ceilings for three different tests: ISO 18901:2010 Clause 6.5 caps residual silver compounds on film at a 0,02 Status A blue density increase; Clause 7.2 caps radiographic-film image-stability change after incubation at 0,05 Status A blue density units for LE-10, LE-100 and LE-500 alike; and ISO 18929:2012 Clause 6.3 caps print yellowing after incubation at 0,08 Status A blue density units on minimum-density areas — so a quoted Status A blue permanence number has to name which clause and material it came from.

  • Ilford Washaid is labeled eliminator and clearing agent

    Shows that Ilford’s December 2017 Chemical Sundries sheet introduces Washaid as a hypo-clearing agent and then describes the same product as a hypo-eliminator that removes thiosulfate by ion exchange — the mechanism ISO 18901 and ISO 18929 assign to permitted hypo-clearing baths, not to the oxidizing hypo-eliminating agents those standards prohibit — and that Kodak AJ-3 keeps the clearing-agent name while excluding RC papers for a short-wash reason that is not the permanence-section wording ISO 18929 uses for the same exclusion.

  • Washing to zero is not what the standards ask for

    Shows that the standard darkroom instruction — wash until the residual hypo test reads clean — is contradicted by every document that has ever put a number on it: the US federal specification for permanent microform required residual thiosulfate to be greater than zero, and both current ISO standards warn that very low concentrations make the silver image more susceptible to oxidative attack while noting the target may sit below the detection limit of the test itself. Also traces the federal ceiling for permanent microform from 0.007 g/m² in 1980 to 0.014 g/m² today, a doubling that happened by incorporation of a different standard and was never announced as a change.

  • Federal archival microfilm once allowed cellulose ester or polyester

    Shows that FIPS PUB 82 (1980), adopting NMA MS1-1980, classified archival silver-gelatin microfilm by reference to either the cellulose-ester archival film specification (ANSI PH1.28) or the polyester archival film specification (ANSI PH1.41), while current 36 CFR § 1238.14(b) requires polyester-based silver-gelatin film conforming to ISO 18901 for LE 500 film in all applications — matching ISO 18901’s rule that LE-500 applies only to polyester-base film and that cellulose-ester film tops out at LE-100 — a base-material change that arrived by standards incorporation rather than as an announced processing revision.

  • LE-100 residual thiosulfate is not one ceiling

    Shows that the residual-thiosulfate ceiling attached to LE-100 is not one number across the film and print standards examined here: ISO 18929:2012 sets a single 0,014 g/m² limit for fibre-base and RC prints that earn an LE rating of 100, while ISO 18901:2010 Table 2 sets film LE-100 at 0,050 g/m² for radiographic and “other” films and at 0,030 g/m² for microfilms — and the familiar 0,014 g/m² figure appears on that film table as the microfilm and other-films LE-500 cells (radiographic LE-500 is 0,020), so quoting 0,014 as “the LE-100 residual” collapses print LE-100 with film LE-500.

  • Residual silver is a density limit on film and a mass limit on prints

    Shows that residual silver is not one ISO limit across the film and print standards: ISO 18901:2010 Clause 6.5 caps residual silver compounds by a Status A blue density increase of 0,02 under a densitometric test, while ISO 18929:2012 Clause 6.2 caps residual silver concentration at 0,025 g/m² by atomic absorption — same everyday label, different property names, units, and methods — and that HARMAN / Ilford’s December 2017 Chemical Sundries sheet keeps “residual silver” as the qualitative “adequately fixed” half of optimum permanence without printing either figure.

  • Two Ilford sheets disagree on fibre-base wash time

    Shows that Ilford’s July 2010 Rapid Fixer sheet and October 2013 Multigrade FB Classic sheet publish different plain running-water wash times for fibre-base paper after Rapid Fixer 1+4 for one minute at the overlapping temperature of 20°C — sixty minutes versus thirty to forty-five — while both prescribe the same Washaid timings and 1+4 dilution under different temperature wording and framings, and that neither document explains why the plain-water figures differ.

  • Washaid’s final wash is five minutes and twenty on one page

    Shows that HARMAN / Ilford’s December 2017 Chemical Sundries sheet publishes two different final running-water wash times for the fibre-base Washaid path on the same page — twenty minutes in the processing-sequence table and five minutes in the Optimum permanence sequence — while that page’s selenium-toner sequence uses a thirty-minute final wash; that the July 2010 Rapid Fixer sheet and the October 2013 Multigrade FB Classic sheet match the five-minute final wash, not the twenty; and that Kodak AJ-3’s Hypo Clearing Agent wash reduction for double-weight paper is twenty minutes, matching the table rather than Ilford’s “optimum permanence” final-wash figure.