Amidol
chemical compound
Amidol is a colorless crystalline compound with the molecular structure C6H3(NH2)2OH. It is a dihydrogen chloride salt and is used as a photographic developer. It was introduced as a developing agent for photographic papers in 1892. It is unusual amongst developing agents as it works most effectively in slightly acid conditions rather than the strongly alkaline conditions required for most other developers. As amidol ages it changes color to a dark red-brown. Developing dishes and equipment used to prepare amidol solutions are also frequently stained brown, a stain that is very persistent.
Prints developed in amidol are typically a very warm brown-black color, but overdevelopment can quickly lead to chemical fogging.
Amidol's color change upon oxidation is used to advantage as a convenient colorimetric method for measuring the dissolved oxygen concentration in water supplies, rivers, etc.
Begin with the source’s own compact description: “Amidol” is chemical compound. The dossier treats that line as a proposition to test through Amidol, chemical and compound, not as a finished interpretation.
Why this record matters
The phrase “chemical compound” supplies a clear boundary for inquiry. It also exposes the unanswered questions: who defined that boundary, when it became stable and which sources sit outside it.
The date and method of observation matter as much as the stated conclusion, especially where classification or consensus has changed. The source revision retrieved here is dated Sep 20, 2026. The linked authority identifier is Q3297000. None of the 0 selected statements returned an explicit reference. The first chronological checks are 1892.
A general summary may omit uncertainty, sample limits or methodological disagreement that is explicit in the technical record. The lead is largely declarative, so disagreement and counter-evidence require a deliberate search beyond the opening account. Authority statements aid reconciliation but still require their own references, qualifiers and ranks to be checked.
How to read it
Check terminology, classification and the date of the cited evidence. Scientific names and technical consensus can change while older records retain historical value.
- Current terminology
- Classification context
- Finding cited technical literature
Primary datasets, specimen catalogues, standards bodies and the most recent peer-reviewed literature.
Three-step research path
- Establish the record: confirm the title “Amidol”, its source revision and the description used here.
- Expand the search: follow Amidol primary sources, Amidol archive and Amidol research across catalogues and specialist indexes.
- Test the account: compare the strongest cited source with the responsible institution’s current record and note any disagreement.
Questions for further research
- Which source most directly establishes the central claim about “Amidol”?
- Which observation, specimen, dataset or publication supports the account?
- Is the terminology current, historical or disputed?
Search terms from this dossier
This entry incorporates text from “Amidol” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.