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Pure Silver

The full curriculum

The course runs from the eighteenth-century discovery that silver salts darken in light to a portfolio of prints you have made with chemistry you understand. This page lists all of it. Parts are numbered and kept in order; each carries its level; each page carries its kind, its safety level where it has one, and an estimate of the time it takes.

The four levels

Section titled “The four levels”

Level 1 — Foundation

3 parts29 pages24 h

How light and silver met: the history, the laboratory discipline and the chemistry needed to understand everything that follows.

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1. Before Photography: When Chemistry Discovered Light2. The Photographic Chemistry Laboratory3. Chemistry Foundations for Photographers

Level 2 — Practitioner

10 parts79 pages135 h

Make a camera, expose film, formulate and understand the processing chain, and print with intent.

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4. Silver and Light6. Build a Pinhole Camera7. The Art of Pinhole Photography8. Film Developer Chemistry10. Stop Baths11. Fixing Chemistry12. Washing, Permanence and Silver Recovery13. Sensitometry: Measuring the Response of Silver to Light18. Printing Chemistry19. Fine Printing

Level 3 — Advanced

13 parts98 pages199 h

Manufacture emulsions, measure the process with instruments you build, and control the darkroom quantitatively.

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5. Photographic Emulsions9. The Developer Laboratory14. Build a Sensitometer15. Build a Densitometer16. Build the Darkroom17. Build the Pure Silver Timer20. Toning Chemistry21. Cyanotype: Photography in Prussian Blue22. Salted Paper: The First Silver Print23. Albumen Printing24. Iron-Silver Processes: Van Dyke Brown and Kallitype26. Historical Processes We Study But Do Not Casually Reproduce28. Failure Analysis

Level 4 — Specialist

3 parts24 pages76 h

Alternative and historical processes, experimental chemistry, failure analysis and the portfolio that demonstrates the whole chain.

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25. Platinum and Palladium27. Experimental Photographic ChemistryThe Pure Silver Portfolio

Page kinds

Section titled “Page kinds”
Kind Meaning
Overview The first page of a part
Lesson Explanation, connected to what you will see on film or paper
Lab A practical procedure following the course’s lab template
Build A construction project
Experiment A controlled comparison with one changed variable
Break/fix A diagnostic scenario
Assignment A photographic task
Capstone A component of the final portfolio

The whole course

Section titled “The whole course”

Part 1Before Photography: When Chemistry Discovered LightLevel 1 · Foundation11.7 h

Camera obscura optics, the eighteenth-century discovery that silver salts darken in light, the failure to fix images, and the 1816-1846 processes (heliography, daguerreotype, photogenic drawing and calotype, hypo fixing, cyanotype) that solved sensitivity, permanence and reproducibility, with three chemistry-free practical pieces: a camera obscura, an unfixed silver photogram and a permanent cyanotype photogram.

Part 2The Photographic Chemistry LaboratoryLevel 1 · Foundation6.0 h

Laboratory discipline before any chemistry is mixed: wet and dry areas, ventilation and contamination control; hazard, risk, PPE, eyewash, spills and emergency response; safety data sheets, GHS, CAS numbers and labelling; storage, incompatibilities and secondary containment; the specific rules silver nitrate imposes; waste streams and silver-bearing waste; measurement of mass, volume, temperature and density with honest uncertainty; and the concentration arithmetic (percent w/v, w/w and v/v, molarity, stock and working solutions, dilution ratios, C1V1 = C2V2) that every formula in the rest of the course assumes, closing with a commissioning lab in which the student checks their instruments, mixes and labels a stock solution and opens the lab notebook.

Part 3Chemistry Foundations for PhotographersLevel 1 · Foundation6.3 h

Chemistry from first principles for a reader with no chemistry beyond school, built so that every concept lands on a photographic consequence: atoms, ions, bonding and how to read a formula; solutions, solubility, equilibrium and precipitation; acids, bases, pH and buffers, with a laboratory session calibrating a pH meter and measuring real photographic baths; oxidation, reduction and electron transfer, and the aerial oxidation that kills chemistry in a half-empty bottle; reaction rates, temperature and catalysts; complex formation and the ligand chemistry that makes fixing possible; and diffusion, swelling and transport through gelatin, which explains agitation, edge effects, washing and reticulation.

Part 4Silver and LightLevel 2 · Practitioner10.3 h

Silver, the silver ion and the three photographic halides; the crystal lattice and its defects; how a photon becomes a trapped electron, a silver atom and a developable latent-image cluster; why development amplifies it into filamentary silver; what crystal size, shape and dye sensitisation do to speed, grain, resolution and colour response; one bench experiment on the halides and one darkroom session that measures the latent image on ordinary paper.

Part 5Photographic EmulsionsLevel 3 · Advanced30.5 h

Gelatin, precipitation, ripening, washing, digestion, sensitisation, coating, drying, hardening, defects and storage, taught through a coating station build, a commercial-emulsion practice run, and five progressively harder emulsions the student makes and tests: silver chloride contact paper, chlorobromide paper, bromide enlarging paper, glass dry plates and a lantern slide, and a double-jet iodobromide emulsion the student designs, ending in a hand-coated portfolio print.

Part 6Build a Pinhole CameraLevel 2 · Practitioner21.8 h

Pinhole optics from straight-line geometry through diffraction to a defensible choice of hole size and exposure, then a modular camera with interchangeable pinholes, backs and focal distances that is tested for leaks and flare, commissioned with three exposure series on paper negatives, used for flat-versus-curved-plane and multiple-pinhole experiments, and diagnosed when it goes wrong.

Part 7The Art of Pinhole PhotographyLevel 2 · Practitioner24.8 h

Previsualisation without a viewfinder and the pinhole's own rendering of space, time and tone, applied through seven logged assignments covering still life, architecture, movement, portraiture, landscape with filters, night and solargraphy, and the curved or multiple pinhole, closed by a portfolio review that turns the exposure records into data.

Part 8Film Developer ChemistryLevel 2 · Practitioner17.8 h

The reduction of exposed silver halide to metallic silver, the ingredients that make it selective, and how their proportions determine grain, speed, contrast and edge behaviour.

Part 9The Developer LaboratoryLevel 3 · Advanced25.3 h

Controlled single-variable experiments on developer pH, bromide, sulfite, dilution, agitation and developing agent, evaluated semi-quantitatively with step-wedge samples and archived for measurement in Part XXVII.

Part 10Stop BathsLevel 2 · Practitioner3.6 h

How an acid bath halts development in seconds, what carryover and buffering do to its capacity, and how acetic, citric, indicator and water-rinse alternatives compare.

Part 11Fixing ChemistryLevel 2 · Practitioner10.8 h

Thiosulfate complexation of unexposed silver halide, the kinetics and capacity of sodium and ammonium fixers, acid, hardening, neutral and alkaline formulations, and the tests that show when fixing is complete.

Part 12Washing, Permanence and Silver RecoveryLevel 2 · Practitioner11.0 h

Diffusion-driven removal of thiosulfate and silver complexes, the deterioration chemistry they cause if left behind, the tests that prove a wash, and responsible handling of silver-bearing waste.

Part 13Sensitometry: Measuring the Response of Silver to LightLevel 2 · Practitioner11.0 h

Exposure and density as logarithmic quantities, the Hurter and Driffield characteristic curve and its parameters (gamma, contrast index, average gradient, speed), paper curves and ISO(R), tone reproduction from subject to print, and the student's first measured curve from a step-wedge exposure series.

Part 14Build a SensitometerLevel 3 · Advanced13.3 h

Low-voltage electronics for the darkroom builder, the design of an intensity-scale LED sensitometer with a calibrated step wedge and microcontroller timing, its construction in two builds, a calibration experiment with an honest error budget, and its first real use as a process-control instrument.

Part 15Build a DensitometerLevel 3 · Advanced16.8 h

The geometry and spectral conditions that define a density reading, photodiodes and analogue-to-digital conversion, a transmission densitometer built as an optical head and an electronics module, its calibration against a reference wedge with an uncertainty statement, a break-fix diagnosis page, and the first full film-and-developer characterisation using both instruments.

Part 16Build the DarkroomLevel 3 · Advanced25.5 h

Making a room dark and proving it, designing and building an LED safelight whose safe working time is measured rather than assumed, a contact printing frame with a uniform light box, an interlocked UVA exposure unit for the alternative processes, and an LED enlarger head with the alignment and uniformity tests that any enlarger must pass.

Part 17Build the Pure Silver TimerLevel 3 · Advanced17.0 h

Why printing exposure is counted in stops rather than seconds, how a low-voltage microcontroller switches the lamps this course builds without mains entering the instrument at any point, and the construction, firmware, calibration and fault diagnosis of a darkroom timer with tenth-of-a-second resolution, an audible metronome, a foot switch and f-stop and repeat modes.

Part 18Printing ChemistryLevel 2 · Practitioner9.5 h

What a sheet of printing paper is made of, how its emulsion decides image tone and contrast, what a print developer does that a film developer does not, and where the black, the white and the dry-down of a finished print actually come from.

Part 19Fine PrintingLevel 2 · Practitioner14.5 h

Taking one negative from a proof to a finished, mounted print: anchoring the exposure, choosing and splitting the contrast, controlling tones locally with the hands, developing and finishing consistently, and judging the result by a method rather than by mood.

Part 20Toning ChemistryLevel 3 · Advanced13.3 h

What a toner does to a silver image at the level of the particle: converting it to a sulfide or selenide, plating it with gold, or building a coloured compound around it, and what each conversion costs and buys in colour, density and lifetime.

Part 21Cyanotype: Photography in Prussian BlueLevel 3 · Advanced15.2 h

The iron process that needs no silver: how light reduces an iron(III) salt, how the iron(II) it makes builds Prussian blue with hexacyanoferrate, and how that chemistry is turned into a coated, exposed, washed and toned print on paper and cloth.

Part 22Salted Paper: The First Silver PrintLevel 3 · Advanced9.2 h

The oldest surviving photographic printing process, in which silver chloride is precipitated inside the fibres of a sheet of writing paper and darkened by light alone, without a developer, and made permanent by toning, fixing and washing.

Part 23Albumen PrintingLevel 3 · Advanced7.6 h

The process that put a protein binder between the silver and the paper: how egg white is salted, whipped, coated and sensitised, why that thin layer changes density, colour and gloss so completely, and why the resulting print is the most numerous photographic object of the nineteenth century.

Part 24Iron-Silver Processes: Van Dyke Brown and KallitypeLevel 3 · Advanced11.8 h

The processes in which light reduces iron(III) to iron(II) and the iron(II) then reduces silver to metal: how a single sensitiser combines the chemistry of Part XXI with the silver of Part XXII, and why the resulting prints are either superb or short-lived depending almost entirely on how they are cleared.

Part 25Platinum and PalladiumLevel 4 · Specialist17.0 h

The most expensive and most permanent of the hand-coated processes: how iron(II) made by light reduces a platinum or palladium salt to metal in the fibres of the paper, why the resulting image outlives its support, and whether that is worth what it costs.

Part 26Historical Processes We Study But Do Not Casually ReproduceLevel 3 · Advanced5.8 h

The chemistry, workflow, image properties and significance of the daguerreotype, wet-plate collodion, the cyanide darkroom, the heavy-metal intensifiers and the dichromated colloids, taught as history and mechanism with no procedure given for any of them.

Part 27Experimental Photographic ChemistryLevel 4 · Specialist17.0 h

The second pass through development chemistry, run with the sensitometer and densitometer the student built, in which the archived Part IX strips and a small number of new runs turn every claim about pH, sulfite, bromide, dilution, time, temperature, agitation, exhaustion and film speed into a measured curve with an uncertainty attached.

Part 28Failure AnalysisLevel 3 · Advanced8.3 h

The diagnostic half of everything the course has taught: every common defect of the negative and the print traced to the chemical or physical event that produced it, the evidence that identifies it, and the change that prevents it.

CapstoneThe Pure Silver PortfolioLevel 4 · Specialist41.5 h

The final project: the course's scattered assignments pulled into one progression, then a body of six to ten finished works made with an instrument the student built, chemistry the student formulated and documented, a process the student measured, prints the student toned and cross-printed in an alternative process, and a chemistry report that accounts for every stage from photon capture to the finished print.