Disclaimer

⚠Read this before your first purchase

This course is educational material about hazardous chemistry, electricity and light. It is not professional advice, not a safety data sheet, not a regulatory document and not a substitute for training. It cannot see your room, your ventilation, your local rules, the product in your hands or the person next to you. The judgement about whether a procedure is safe for you, where you are, with what you have, remains yours.

What the course does claim

Every formula, hazard statement, historical date and process description in the course was checked against a named source on a stated date, and that source is listed at the foot of the page making the claim and in the sources index. Where the course could not verify something it says so, or leaves it out. Where history is contested, it says that too. That is the standard the course holds itself to, and the content-error issue template is the way to hold it to that standard when it falls short.

Chemicals

Photographic chemistry uses substances that are corrosive, toxic, sensitising or harmful to aquatic life, sometimes in small quantities and sometimes in large ones. The course classifies every practical page from Level A (a standard home darkroom with gloves, eye protection and ventilation) to Level D (historical study only, with no home procedure given), and the classification rubric states the criteria. That classification is a hazard assessment of the procedure as written. It is not a guarantee of safety, and it does not transfer to a variation you make.

The safety data sheet for the specific product you buy is the authority on its hazards, not this course. Suppliers reformulate products, classifications are revised, and the same common name can cover different grades and hydrates with different properties. Obtain the current SDS before you open the container, and follow it where it disagrees with anything here.

The course names incompatibilities it knows about. It does not know all of them. Never mix solutions the course does not tell you to mix, never add water to concentrated acid, and never combine a chemical with anything containing hypochlorite bleach.

Waste and the environment

Silver-bearing solutions, spent developers and many toners must not go down a domestic drain in most jurisdictions, and the rules differ between countries, regions and even water companies. The course teaches the chemistry of silver recovery and the general principles of responsible waste handling. It does not tell you what is legal where you live, because it cannot. Find out, and comply.

Equipment and electricity

The course describes building a pinhole camera, a safelight, a contact printer, a UV exposure unit, an enlarger, a timer, a sensitometer and a densitometer. Where a build touches mains voltage, the course prefers certified, enclosed components and low-voltage designs and says so on the page, but you are building the device, not the course. Electrical work is regulated in most countries; a device you build for yourself is your responsibility, and one you sell or give away may be subject to product-safety law. Ultraviolet sources can injure eyes and skin; the course describes enclosures and interlocks, and expects you to use them.

Historical processes

Some processes of great historical importance used mercury vapour, cyanide, uranium, cadmium or chromium(VI) compounds. The course teaches their chemistry, their history and why they mattered, and classifies them Level D: it does not give a procedure, and it asks you not to attempt one from other sources without the facilities and supervision those substances require. Curiosity about the daguerreotype is a fine thing. Mercury poisoning is not.

Measurement, prices and results

Densities, exposure times, capacities, shelf lives and other figures quoted in the course come from the cited sources or from the course’s own worked examples, which are marked as such. Your water, your temperature control, your film batch and your agitation will differ. The course teaches you to measure your own process precisely so that you do not have to trust anyone else’s numbers, including its own.

Prices in the laboratory planner are estimates, dated, in a stated currency and region. They will be wrong by the time you read them. Treat them as a way to plan, not as quotes.

Not affiliated

The course names commercial products (Kodak, Ilford, Foma and others) because their published technical documents are among the best sources available. It is not affiliated with, endorsed by or connected to any manufacturer or supplier, and product names are the trademarks of their owners.

No warranty

The content is provided as is, under the licences stated in the repository, without warranty of any kind. To the fullest extent permitted by law the authors accept no liability for any loss, injury or damage arising from its use. If that sentence seems cold after everything above, the warmer version is this: the course was written with great care by people who want you to make photographs for the rest of your life, with all your fingers and both your eyes.