Fuming doesn't add colour to wood. Ammonia vapour reacts with the tannin already in it, and the colour forms inside the fibre. That single fact governs everything else: the result can't be sanded, glue squeeze-out leaves a permanent light ghost, and the surface you prepared before the tent ran is the surface the colour reveals.

Most of what goes wrong with fuming is decided before the enclosure is sealed. Household ammonia is too weak to produce a real result. Boards from different logs fume to different shades. Brass hardware left in the tent corrodes. Kiln-dried stock straight off a hot rack fumes weakly and patchily. None of it is visible until the piece comes out, and by then none of it is fixable.

This guide covers the whole process in six lessons:

Chemistry, Species & Sourcing — what tannin is and where it sits in the tree, why the same species fumes differently board to board, which woods respond and which don't, why moisture content is a reaction condition rather than a detail, and how to source working-strength ammonia in the EU.

Safety & Enclosure — what ammonia does to eyes and airways at working concentration, the PPE that stops exposure and the PPE that only looks like it does, where fuming may and may not happen, the materials it must never contact, how to build and seal an enclosure, and what to do in the first minute of a spill or splash.

Prep & Glue-up — why the piece must be finish-sanded and fully assembled before it goes in, how surface preparation locks in the final colour pattern, why glue squeeze-out ruins more fumed work than anything else, selecting material for tannin consistency, and building test panels that predict a result rather than hope for one.

Executing the Vapour Cycle — loading and charging, the variables you control against the ones you only observe, how to read the tent from outside without breaking the atmosphere, and a failure-mode table that tells you the cause and whether it's recoverable.

Out-gassing & Neutralisation — opening a tent at peak concentration, why finish applied too early becomes a defect that can't be corrected, when a neutralising wipe is worth its colour risk and when airing is the better answer, and decommissioning the site safely.

Finishing & Colour Matching — how oil, hardwax, shellac, waterborne and lacquer each shift fumed colour and treat the ray fleck, judging test panels under the light the piece will live in, bringing an outlier board into a set without sanding, and how fumed colour ages and repairs years later.

Safety is written into the guide rather than bolted on. Working-strength ammonia is corrosive and its vapour damages airways — the protocol is a lesson, not a disclaimer.

Not a PDF, and not a video course. It's a hosted reference kept current from a single source, so when a supplier changes or a detail is corrected, your copy is corrected too. Tables and checklists sit in the lesson they belong to, so you're reading in context rather than hunting an appendix.

What this guide isn't: ebonizing with iron acetate, lye and soda ash darkening, lime treatment, and tannin pre-treatment of low-tannin species are separate guides. Different chemistry, different safety, different failure modes — the differences aren't incremental.