What reference to send, in order of accuracy
A physical cutting of the hair you buy today, at least 10cm long, is the best reference. It carries root, mid and end behaviour and can be read wet and dry. Second best is the brand's own shade tag or colour ring segment. Third is the shade code alone, which tells us the intent but not the actual dye lot you have been receiving.
A phone photograph is the weakest reference and should be treated as a starting point, not a specification. Screen white balance changes the read by more than the tolerance you care about.
How a colour lab reads it
The reference is assessed under a controlled daylight source, not salon lighting, and root, mid-length and end are read as three separate targets. Rooted and melted shades fail at the root first, because the transition length is a formulation decision rather than a colour decision.
The lab then colours a test length on the same base hair the production run will use. Base matters: the same formulation on a different origin lands somewhere else, which is why a match approved on one supplier's hair does not transfer to another's.
Tolerance you should expect and demand
Ask for the match to be approved wet and dry, and to be checked against the reference at the root as well as the tip. Ask what happens on a reorder in six months: the honest answer is a lot record, so the second batch is matched against the batch you approved rather than against a memory or a code.
No manufacturer can promise a laboratory-identical match on every shade, and any that does is selling. Blondes at level 9 and above and ash tones are the hardest; warm browns are the most forgiving.
How to run the switch without risk to a client
Approve the swatch first. Then order a single install quantity, not a stock position, and put it on one client whose hair you know well. Photograph the install at week one and week six under the same light.
Only after that install behaves do you move your stock over. A supplier who resists a one-client trial is asking you to underwrite their risk on your client's head.
Buyer Questions
Which US brand shade cards can you match?
Any of them. We routinely work from the shade tags and cuttings salons already hold — including Covet & Mane, Bohyme, The Hair Shop, Bellami and Aqua references — because that is what a switching client sends us.
Do I get to approve the colour before production?
Yes. We colour a test length against your reference and send it to you. Production only starts after you approve it wet and dry.
Will a reorder match the first order?
Reorders are matched to the lot record of the batch you approved, which is the only reliable way to keep a client's colour history intact across orders.