In this guide 6 sections
Most mismatches trace to one of three causes. The tins came from different tint runs or base batches, the shade was mixed in different bases, or the walls get different light. A dealer who records shade code, base, base batch and tint time for every tin can trace a complaint to its cause.
Tins of one shade code are not always the same tin
A shade code is only a recipe. The dispenser adds colourants to a base by volume, and a small error in one colourant, such as black or oxide red, moves the result. Two tins tinted a week apart, on a machine that was refilled in between, can differ enough to show as a visible line across the wall.
Colourant canisters settle and age. The base itself comes from a factory batch, and batches differ slightly in whiteness and opacity, which no one can see by looking into the tin.
It shows on a long wall, where the roller moves from one tin to the next and the join lands under a bright window. That join is the complaint.
The same code in a different base can dry differently
Many shades can be mixed in more than one base, so a mid-tone grey may come as a pastel base formula or a medium base formula. The wet colour looks close in both tins. Opacity, sheen and the way the film dries can still differ once two coats are on the wall and a window is throwing light across them.
The counter assistant who finds the pastel base empty and reaches for the next one is making a sensible choice, with a painter waiting at the till. The trouble starts when nobody writes it down. A second order for the same flat then differs from the first, and no record says which base went into which tin.
That gap is where complaints land.
- Shade code and shade name
- Base type and the base batch number printed on the tin
- Formula version loaded in the dispenser
- Date, time and tinting machine used
- Invoice number and site name
Screens and daylight do not agree with the wall
A card, a screen and a wall disagree. A screen glows from behind and drifts with its brightness setting, so the swatch on a phone is only a hint. A card is judged under shop lighting, while the wall meets a north window in the morning and warm bulbs at night.
Two walls in one room get different light. The wall facing the window looks bright and flat, and the wall by the corridor sits in shadow, so the same paint reads darker there. Colours that match under showroom tubes can part under a warm bulb, which is why a shade looks right at the counter and wrong on site. The effect is called metamerism.
Surface counts as well. Fresh plaster drinks paint where an old painted wall does not, and a filled repair or unprimed patch takes colour differently.
Settle it on site before blaming the tin
When a complaint arrives, ask for three things. Photos of the lid label on every tin used, a photo of both walls in daylight with the lights off, and the date each coat went on.
Compare the lid labels first. Different batch numbers point to the tins. If the numbers match, look at the wall: the primer, the coat count, the roller nap, the thinning and whether anyone stirred the paint.
A tint record answers in minutes. Without one, the dealer argues from memory.
- Which tins went on which wall
- Whether the tins were poured into one bucket and stirred before use
- How many coats went on, over which primer
- Whether one roller and one thinning ratio were used throughout
- In what light the colour was judged
Keep a tint record that a complaint can be traced through
A tint record is one line per tin: date, shade code, base type, base batch, machine and invoice, written the moment the tin leaves the shaker. It can sit in the tinting software or on a sheet by the counter, so long as it is filled in every time, even in a rush.
For a large job, tint the full quantity in one session from one base batch and sell it against one order. Ask the contractor to pour the tins into one bucket before painting a continuous wall, a step called boxing, and keep one spare tin from the same session.
Start with the next big order. Write the base batch and the tint time on the invoice copy, and tell the contractor where to find the lid label.
Tint and batch record sheet
One page, two blocks. The table block has one row per tin and columns for date, shade code, base type, base batch, formula version, machine, quantity and invoice. The complaint block lists the photos to ask for, the lid labels to compare and a verdict line with four choices: tin batch, base, wall or light.
Open a blank worksheet to printQuestions owners ask
Can two tins of the same shade code look different?
Yes. Small differences in colourant dosing, in the base batch or in the age of the colourants can show once both coats are on the wall. Boxing the tins evens it out.
What is boxing paint?
It means pouring every tin meant for one continuous surface into a single large bucket and stirring them together before use. Small differences blend out first.
Why does the colour look different at night?
Warm and cool bulbs lean toward different parts of the spectrum, so a shade can shift between daylight and evening light. Judge it in daylight and again at night.
How long should a dealer keep tint records?
Hold each record for the whole defect liability period written into your contractors’ contracts, and longer for large projects. Ask them how many months that period runs.