Why Colour Matching Paint Is a Problem (And How to Avoid It)
Here’s the mistake I see over and over again.
Someone picks a beautiful colour from a big brand (Farrow & Ball, Little Greene, Paint & Paper Library).
But when it’s time to buy, they realise the price is a stretch. So they go to the shop, ask for a colour match in a cheaper range, and hope for the best.
The result? It never really works.
Let’s be clear. This isn’t about colour being “wrong” in some obvious way. It’s not about buyers noticing that a wall is half a tone out. It’s about the fact that you chose that colour for a reason (for its depth, its warmth, its undertone, how it sits with the floor or the tiles or the light in the room) and when you try to replicate it in a different base, you lose all of that.
A colour is not just a colour. It’s a formula. And that formula depends on the pigments, the base, and the brand.
How Colour Matching Works
Spectrophotometer scanning
Stores use spectrophotometers that shine controlled white light onto a paint sample. Sensors detect the exact wavelengths reflected back. That spectral data is then compared to the machine’s database of pigment formulas to generate a “matching” recipe
Computer-driven pigment formula
The machine calculates how much of each tint to add to a base. It uses pre-programmed formulas and automated dispensers to mix the paint
Why It Often Goes Wrong
Different bases ≠ same formula
Each brand has its own base (white, tint, deep) with different pigment levels. A scanner-only picks the closest match available in that base—not the true original formula
If the original was mid‑grade or premium and you match into a cheaper base, you lose density, sheen, and undertone.
Sheen, texture, surface matter
The substrate’s texture, gloss, or finish can skew readings. A glossy sample reads differently than the actual wall
The substrate’s texture, gloss, or finish can skew readings. A glossy sample reads differently than the actual wall
Metamerism and lighting shift
A match under shop lighting can look entirely different in daylight or home lighting—this effect is called “metamerism”.
Walls display a shifting undertone throughout the day, due to light temperature reflected colours (sky and landscape outside the windows)
Machine and human error
Converting pigment mass to volume (in tint machines) is imprecise. Pumps may under- or over-deliver. Colorant settling in the cartridge makes it worse .
If the machine isn’t calibrated or the operator misreads the sheen/base code, the result drifts
Variability across batches and scales
Even the same code across batches can differ if the paints were mixed on different dates or in different machines .
Scaling formulas from a sample size to a full tin introduces slight shifts. Stores often re-run scans/formulas for larger tins .
In more simple words.
Different paint brands don’t use the same pigments. They don’t mix them in the same way. So when you try to colour match across brands, the scanner can only pick the closest approximation using what’s available. That’s why it’s never exact. And that’s why the match might look fine on a card, but completely off once it’s on a full wall in your space.
Those are the technical problems.
Now here’s the practical one: once you’ve used a colour match, you can’t repeat it. Not with certainty. Here’s why.
First: it’s not the same paint.
Colour matching doesn’t reverse-engineer the formula. It just scans the surface and picks something from that brand’s own catalogue that looks similar. But every brand uses a different base. So if you try to match a fancy brand into a trade range or DIY tin, the base pigments are already wrong. The outcome? Off.
Second: lighting lies.
The match might look fine in the shop. But get it on the wall, in natural light, or next to the original… and suddenly it’s too blue, or too warm, or too grey. It’s not a match. It’s just another colour.
Third: you can’t repeat it.
Even if by some miracle the match is passable now, what happens when you need to do a touch-up in three months? You go back, scan again, and the scanner gives you a new match. Slightly different again. Now your wall’s patchy and you’re repainting the whole room.
It’s a waste of time and a risk I don’t take.
This is what to do instead: use a proper brand.
One with a consistent range.
One that isn’t going to change their formula or discontinue the colour next season.
I use Valspar for exactly this reason.
Because they have a huge and beating range and once I pick a colour, I get the exact name and code. And I know I can get the same tin again, weeks or years later. No matching needed. No guesswork. Just paint that actually matches, because it is the same.
If you’re renovating for profit, this matters.
Start with a brand that works for your budget and your project.
Don’t fall in love with a high-end shade and then try to backtrack.
If you’re running a tight budget or working across multiple rooms or units, pick your colours from a solid, trade-accessible range from the beginning.
The quality is consistent. The range is wide enough to find exactly what I need. And once I’ve got the colour name and code, I can walk in months later and buy the exact same thing again—no scanning, no surprises.
It’s not about compromising. It’s about being smart. Once that colour’s on the wall, it has to hold the room together. Not just today, but all the way through to the final photo, the touch-up, and the buyer’s first walkthrough.
So skip the colour matching. Get it right from the start. And make it repeatable.
In conclusion:
Paint is a formula, not just a surface colour. Spectrophotometers can get close, but every step—base differences, sheen, lighting, machinery, batch variation—introduces drift.
For consistent results:
Use the same brand and base you picked from to begin with.
Stick to your colour code for easy touch-ups and reorders.
Avoid cross-brand colour matching unless you’re prepared for mismatch risk every time.
