You bring your car in with a dent in the door. The bodyshop looks it over and tells you they will need to spray part of the wing too. That sounds odd. The wing is fine. Nobody hit the wing.
It is one of the questions we get asked most often, and it is rarely explained properly. So here it is, start to finish, without the jargon.
The short answer is this. Getting the colour right is the hardest part of any car dent paint repair, and the only reliable way to make a repair invisible is to fade the new paint gently into the panel next door. If a bodyshop is not doing that, you will usually see the difference the first sunny day after you get the car back.
Every car has a paint code, but the code is only the starting point
Somewhere on your car, usually on a sticker inside the driver’s door frame, under the bonnet or in the boot, there is a paint code. It might look something like LY9C or KH3. That code tells a paint supplier the exact recipe your car was mixed to on the day it was built.
So far, so simple. Mix the code, spray the panel, job done.
Except it does not work like that, and here is why.
Your paint is not the colour it was when it left the factory
Paint changes over time. Not dramatically, not in a way you would ever notice day to day, but it changes.
- Sunlight. Ultraviolet light slowly breaks down the pigments and the lacquer on top of them. Reds and dark blues suffer the most.
- Washing. Every wash, especially a rough brush at a hand wash, takes a tiny amount off the top and dulls the surface very slightly.
- Weather and road grime. Salt in winter, bird mess, tree sap and heat all take their turn. You can read more about what this does to the top layer in our guide to car paint peeling damage repair.
- Where the panel sits. A roof and a bonnet get far more sun than a lower door, so the same car can be very slightly different shades from top to bottom.
Now think about what happens if a bodyshop mixes your paint code perfectly and sprays it on. They have just put brand new, factory-fresh colour next to five-year-old, sun-softened colour. Even if the mix is technically correct, it will sit there like a patch. Correct on paper. Wrong in real life.
That is the whole problem in one sentence. A perfect factory mix is not the same as a perfect match to your actual car.
How a technician really matches your colour
A good refinishing job is a small process, and it happens before anyone picks up a spray gun.
1. Reading the panel. The technician cleans and polishes a small area of your existing paint, then takes a reading off it using a colour reading tool called a spectrophotometer. It shines light at the panel and measures exactly what comes back. That gives a picture of what your paint actually is today, not what it was in the factory.
2. Finding the closest variant. Car makers do not use one single version of each colour. A single silver might have dozens of official variants, because paint batches vary and factories vary. The reading is matched against these variants to find the closest one.
3. Mixing and adjusting. The paint is mixed by weight on digital scales, then tweaked by eye and by experience. A tiny amount more of one pigment can be the difference between right and nearly right.
4. Spraying a test card. This is the step most people never hear about. Before anything touches your car, the technician sprays a test card, sometimes called a spray-out card, using the same gun, the same air pressure and the same number of coats they will use on the panel. The card is dried, lacquered and then held against your car in daylight. If it is not right, they adjust and do it again.
Only when the card disappears against your paint does the actual repair start.
What paint blending is, and why the next panel gets sprayed
Here is the part that saves the job.
Even with a brilliant match, laying new paint up to a hard edge creates a line. Your eye is very good at spotting straight lines and sudden changes. It is far less good at spotting a change that happens gradually.
So instead of stopping the new colour at the edge of the repair, the technician sprays it in progressively thinner layers out across the neighbouring area. The new colour fades into the old colour over a hand’s width or more. Then lacquer goes over the whole lot so there is no join in the shine either.
That is paint blending. It is why a dent on a door can mean light spraying into the wing or the rear quarter. The bodyshop is not padding the bill. They are removing the one thing that gives a repair away.
On some panels this matters more than others. A wing sits right next to the bonnet, the bumper and the headlight, so any difference is visible from several metres away. We break this down panel by panel in our guide to car dent paint repair cost by panel.
Some colours are far harder to match than others
Not all paint is equal. Some finishes are forgiving. Others will punish any shortcut.
| Paint type | Why it behaves this way | How hard is it to match? |
|---|---|---|
| Solid white, solid black | One layer of colour, no sparkle to line up | Easiest, though solid black shows polish marks badly |
| Metallic silver and grey | Tiny aluminium flakes that must lie the same way as the original | Moderate, blending strongly recommended |
| Metallic dark blue and dark grey | Dark base plus flake, so both the shade and the sparkle must agree | Hard, blending needed |
| Reds and bright oranges | Pigments fade fastest in sunlight, so older cars drift furthest from the code | Hard, especially on cars over five years old |
| Pearl and three-stage finishes | A colour coat, then a pearl coat, then lacquer, all built up in stages | Hardest, test cards are essential |
With metallic and pearl paint, it is not just the colour that has to match. It is the way the light bounces. Those flakes and pearl particles need to sit at the same angle and the same depth as the ones already on your car. Spray it too wet, too dry, too close or too far away and the shade shifts, even with the exact same tin of paint. That is why an experienced sprayer matters as much as the mix.
Why your car looks a different colour in the workshop
You may have picked a car up, looked at it under the workshop lights, been perfectly happy, then seen it in the car park and thought something was slightly off.
You are not imagining it. Two colours can look identical under one light source and clearly different under another. The technical name for this is metamerism, and it is exactly why any decent bodyshop checks the match in natural daylight rather than trusting the lights above the booth. Workshop strip lights, LED panels and low winter sun all show colour differently.
This is also one reason proper refinishing happens inside a controlled spray booth rather than in an open unit. Booths give clean air, steady temperature and consistent lighting, and they keep dust off the wet paint. They are also a legal safety requirement, because modern two-pack paints contain isocyanates. The Health and Safety Executive sets out what bodyshops must do in its guidance on safety in isocyanate paint spraying. If a repairer is spraying your car outdoors or in the corner of a unit, that tells you something about the rest of their standards too.
What a rushed repair looks like six months later
Cheap paint repairs rarely look bad on collection day. They look bad later. Common signs:
- A panel that only stands out in sunshine. Fine under cloud, obviously a different shade the first bright morning.
- A visible edge or halo where the new paint was stopped dead instead of blended.
- Sparkle that does not line up on metallic cars, so the panel looks flat or looks brighter than the ones on either side.
- Lacquer that dulls or peels early, because it was sprayed too thin, too fast or over a surface that was not prepared properly.
- Dust or bits trapped under the shine, which usually means it was not sprayed in a booth.
There is another reason to care beyond how it looks. A mismatched panel is one of the first things a buyer or a trade valuer notices, and it makes them assume the car has had accident damage, whether it has or not. A tidy repair protects your car’s value. A visible one costs you money later.
If the paint on your car is still intact and the damage is only a shallow dent, you may not need spraying at all. Our comparison of paintless dent removal versus traditional repair explains when each one is the right call, and keeping your original factory paint is always the best possible match.
Questions worth asking your body shop
You do not need to be an expert. You just need to ask four things.
- Will you take a colour reading off my car, or just mix to the paint code?
- Will you spray a test card before you spray my car?
- Will you blend into the next panel, and is that included in the price?
- Is the work sprayed in a booth, and is it guaranteed?
If the answers are yes, yes, yes and yes, you are talking to someone who takes the job seriously. If a quote is a lot cheaper than everyone else’s, one of those four is usually missing. You can see how the numbers normally stack up in our breakdown of car dent and paint repair costs.
Does new paint ever match old paint perfectly?
Honestly, a perfect match straight from the code is rare on any car that has spent a few years outside. What a skilled bodyshop delivers instead is a match your eye cannot find. The colour is read from your car, adjusted, tested and then faded out into the panel next door so there is no line for you to catch. Done properly, you will not be able to point at the repair, and neither will anyone else.
That is the real answer to why we sometimes spray part of a panel that was never damaged. It is not extra work for the sake of it. It is the difference between a repair and a patch.
Get it done properly the first time
At Infiniti Motor Group in Barking, we are a fully insurance-approved bodyshop. Our technicians use manufacturer-approved repair methods and colour matching technology, and all our work is covered by warranty. We also handle the insurance claim for you from start to finish, and courtesy cars are available so you are not left without a vehicle.
Whether it is a small dent, a scuffed bumper or a full accident repair, we will tell you honestly what your car needs and what it will cost. If you are not sure how bad the damage actually is, start with our guide to car paint scratch repair and then bring it to us for a free look-over.
Call us on 020 8798 2590 or pop in to Unit 12, Barking Industrial Park, Alfred’s Way, Barking, London, IG11 0TJ.