5 lighting mistakes that hide holograms in your paint

By the end of October the light is gone by six in the evening, and if you're still polishing, you're doing it indoors under the ceiling lights. The bonnet gleams, the paint looks flawless, job done. Then the first clear morning in March comes round, you head out, and fine rainbow haze shimmers around every reflection of the sun. The paint hasn't got worse over the winter. The October light just wasn't honest enough, and an inspection light would have shown you back then.

Five lighting mistakes let holograms, swirls and sealant residue slip through unnoticed. Degrease the paint first, keep the light low and flat, hold your distance and match the colour temperature to the paint, and your lamp shows you in autumn what normally only the spring sun gives away.

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1. Diffuse ceiling light hides the holograms from polishing

Broad ceiling light hits the paint from lots of directions at once and fills the fine edges of holograms with light, so paint full of holograms looks smooth and finished underneath it.

An overcast sky does exactly the same: the cloud cover scatters the light, and even paint riddled with wash marring looks calm under it. Fluorescent tubes on the ceiling do the same, often with a colour rendering index below 80. Holograms, on the other hand, are directional micro-scratches up to two microns deep, and it's almost always a rotary that leaves them. They only show up when a single, hard point of light travels across the panel.

The fix is a second light in your hand, held at about 45 degrees between lamp and eye. An inspection light with a focused spot, swept low across the paint, turns that even gloss into a pattern you can actually read. If the rainbow haze shows up, a fine anti-hologram polish takes it out. The Koch-Chemie Micro Cut "M2.02" High-Gloss Anti-Hologram Polish works at cut level 2.5 and gloss level 9.0 and is made for holograms and fine scratches from 4,000 grit and finer.

For the finish, run it on a dual-action polisher with a soft, fine-cell pad in a cross-hatch pattern. Push it past 1,500 to 1,800 rpm and a finishing polish dries out fast and burns fresh marks into the paint. How holograms come about in the first place is covered in detail in Anti-hologram polish: holograms only appear when you polish.

The sun is still the toughest second opinion. Direct sunlight is a huge point light source and shows every bit of haze you missed indoors. If you polish in autumn, roll the car outside for five minutes on the next dry, clear day and walk once around it from a distance. Whatever shows up there is the same information March would otherwise hand you, just half a year earlier.

2. Polish residue hides scratches until you degrease

Polishes contain oils as lubricants, and those oils settle into the fine scratches and bend light almost the same way the clear coat does, which is why freshly polished paint often looks better than it really is.

Under the lamp an oily panel looks glass-smooth. After two or three washes or a heavy downpour the oils are gone and the scratches are back out in the open. The same goes for Quick Detailer, spray sealants and waxes: if you only check afterwards, you're inspecting the fill, not the paint. That's why the final inspection always comes before the sealant, never after.

The step for this is an alcohol-based degreaser that strips oil, wax and polish residue completely. The Koch-Chemie Panel Preparation Spray "Pps" Degreaser & Inspection Spray is ready to use, goes straight on from the spray bottle without dilution and flashes off without leaving a film. Koch-Chemie doesn't call it an inspection spray by accident: only after the wipe-down does the panel show its real condition.

Work panel by panel. Mist one panel, wipe it off in straight passes with a clean, short-pile microfibre cloth and check it with the lamp right away. If haze or fine scratches turn up, the polishing step wasn't finished yet. That's not a step back, it's exactly the information you want before the sealant goes on.

According to Koch-Chemie, Pps is based on isopropyl alcohol and butoxyethanol and is formulated for freshly polished clear coats, as well as for plastic and metal. New cars and freshly prepped cars from the dealer often carry gloss products with filling oils on the paint, too. An inspection pass with degreaser before your own first polish shows you what condition you're really taking on.

3. A lamp held too close to the paint glares the defects away

Hold the inspection light just a few centimetres from the paint and you get an overbright hotspot that overloads your eye, so fine haze at the edge of the beam simply disappears.

For inspection, 30 to 50 centimetres is the distance that works. The beam is then big enough to read a whole area, and the hotspot no longer dazzles. For holograms, a very flat angle helps, almost parallel to the paint. In that position the fine polishing marks cast the biggest shadow and show up as haze.

Movement matters at least as much. A fixed light on a tripod only shows the scratches that happen to sit at the right angle to your eye. Sweep the light slowly over the panel and keep changing your own position, once from the front, once from the side, once over your shoulder. Whatever shows up in all three views is real. Whatever only flickers at one angle is usually a reflection.

Your phone torch is a stopgap. It does give you a point of light and shows coarse wash scratches, but it's weak, scatters unevenly and renders colours poorly. It's fine for a quick look before the wash, not for signing off the paint after polishing. Then there's the practical side: when you're on the machine, you need both hands and a light you can put down or stand up.

With the light in your hand, it's worth a look into the wheel arches too. Brake dust between the spokes jumps out under the lamp straight away. If you're busy drooling over the BMW M3 with M Carbon ceramic brakes and quietly wondering whether G80 or G81 is the right nerd answer: carbon-ceramic discs don't like point impacts. Clean them with a soft wheel brush, no tools on the disc and no grease on the friction surface.

4. Warm white light swallows swirls on black paint

The colour temperature of a light has a say in which defects you see, because dark paints swallow warm light, while light paints bounce cool light back so hard that fine scratches get lost in the gloss.

Colour temperature is measured in Kelvin. Warm light between 2,500 and 3,500 Kelvin has a high share of yellow and red and suits white, silver and light colours. Neutral white light from 4,500 to 5,500 Kelvin comes close to daylight and is the go-to standard for paint correction. Black and dark shades need cool light around 6,000 to 6,500 Kelvin, because the higher blue share picks out the fine edges in dark clear coat.

The second figure on any good light is the colour rendering index, CRI or Ra for short. On a scale up to 100, it tells you how true to life a lamp shows colours. For paint inspection it should be above 90, ideally above 95. Many inspection lights let you switch through several steps between 2,500 and 6,500 Kelvin. That's exactly what you need when there's more than one paint colour in front of you.

What the lamp then shows decides the polish. Dense wash marring and dull patches need a compound like the Koch-Chemie Heavy Cut "H9.02" Heavy Compound with cut level 9.0, which takes out sanding marks down to 1,200 grit and needs a fine follow-up polish afterwards. Check single deep scratches with your fingernail first: if the nail catches, the scratch usually goes down into the base coat and it's a job for the body shop, not the machine.

So before any compound, take a paint thickness reading. A factory finish of primer, base coat and clear coat usually measures 100 to 160 microns in total. If a panel reads well above that, say over 200 microns, it has probably been resprayed. If it reads well below, tread carefully, because there's not much reserve left in the clear coat. How much removal your paint can take is covered in How often can you polish a car.

5. A focused beam misses sealant residue

A focused beam is ideal for scratches, but barely shows where a sealant has been left on too thick, because you only spot that kind of residue as dark, cloudy islands in the broad, soft light of a big lamp.

This mostly matters in autumn, when cars get sealed one last time before winter. A ceramic coating or a polymer goes on, flashes off briefly and then comes off with a cloth. If a spot stays too wet, it cures as an uneven patch. Under a spot lamp you'll hardly notice, because the beam is too small. A big light whose reflection travels across the whole door shows those high spots straight away.

The fix is timing and the right cloth. Right after the wipe-off, light up the panel with broad, soft light and buff residue off with a second, fresh cloth while it's still soft. The THE COLLECTION "Allround / Coating 300" short-pile edgeless microfibre cloth (300 GSM) is built for exactly that: short pile, no hard edge, 300 grams per square metre and so enough reserve to pick up product residue instead of smearing it around.

Once residue has cured, no cloth will save you. The spot then comes off with a fine polish like the M2.02 and gets resealed. That's why this check belongs before the coating cures, not the next morning. Which sealant is actually worth it before winter is explained in Paint sealant or wax: 5 situations before winter.

Broad light shows one more thing no polish will make disappear: orange peel. The wavy texture comes from the factory paint process and distorts reflections like the skin of an orange. In broad light you can see how pronounced it is. That's not a care mistake, and it's no reason to go at it with a compound either. Flattening it takes wet sanding, and that belongs in experienced hands.

Four products cover the work under the lamp

For an honest paint inspection in autumn, a degreaser, a heavy and a fine polish and a good wipe-off cloth are all you need, because the lamp brings the defects to light and the products fix them.

The Koch-Chemie Pps comes first, after every polishing step and before every sealant. The 500 ml spray bottle covers plenty of inspection passes on one car, and if you polish regularly, grab the 5 litre can for refills. Its limit: it removes oils and gloss residue, not scratches. Whatever shows up afterwards, only polish will fix. According to the safety data sheet it is highly flammable and its vapours can cause drowsiness, so when you work indoors, keep the door open and stay well clear of any radiant heater.

The Heavy Cut H9.02 is the correction stage for dense swirls and dull patches, the Micro Cut M2.02 the finish against holograms. Both come in 250 ml to get started and as a litre for several cars. The H9.02's limit is printed on the bottle: it isn't a finishing polish and doesn't go on the paint without a thickness reading. A modern clear coat is only about 30 to 60 microns thick.

The Allround / Coating 300 takes off degreaser, polish residue and sealant. For a full paint correction, keep several cloths on hand, because a cloth that has already carried polish has no business touching a fresh sealant. There's more on polishing and picking the right polish in the Polishes category and in Spotting swirls in your paint.

Detailing1-Insight: We get questions like: does the polish leave holograms on black paint? The answer depends less on the polish than on the light when you wipe it off. Our order: Pps first, then the lamp low and flat at 30 to 50 centimetres, on black with cool light around 6,500 Kelvin. Whatever you see then will still be there in March. If you put Quick Detailer on after polishing and only check afterwards, you're inspecting the fill, not the paint.