Photographing finds for accurate identification

DetectID’s identification engine works from your photos. The rest of this guide is a list of things you can do in the field and at the kitchen table to give the engine the best chance at a confident verdict — without any extra equipment.

Why photos matter so much

Every diagnostic step the engine walks through — reading a legend, identifying a bust style, calling a mint mark, judging a grade — happens from the pixels you upload. A clear photo of a worn coin will outperform a blurry photo of a perfect one. The five rules below are worth more than any single piece of detecting equipment for getting accurate identifications.

Rule 1 — Use diffuse natural light

Bright but indirect daylight is the gold standard. Stand near a window with the coin in soft daylight. Avoid:

• Direct overhead sun. Burns out the highlights, hides the legend in shadow.
• The phone’s flash. Bounces straight back, washes out detail, creates a single hard hotspot.
• Single-source overhead lamp. Same problem — hard shadows kill the legend.

The cheapest and best lighting setup is a kitchen window on an overcast day. If you only have indoor light at night, a sheet of white paper held next to the coin acts as a bounce reflector and evens out the shadows.

Rule 2 — Plain neutral background

The engine works hardest on what’s insidethe coin’s edge. A busy background steals attention and makes auto-cropping less reliable. Use:

• A piece of plain cardboard (cereal box reverse is perfect).
• A neutral plate, slate tile, or wooden cutting board.
• The palm of your hand — warm in colour and instantly available in the field.

Avoid grass, soil, patterned fabric, glittery surfaces and shiny plastic. They confuse the auto-crop and add visual noise.

Rule 3 — Fill the frame

The coin (or artefact) should be most of the photo. Get close. Phones focus down to 5–10 cm comfortably; use your phone’s macro mode if it has one. A coin that takes up only 10% of the frame loses half its diagnostic detail to compression and resize.

Rule 4 — Include something for scale

The engine estimates diameter from any visible reference in the photo. Anything works:

• A UK coin. 1p (20.3 mm), 5p (18.0 mm), 10p (24.5 mm), 20p (21.4 mm), 50p (27.3 mm), £1 (23.4 mm), £2 (28.4 mm). Place it next to the find, in the same plane.
• A ruler. Centimetre or millimetre markings. Most useful for irregular artefacts where two measurements help.
• A fingernail. Less precise, but always available. The engine can ballpark a diameter from one in the same shot.

If you have actual scales, you don’t need a scale reference in the photo — just type the weight into the Weight (g) field on the upload form. Weight is a stronger signal than diameter for UK hammered silver.

Rule 5 — Both sides if your plan allows

On Basic and Premium you can upload more than one photo. Use them. For coins, the order that works best is:

1. Obverse (the side with the head) — primary photo.
2. Reverse (the back).
3. Edge view (Premium only) — especially valuable for milled coinage where the edge tells you a lot about grade and authenticity.
4. Close-up of a specific feature (mint mark, initial mark, a particular letter).

Both sides photographed in the same lighting conditions, on the same background, makes the engine’s job significantly easier.

Cleaning — when, and when not

A common question. Quick guidance:

• Gentle rinse with water to remove loose soil — almost always safe and improves photos.
• Soft brush on stable patina — usually fine.
• Acidic cleaners, electrolysis, ultrasonic baths — never on hammered silver, gold, or potentially valuable bronze. You’ll destroy the surface that the engine and any future Finds Liaison Officer needs.
• When in doubt, photograph dirty and clean later. The engine reads dirty surfaces fine; aggressive cleaning is irreversible.

Worn or partial coins

DetectID is calibrated for the kind of finds detectorists actually dig — worn, partial, sometimes mis-struck, often missing chunks of legend. The engine has methodology for partial-flan measurement, immobilised-legend coinages, and reading badly worn busts. Don’t skip uploading a worn coin — describe what you see in the notes field, and let the engine do its job.

The three most common photo mistakes

1. Auto-focus on the background. Always tap the coin in the viewfinder before the shutter.
2. Direct flash washing out detail.Turn flash off. Move to a window if it’s too dark indoors.
3. Coin too small in the frame. Get within 10 cm and let macro mode handle it.

A 30-second photo routine that works

1. Find diffuse daylight (window, overcast outdoors).
2. Plain background: cardboard, plate, or hand.
3. Coin next to a scale reference, all in one plane.
4. Phone 10–15 cm above, parallel to the coin.
5. Tap the coin in viewfinder to focus. Wait a beat. Shutter.
6. Flip the coin. Repeat for the reverse.

That’s it. A two-photo set in twenty seconds, and you’ve given the engine everything it needs.

Next steps

• Ready to identify? Walk through How to identify your first find.
• Got a result and not sure how to read it? Understanding your identification result.