How to Photograph a Porcelain Mark for Authentication

Open any dealer's inbox during a typical week and a third of the messages will be the same: a hopeful collector's phone photo of a vase's underside, taken at arm's length, with the kitchen ceiling light blooming off the glaze in a single white reflection that obscures the entire mark. Underneath: "Can you tell me what this is?" The honest answer is almost always no — not because the mark isn't there, but because the photograph isn't.

This guide is for the moment between "I found something interesting" and "I'd like a professional opinion." Do it well and a dealer can give you a useful read in a single email. Do it poorly and you'll get a polite "please send better photos," which is what most messages quietly receive.

Why the photograph carries the case

When a piece goes through a proper attribution at a major house, specialists handle it in person — they tilt it under raking light, weigh it, run a fingertip along the foot rim. None of that travels through a phone. The single photograph of the mark has to do an outsized share of the work.

A useful authentication photo gives the viewer four things at once: the characters (legible enough to identify the script and check stroke order), the pigment (true color, with the slightly bleached look of underglaze cobalt or the granular sit-on-top quality of iron-red enamel), the brushwork (fluid or hesitant — a key tell for period versus later homage), and the glaze around the mark (pooling, bubbles, the line where the foot rim was wiped clean before firing). Miss any one and the dealer has to ask for another photo, which is the friction that ends most authentication conversations before they start.

What dealers and auctioneers actually need

Before touching the camera, it helps to know what the person on the other end is looking for. A specialist examining a mark photograph runs through a checklist that's roughly the same whether the piece is being valued for insurance, considered for consignment, or judged in a club discussion. The list below is what we look for first, in the order we look for it.

| What we check | What we want to see in the photo ||---|---|| Character legibility | All 4 or 6 characters readable, no glaze flare across them || Script style | Enough resolution to tell kaishu (regular) from zhuanshu (seal) || Pigment | True color, not yellowed by warm room light or bluish from cool LEDs || Brushwork rhythm | Sharp enough to see whether strokes were drawn fluidly or copied hesitantly || Mark border | If a circle, square, or cartouche surrounds the mark, the whole border is in frame || Glaze and foot context | At least a thin ring of surrounding glaze and foot rim visible, not cropped tight to the characters || Wear pattern | The slight matte band where the foot has touched shelves for a century || Scale | Something in the frame that anchors the size — a coin, a ruler, even a thumbnail |

If you photograph for that list, your photo will be in the top 10% of what specialists receive in any given week. Most of the work is in the lighting.

Equipment you already own is enough

You do not need a macro lens or a copy stand. Almost every authentication-quality photograph circulating in the trade now is taken on a phone — what matters is how you use it.

A modern phone (any iPhone or Android from the last five years) has enough resolution to capture a six-character mark at a distance where the lens can hold focus. Minimum focus distance is usually around 10-15 cm; getting closer than that produces the soft, slightly blurry image that's the second-most-common reason photos fail. If your phone has a dedicated macro mode, learn where to tap into it. If it doesn't, shoot from roughly 15 cm away and crop later.

A real camera with a 50mm or macro lens is marginally better, mostly for manual control over exposure and white balance.

Lighting that reveals rather than hides

Lighting is where most amateur photographs fail. The instinct is to turn the piece toward the brightest light in the room — a kitchen ceiling fixture, a window — and shoot. The problem is that direct overhead light hits the glassy glaze and reflects straight back into the lens as a hard white flare, blanking out exactly the area you want to read.

The fix is diffused side light. Two reliable setups:

Window, indirect: Place the piece on a table about a meter back from a north-facing window, or any window that doesn't have direct sun streaming through it. The light arrives soft and from one side. Turn the piece so the mark is angled slightly toward the light, not directly into it.

Two-lamp tabletop: Two desk lamps with white shades, one on each side of the piece at 45 degrees, both pointed at a white sheet of paper or fabric draped behind the piece (the paper bounces the light back as a soft fill). Avoid mixed color temperatures — two cool-white LED bulbs are fine; one warm and one cool will make the pigment unreadable.

Whatever the setup, the test is simple: tilt the piece slowly under the light and watch the mark. The moment the characters look sharp and the glaze stops flaring is the moment to lock the angle and shoot. If you have to chase the perfect angle for thirty seconds, your lighting is too harsh — soften it (move further from the lamp, add another layer of paper diffusion) and the angle becomes forgiving.

Avoid on-camera flash. The phone's flash is a point source millimeters from the lens; it produces the worst possible flare on glazed surfaces. Turn it off.

Composing the shot

With the lighting solved, composition is the easy part. Three rules cover most cases.

Fill the frame, but leave a margin. The mark should occupy roughly 60-70% of the frame, with a thin band of foot rim and surrounding glaze visible around it. Cropping tight to the characters loses the foot context that helps date the piece. Leaving the mark as a small island in a sea of empty floor loses resolution.

Shoot square to the surface. The camera lens should be parallel to the underside of the piece, not tilted. If the foot rim is wider on one side of the frame than the other, the mark will appear keystoned and the brushwork will look distorted. The fastest way to get this right: rest the piece face-down on a soft cloth, then hold the phone directly above it, with the screen parallel to the floor. Many phones show a level indicator in the camera app — turn it on.

Add a scale reference. A small ruler, a coin (most readers know the size of a US quarter, a UK pound, or a euro), or even a fingertip in the corner of the frame tells the viewer instantly whether they're looking at a teacup mark or a meiping vase mark. Scale changes which forgery patterns are plausible — large pieces are forged at very different price tiers than small ones.

After the main shot, take a second photograph that includes the whole foot rim and a portion of the side wall. The combination of mark and foot profile is far more diagnostic than either alone. Used together, the pair lets a specialist cross-check the characters against the structural evidence the mark is supposed to corroborate.

Common mistakes worth avoiding

A handful of recurring errors account for most of the photos that come back unreadable.

Single overhead light source: produces hard reflections. Move to diffused side light.

Glass or plastic between camera and mark: people sometimes photograph through a display case or a sheet of acrylic. Both layers add glare and dull the color. Take the piece out.

Auto white balance on warm tungsten light: the camera tries to "correct" the warmth and pushes the cobalt blue toward gray-green. If you can set white balance manually to match your light source, do; otherwise shoot under daylight-balanced lamps.

JPEG processed by a heavy "scene" filter: phones sometimes auto-apply HDR or "vivid" modes that crush the subtle pigment differences specialists rely on. Shoot in the most neutral mode your phone offers; on iPhone, that's often turning off Smart HDR or shooting in ProRAW.

One photo only: send three — one of the mark, one of the foot rim and underside as a whole, one of the side of the piece showing the overall form. Specialists assess marks in the context of the body they were painted on.

If your finished photo passes a simple test — can you, holding it on your phone screen, read every character clearly without zooming past the resolution limit? — it will pass for most dealers. If you find yourself pinching to zoom to verify a stroke, the dealer will too, and what they see at 400% is usually pixel noise.

Sending the photos

When you send the images on, three small things help the response rate. Include the dimensions of the piece in millimeters (height, mouth diameter, foot diameter) — even rough measurements with a kitchen ruler are useful. Mention any history you have ("inherited from my grandfather, who collected in the 1960s") without overstating it. And send the original full-resolution files, not the compressed copy that an email client offers to attach. Compression destroys exactly the fine detail the photograph was taken to capture.

The same images can do double duty. Once you have authentication-quality photos of a piece, they're also the photos that anchor a proper sale or insurance valuation later, and the photos a future heir will pass on with the object itself.

Common questions

Do I need a macro lens to get a good mark photo?

No. A modern phone camera held at its minimum focus distance — usually around 10-15 cm — captures more than enough detail for authentication. A real camera with a macro lens is a marginal improvement, mostly in manual control over exposure. Spend your effort on lighting and stability instead. A phone on a small tripod, with diffused side light, beats an expensive lens handheld under a ceiling fixture.

Should I clean the piece before photographing the mark?

A gentle dry dust with a soft brush, yes. Wet cleaning, no — not before authentication, anyway. The accumulated dust pattern, water staining, and old shelf-line wear are all evidence specialists use to assess age. Scrubbing them off makes a piece look suspiciously fresh and removes information that supports a genuine attribution. Once a piece is authenticated, your dealer can advise on appropriate cleaning.

What if my phone's macro mode produces blurry shots?

Two usual causes. First, you may be too close — pull back slightly and let the phone find focus, then crop into the resulting image. Second, hand shake at close range is severe; rest your elbows on the table, hold your breath as you shoot, or use the phone's self-timer to remove the press-the-shutter wobble. If blurriness persists, the room is probably too dim and the phone is using a slow shutter speed — add light rather than relying on the phone's low-light processing.

Is iron-red harder to photograph than underglaze blue?

A little. Iron-red sits on top of the glaze and reflects more directly than cobalt blue, which sits beneath. The same diffused side-light setup works for both, but with iron-red be especially watchful for glare on the raised enamel. Tilt the piece a few degrees more steeply, so the light grazes the surface rather than hitting it head-on. To learn how the pigments differ at the level of firing and brushwork, our piece on iron-red versus underglaze-blue marks covers both.

How many photos should I send for one piece?

Three is the working minimum: the mark itself filling most of a frame; the full underside including foot rim and a portion of the side wall; and the side of the piece showing the overall silhouette. If the piece has unusual features — a chip, a kiln spur, an inscription elsewhere — add a photo of each. More is generally better than fewer; specialists scroll quickly past photos they don't need but cannot conjure ones you didn't take.

Further reading

Chinese Vase Stamps: A Complete Reference — every mark type and convention you might encounter on a base.

Kangxi Reign Marks: Identification — a worked example of how a single reign's marks reward careful photography.

Studio and Hall Marks Beyond Reign Marks — what to look for when the mark isn't a standard reign.

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Modern hand-painted Jingdezhen works in the imperial tradition, every mark documented and photographed to the standards above.