How to identify an old painting

What physical evidence shows a painting is old?

Age shows in materials and construction that are hard to fake consistently: the weave of the canvas, how it is attached, how the panel was cut, and how the paint has cracked and discolored over time.

• Canvas weave

  Hand-woven linen, standard before the nineteenth century, has irregular threads with thick slubs. Machine-woven canvas, increasingly common from the mid-1800s, is even and regular. A regular cotton duck canvas suggests the twentieth century.

• Stretcher and strainer

  Keyable stretchers with wedges in the corners appear from the later eighteenth century and became standard in the nineteenth. Fixed strainers are common on earlier and cheaper works. Modern machine-cut stretchers with staples are twentieth-century.

• Nails, tacks and staples

  Hand-forged nails with irregular heads, then machine-cut tacks through the nineteenth century, then wire nails and finally staples, which on a canvas usually mean restretching or manufacture after about 1950.

• Panels

  Oak panels were typical in the Low Countries and northern Europe; poplar in Italy. Bevelled edges on the back and tool marks from hand planing are characteristic of older panels. Specialists can date oak panels by dendrochronology.

• Craquelure

  Age cracks follow the movement of the support: fine networks on canvas, cracks that run with the grain on panel. Uniform, shallow cracks that sit only in the varnish, or cracks drawn in, are warning signs of artificial aging.

• Relining and restoration

  A second canvas glued to the back (a relining) is common on old canvases and shows that the painting has needed structural care. Retouching shows as areas that look different under UV light.

How do you identify an old painting step by step?

Examine the back and edges first, record construction details, then the surface, and only after that look at style, subject and signature.

1. Examine the back before the front

   Note the support, the stretcher type, the fixings and any labels. Photograph everything with and, if safe, without the frame.

2. Look at the edges

   Check the tacking margins for original tack holes, cusping (the scalloped distortion of threads near the original tacks) and evidence of cutting down or relining.

3. Study the surface in raking light

   Look at the craquelure pattern, the thickness of the paint and the condition of the varnish. A discolored yellow varnish is typical of old oil paintings and should only be removed by a conservator.

4. Check under UV light

   An inexpensive 365 nm UV torch makes old natural-resin varnish fluoresce greenish and shows later retouching as dark patches. It is a guide, not a proof, but it reveals restoration quickly.

5. Place the style and subject

   With the age range established, compare the style with dated museum works: Dutch Golden Age genre scenes, Italian devotional panels, eighteenth-century British portraits, Barbizon landscapes, Victorian narrative painting.

6. Research labels and signature

   Transcribe labels and the signature and search them within the period and region you established. Old collection labels and inventory numbers can lead to auction catalogs and archives.

7. Decide between original, copy and later imitation

   Many old paintings are period copies or later works in an earlier style. Decide which your evidence supports; all three are "old paintings", but they are different objects in research and in the market.

What clues help date and place an old painting?

These examples show how construction details narrow an old painting's date and origin before any artist is considered.

• An oak panel with bevelled back

  A small genre scene of a tavern interior on a thin oak panel, bevelled on all four sides, fits seventeenth-century Netherlandish practice. Dendrochronology could give the earliest possible felling date of the tree.

• A relined canvas with a London stencil

  A portrait relined in the nineteenth century carries an old auction stencil on the stretcher. The relining tells you the canvas underneath is older still; the stencil may lead to a sale record.

• Keyed stretcher, machine-woven canvas

  A landscape in the manner of Claude Lorrain on a regular machine-woven canvas with a keyed stretcher stamped by a nineteenth-century supplier is a nineteenth-century work in a seventeenth-century style, not a seventeenth-century original.

• Craquelure that ignores the support

  A supposedly eighteenth-century painting with a perfectly uniform fine crackle across the whole surface, unrelated to stretcher bars or weave, suggests an artificially induced crackle varnish.

• Pigment clues from a conservator

  Prussian blue was discovered in the early eighteenth century and titanium white only became widely available around 1920. A conservator's analysis finding titanium white in an "Old Master" settles its date, unless it is limited to a restoration.

What mistakes do people make with old paintings?

The commonest mistakes damage the evidence or confuse "old-looking" with "old".

• Cleaning with household products

  Soap, solvents, potatoes and bread have all been tried, and all can remove glazes, signatures and original paint along with the dirt.

• Equating dirt and dark varnish with age

  Decorative copies are often toned down with brown varnish to look old. Real age shows in construction and materials, not in color.

• Removing old labels and stretchers

  Replacing a stretcher or discarding old labels during reframing destroys provenance and dating evidence. Keep everything, even fragments.

• Assuming old means valuable

  Many old paintings are anonymous decorative works or period copies with modest market value. Age is necessary for an important Old Master, not sufficient.

• Ignoring restoration

  Heavy overpainting can change a painting's appearance, and sometimes its apparent attribution. UV examination and a conservator's report put the surface in context.