How to restore peeling Hiroshi Nagai prints from old frames

Assessing the damage and print type

Hiroshi Nagai’s work was primarily produced as offset lithographs in the 1970s–80s, often on medium-weight coated paper (120–170 gsm). Peeling typically occurs when low-quality adhesives or acidic mounting boards degrade over time. The Fine Art Trade Guild defines offset lithography as a commercial process distinct from archival giclée, which uses pigment inks on cotton-rag paper (250–310 gsm).

Examine the print under raking light to identify delamination between the ink layer and substrate. If the peeling is confined to the edges, the damage is likely adhesive failure. If the ink itself is flaking, the print may have been exposed to moisture or direct sunlight, accelerating the breakdown of the lithographic varnish.

Cleaning and stabilising the print

Begin by removing the print from the frame and placing it face-up on a clean, flat surface covered with acid-free tissue. Use a soft-bristle brush (e.g., a makeup or conservation brush) to gently remove dust and particulate matter from the surface. Avoid compressed air, which can further lift unstable ink.

For adhesive residue on the verso, apply a small amount of distilled water to a cotton swab and lightly dab the affected area. If the residue persists, use a vulcanised rubber sponge (e.g., Mars Plastic) in circular motions. Do not use solvents, as they may migrate through the paper and dissolve the ink.

If edges are lifting but the print is otherwise stable, apply a thin strip of Japanese tissue paper (e.g., Kozo or Mitsumata, 8–12 gsm) to the verso using a reversible adhesive like BEVA 375 film or wheat-starch paste. Avoid pressure-sensitive tapes or PVA glues, which become irreversible over time.

Rehousing with archival materials

Reframe the print using 100% cotton-rag matting (4-ply, acid-free) and a backing board of the same material. The mat window should be cut with a bevel to prevent the print from touching the glazing. For standard sizes (e.g., 50x70 cm / 20x28 in), a mat border of 7–10 cm (3–4 in) is typical.

Select UV-protective glazing with at least 97% UV filtration (e.g., Tru Vue Museum Glass or Artglass AR 70). The Canadian Conservation Institute recommends glazing for all works on paper, as UV exposure is the primary cause of ink fading and paper embrittlement. Ensure the frame is sealed with acid-free tape to prevent dust ingress.

For hanging, position the centre of the print at ~145–150 cm (57–60 in) from the floor, adhering to the two-thirds rule above furniture. Avoid placing the print in direct sunlight or areas with high humidity (above 60% RH).

When to consult a professional conservator

If the print exhibits extensive ink loss, cockling (warping), or foxing (brown spotting), professional intervention is required. The American Institute for Conservation’s Find a Conservator directory lists specialists in paper conservation. Costs for treatment range from $300–$800 USD, depending on the complexity of the damage.

Conservators may employ techniques such as humidification and flattening under controlled pressure, or localised consolidation of flaking ink with methyl cellulose or Klucel G. For offset lithographs, avoid aqueous treatments, as they can cause ink bleed. A conservator will also assess whether the print’s substrate can withstand reframing without further stress.

Preventing future damage in a family home

In residential settings, matte finishes are preferable for offset lithographs, as they minimise glare and conceal minor surface imperfections. Glossy finishes, while vibrant, accentuate any existing peeling or scratches. The MoMA’s What Is a Print? notes that matte surfaces also reduce the visibility of fingerprints, a common issue in high-traffic areas.

For display in a family home, avoid placing prints above heat sources (e.g., radiators) or in rooms with fluctuating humidity (e.g., kitchens, bathrooms). If the print is a gift (e.g., for a baby shower), consider a shadowbox frame with a deep mat to protect it from accidental contact. Rotate the print out of direct light every 6–12 months to ensure even exposure.

• Matte vs. glossy: Matte finishes (e.g., Hahnemühle Photo Rag) diffuse light, reducing glare; glossy finishes (e.g., Ilford Gold Fibre Silk) offer higher contrast but show surface flaws.
• Offset vs. giclée: Offset lithographs (like Nagai’s) use ink applied to a metal plate; giclées spray pigment ink onto cotton-rag paper, offering superior archival stability (100+ years).