PMG Mending, Repair, and Filling
In progress: Seeking additional comments and images to develop this section
The Photographic Materials Conservation Catalog is created and maintained by the Photographic Materials Group of the American Institute for Conservation of Historic and Artistic Works as a convenience for the membership.The treatments, methods, or techniques described herein are provided for informational purposes. The reader assumes responsibility for any application results. Best professional judegment is necessary when using or interpreting information provided.
Purpose of Mending, Repairing, and Filling Photographic Materials
- Maximize the chemical and physical stability of the object.
- Minimize changes in the image, binder, and support.
- Provides basis for creating aesthetic reintegration of damaged photographic materials.
- Stabilize the object to facilitate display, digitization, access by researchers, etc.
Factors to Consider Before Mending, Repairing, or Filling
- Any attachment to the photograph needs to be of quality materials that will not chemically or physically alter the original material in accordance with AIC Code of Ethics.
- Materials and methods of attachment that can be safely reversed at a later date are preferred in accordance with AIC Code of Ethics.
- Replicating the color, reflectance (gloss or sheen), and surface texture of the original will visually minimize fill repairs on many photographic materials.
- Toning fills before insertion will create a more even tone and reduce the likelihood that colorant materials will imbed or wick into the original.
- Consider adhesive delivery techniques, flow, penetration, and molecule size before choosing an adhesive or application method.
- Historic photographic image layers may be weakened from age and situational damage. Consider the desired functional strength necessary of both adhesive and support material for any repair.
- Create a clean, reduced-dust environment in which to work. Many photographic material images are small. Small dust particles can be trapped within a mend, or scratch a surface while working.
- For sensitive photographic materials, consider wearing dust-free gloves. If necessary the gloves can be modified so only a few fingers and thumbs are exposed.
- Determine the appropriate degree of loss compensation based on the history and intended use of the photograph.
Effects of Mending, Repairing, and Filling on Photographic Materials
- Strengthen and stabilize the object for safe handling and display.
- Restore aesthetic continuity of the object for viewing.
- Stabilize current damage and decrease the likelihood of continued loss/damage.
- Photographic Grade
- Consider appropriate bloom strength and concentration
- Usually used warm
- Can work well for relaxing and setting down lifting areas of emulsion around a crease/tear
Wheat Starch Paste
- good option when strength is required; stronger than cellulose ethers
- Methyl cellulose
- not as "wet" as paste, and may be a safer choice for moisture sensitive photographs
- gives a longer working time and better "slip" than wheat starch paste
- Can be used in combination with wheat starch paste to get strength and slip
- Hydroxypropyl cellulose
- Sodium Carboxymethylcellulose (SCMC)
- a longer chain molecule than Methylcellulose and therefore gives a stronger bond than Methylcellulose (Baker 2007)
- Klucel G
- Can be used in ethanol for objects that are sensitive to water
- Relatively weak adhesive
- May discolor over time
- Klucel M
- Similar to Klucel G, but stronger adhesive due to increased chain length
Plextol B 500
- Acrylate resin dispersion with water
- Can be used as heat-set when dry
- Comes in three different chain lengths with increasing strength: 50, 200 and 500
- Soluble in water and polar solvents
- Highly modifiable by combining chain lengths and solvent combinations
- Will yellow over time, especially Aquazol 50
Equipment and Materials: Considerations
- Round or flat shaped brushes are both useful shapes for adhesive applications.
- Brown synthetic hair brushes will show white and clear adhesives easier on the brush while working.
- Natural fiber brushes are best for using solvent-based adhesives. Test brush hairs against any organic solvents before working.
- Watercolor brushes have short handles, so are ideal for close work.
- Brush handles can be further shortened for work under the microscope.
- For large and over-size photographic materials, photographic and craft sponge brushes, commercial hardware paint sponges, and flat sponge-brushes are useful for applying adhesives evenly to large areas.
Ultrasonic delivery systems and nebulizers
- Standardized sizes of polyester webbing, blotters, and platens for use in flattening and drying can be pre-assembled for large jobs. Add desired weight amount.
Heat irons and warming plates
- For synthetic adhesives, the use of heating irons and warming plates may be necessary.
- Keep temperatures as low as possible to activate the adhesive.
- Apply heat through another material, such as silicone release paper. Wrapping the flathead of the heating tool saves time, but needs to be monitored closely for any debris it might attract.
- Prepare cooling/curing materials (glass and metal platens) for immediate flattening.
- Clean, bare hands are usually suitable. When mending sensitive photographic materials, however, sometimes gloves are preferred. Stretchy, lintless cotton photographic gloves with the forefinger and thumbs cut away are often ideal.
- Remoistenable tissue
- Heat-set tissue
- Plumber's tape
- Magic Rub eraser inside a nylon stocking
Fillers and Additives
Microcellulose fibers with starch paste, methylcellulose, fish glue, Aquazol, or resins
- (+glass balloons, silicas, barium sulfate, titanium pigments, or kaolin)
Aquazol (various mw) + inerts/dry pigments
- Flugger Acrylic Spackle (Denmark)
- Can be imprinted and burnished
- Modostuc Spackle (Italy)
- Crawford's Vinyl Spackling Paste (US)
- Beckers Latex Spackle (Sweden)
BEVA Gesso P
- Solvent based, BEVA adhesive
- Untoased or toasted
- With glass balloons
- With pigments
Useful Techniques for Photographic Materials
- For repairing cracking within prints, see the in-depth discussion under Consolidation and Flattening of Cracks.
- For materials that readily swell when you wish to use an aqueous adhesive, blotters can be dessicated in a microwave or warmed on a warming plate to pull out moisture prior to application against aqueous mend (Hugh Phibbs technique). Dessicated blotters pull out moisture more rapidly and reduce swelling and potential distortion than routine, room-temperature blotters.
- Using a flat small-headed tacking iron on low heat can help set mends. Proceed cautiously as melting or rippling of the photographic material can occur if the temperature is too high or application time too long.
- Overfill at center to counteract shrinkage and avoid forming a concave meniscus when dry; however, premature smoothing will remove fill material from the damp center.
- Can dilute filling mixtures and dot on with a brush.
Mending A Fiber-Based Photograph
- Set up a work station with the photograph on non-woven polyester and blotter, or appropriate custom support.
- Gather all tools needed for the entire process before beginning: adhesive and a variety of brushes, water and/or solvent, spatula, tweezers, burnishing tool, squares of non-woven polyester and blotter, glass or acrylic plates and weights.
- Align the tear. Use small tools and gloves as necessary to bring the edges of the tear or break into alignment. Have an awareness of how the tear will fit together along its full length before applying any adhesive. Once the tear is aligned, weight both sides in place, and use magnification to tuck in any protruding paper fibers. Fine brushes, dental tools, and soft fine-tipped tweezers are especially good for this task.
- Begin applying adhesive to the exposed paper fibers along the tear. Apply adhesive to the underside of an overhanging flap, or the surface of the bottom ledge, taking care not to get any on the photograph surface. If working in sections, begin at the interior of the photograph and work outwards to the edge.
- Double check the tear for any protruding paper fibers and tuck them back into the seam. Do this with extreme care as the binder will be very soft from the adhesive and easily damaged.
- Firmly burnish the mended section through a piece of non-woven polyester and blotter, then place under a glass plate and weights until fully dry.
- Once the mend had dried it can be reinforced from the verso using thin strips of Japanese paper adhered with wheat starch paste or methylcellulose.
Cellulose Powder Fills
- Solka-flok is one brand of cellulose powder; 300 is the finest grade, 200 and 100 are more coarse.
- Cellulose powder is mixed with a solution of methylcellulose to produce a paste
- Cellulose powder can be "toasted" in a beaker on a hot plate to achieve various off-white and brown tones. This should be done with the dry powder, before mixing with methylcellulose. Wash after toasting to decrease the smell, sieve through Hollytex, let dry, and then grind in a mortar and pestle. You can break up any clumps on a micromesh.
- The paste can be pressed into small holes and losses with a micro spatula, and the surface smoothed with a Teflon tool
- Best for small losses where internal strength of the fill is not a concern
Toned Paper Fills
- Japanese papers or photo-safe Western papers may be dyed, painted, and/or finished to resemble a photographic surface, and used to fill large areas of loss
- watercolors, colored pencil, and acrylic paints can all be used to impart color
- watercolors: good for dyeing very absorbent papers
- acrylics: work best when brush applied or smoothed with a brayer through Mylar
- colored pencil: good for fine lines and detail
- various surfacing materials can be used to adjust the gloss of toned papers:
- acrylic gloss medium: applied thickly to the paper and placed face-down on Mylar or silicone-release Mylar, smoothed with a brayer, and allowed to dry against the Mylar
- gum Arabic: when brush applied, creates a high-gloss surface with fine cracking an imperfections, closely resembling an aged albumen surface
- gelatin(e): can be painted on for very subtle surface effects, or thick applications can be dried against Mylar to form a glossy film.
- acrylic paints and gloss medium dried against Mylar will produce a glossier surface than will gelatin
- iridescent paints or pigments: when applied over toned layers can resemble mirrored photographic surfaces
Digitally Printed Fills
- Victoria Binder has published on a method for creating fills in Photoshop using a scan of the original photograph, and then using an inkjet printer to print out fills in a variety of tones on a paper with the desired gloss (fig. 1; Binder 2013).
Baker, Catherine. "Sodium Carboxymethylcellulose (SCMC) Re-evaluated for Paper, Book, Papyrus, and Parchment Conservation." Book & Paper Group Annual 27. Washington D.C.: American Institute for Conservation, 2007.
Bernstein, J., D. Evans, and V. Binder. 2018. "Compensation for loss in the conservation of photographic materials workshop manual." Revised and updated. George Eastman House, Rochester, NY.
Binder, Victoria. "Digital Fills for Photographs with Glossy Surfaces." Topics in Photographic Preservation 15. Washington D.C.: American Institute for Conservation, 2013. 363-370.