JAIC 1997, Volume 36, Number 3, Article 8 (pp. 253 to 261)
JAIC online
Journal of the American Institute for Conservation
JAIC 1997, Volume 36, Number 3, Article 8 (pp. 253 to 261)



ABSTRACT—Two housing solutions were devised by the author: one for unique and delicate art objects made from brittle, dried leaves and another for a group of 12 large maps. The housing designed for the “leaf portraits” uses a standard print box and a deep double sink with a friction mount as a base to secure and protect the leaves. The map housing is an oversize sink mat made of Coroplast polyflute and Fome-cor. Difficulties with adhesion to the Coroplast are briefly discussed, and a detailed construction outline is given.

TITRE—Deux Coffrets: La modification d'une boîte standard et la construction d'un coffret aux grandes dimensions. RÉSUMÉ—Deux types de coffrets ont été conçus par l'auteur: le premier pour les objets d'art uniques et délicats fabriqués en feuilles séchées et fragiles; le deuxième pour un ensemble de 12 grandes cartes. Le coffret pour les “portraits en feuille” utilise un coffret standard ainsi qu'une double dépression avec une monture spéciale qui sert de base pour tenir et protéger les feuilles. Le coffret des cartes consiste en un très grand coffret rembourré fabriqué avec du Coroplaste polyflute et du Fome-cor. L'article examine les difficultés liées à l'adhérence au Coroplast et donne un plan détaillé de la procédure de construction.

TÍTULO—Dos sistemas para almacenamiento: Modificando una caja estandard y construcciíon de un passepartout hundido de tamaño extra grande. RESUMEN—Fueron ideadas por el autor dos soluciones de almacenamiento: una para objetos de arte únicos y delicados hechos de hojas secas y quebradizas, y otra para un grupo de 12 mapas grandes. El sistema de almacenamiento diseñado para los “retratos de la hoja” utiliza una caja estándard para grabados y un sistema de passepartout doble hundido con montura de fricción como base asegurar y proteger las hojas. El sistema de almacenamiento para los mapas es un passepartout hundido de tamaño extra grande hecho de Coroplast polyflute y de Fome-cor. Las dificultades con la adhesión al Coroplast son discutidas brevemente y se da un guía detellada de la construcción.


The holdings of the Harry Ransom Humanities Research Center, in addition to book and archival collections that receive traditional housings, include three-dimensional objects and artworks. The Conservation Department frequently designs and constructs unique housings for these objects. The Swanson “leaf portraits” were too brittle for hinging, foldering, or polyester encapsulation; a modified standard print box with a friction mount was made to house these items. Of the 12 oversize maps in the H. P. Kraus Collection, 8 were flat and 4 were on stretchers; all were inadequately housed. Traditionally such items would be stored in flat files or encapsulated in polyester. These maps were too large for available flat files and were thought to be too heavy and too delicate for hanging encapsulation. In addition, safe transportation of the maps from one floor of the library to another by elevator was a necessary consideration. The following details the design and construction of these housings.


Housing two portraits of Gloria Swanson made from large plant leaves posed several interesting challenges. The image is formed in each leaf by the removal of material between the vein structures (fig. 1). These extremely fragile and desiccated artifacts could not be allowed to move within the housing and needed more support than simple encapsulation would provide. The curator requested that they not be restrained by any strap or covering material that would obstruct visual examination by the researcher but agreed to restrict examination to the recto only.

Fig. 1. Artist unknown, leaf portraits of Gloria Swanson, n.d., unidentified plant material, 13 × 26 cm. each, Golria Swanson Papers, Series VII, Subseries A, Art Work, Folder A2

A 1 in. deep double sink was constructed of four-ply mat board within a standard print box. The bottoms of the sinks were covered with Japanese paper (okawara), which was lightly sanded to raise a nap forming a friction mount. The leaves, once positioned in the sinks, are gently but adequately restrained. If necessary, the leaves can be carefully lifted out by a conservator. A removable sheet of four-ply mat board was laid across the top of the mat to reduce disturbance of the leaves by the partial vacuum created by lifting the box lid. Finger holes cut in this sheet allow it to be easily removed and prevent it from creating the same vacuum effect, when raised, as the lid. The original housing, a paper folder, was put in a 20 point lignin-free tuxedo wrapper attached to the four-ply sheet. Velcro tabs attached to the lid and bottom of the box secure the lid when the box is closed.

This housing was made 2 years ago, and the objects have been viewed frequently since. The friction mount allows the housing to be moved, jostled, even tilted, without any disturbance of the leaves. The leaves have been removed from the housing and replaced without mishap. The basic design of the sinks within the standard box could easily be modified to house three-dimensional objects.

The estimated construction time for this project is 5 hours. Project supervision and design were by Patricia Ingram. Housing construction and design were by Margaret Brown and Ethel Hellman.


The 12 oversize maps in the H. P. Kraus Collection are all approximately 42 × 58 in. Most have several layers of paper and linings and are quite stiff; some are cockled. All have many previous mends and fills and are generally in a delicate condition. The housing described below protects the maps when stored and enables them to be safely carried.

The housing is a large sink mat with a cover hinged along one long edge. The mat forming the sink is constructed of Fome-cor. Our housings are 52 × 68 in., making the mat surround about 5 in. wide. The wide Fome-cor mat gives rigidity to the housing as well as creating the sink to protect the map. A laminate of two layers of Fome-cor was sufficient for eight of the maps. The remaining four are on wooden stretchers and required mats up to 1½ in. deep; these were constructed of layers of Fome-cor and Tycore. The housing is held closed along the three open sides by linen ties. It is designed to lie flat in storage and when necessary to be carried by two people, upright with the hinge edge down. The map can be examined without removing it from the housing by leaning the cover down from a table or up against a wall, or folding it underneath the housing. As the versos of the maps generally contain no images or text, a photograph of the verso of each map is mounted inside the housing to discourage unnecessary handling of the map. The maps are not attached to the housing.

Coroplast, a corrugated polypropylene copolymer sheet, was chosen for the boards as it is inert, strong, lightweight, and inexpensive. Three disadvantages of this material are its relatively low melting point (230°F), the possibility of infestation in the small spaces of the corrugations, and the difficulty of attaching it to other materials. Alternative but more expensive materials include Gatorfoam and Tycore.

In three different instances it was necessary to attach other materials to the Coroplast. Ten point lignin-free board or cover weight paper was attached to the bottom board as a liner for the map to rest on. Even though the Coroplast we used contained an anti-static agent, there was still evidence of a static charge on the sheet and it was felt that a liner was necessary to protect the map. Rhoplex N-580 was used for this bond with qualified results. As the board was flexed, the lignin-free liner detached from the Coroplast and developed bubbles. If the entire housing were made at one time, flexing could be avoided. Using spot or edge adhesion might also avoid this problem. A spine hinge of paper-backed, cotton-linen book cloth was adhered to both boards with Rhoplex, and there were no problems with this bond when the Coroplast was prepared by sanding. There were many unsuccessful attempts to adhere the Fome-cor mats to the Coroplast. When Rhoplex was used and the board was flexed, the rigid Fome-cor separated from the Coroplast. BEVA (Berger ethylene vinyl acetate) was also tried, but solvent fumes were a problem. Hot-melt glue was suggested by the manufacturer, but it was difficult to apply a thin coat quickly over the large expanse of board. We were also concerned about the long-term stability of the hot-melt glue. Sewing the mats down with nylon monofilament was considered. Finally it was decided to attach the first of the two or more layers of Fome-cor to the Coroplast with album-type screw posts. Additional layers of Fome-cor were adhered with PVA [poly(vinyl acetate)], covering the screw posts.

The maps have been transported in these housings many times and shift very little as they are carried. Simple loop handles would make carrying easier.

This project was completed over a period of two years, working one afternoon a week. The project was designed by Patricia Ingram and work was supervised by staff, including Ingram and George Leake, but often done by inexperienced volunteers. The following instructions were written to reduce confusion resulting from such a fragmented schedule. The design is simply an ordinary sink mat enlarged, but when even a simple structure is enlarged, materials behave differently and procedure becomes even more important. Given the investment in materials and time an oversize housing project requires, one seeks to limit experimentation, and having a chronology of construction steps to begin with and improve upon can be useful.


  1. Make an exact paper template of each map. Using the template instead of the map during the construction of the housing reduces damage to the map caused by handling.
  2. Adhere a lignin-free liner to the Coroplast. If the Coroplast is not precut, cut an upper and lower board to desired size with a utility knife.Cut a rectangular liner of 10 point lignin-free board or cover weight paper to a size several inches larger than the map template.Center the liner on one of the Coroplast boards, and outline the corners of the liner with pencil on the Coroplast to aid in placing the glued surface down accurately (fig. 2).Apply Rhoplex to the underside of the liner, and adhere to the Coroplast board. Rhoplex is very sticky and will bond on contact; avoid allowing the free end of the liner to touch the Coroplast.
  3. Seal or fill the ends of the corrugated boards with PVA or hot-melt glue to discourage infestation.
  4. Punch holes, and secure ties. Measure and mark positions for ties on three sides of the Coroplast boards. Be generous in deciding the number of ties, as snug closure is essential for safe transportation (fig. 3).Use a chisel and hammer to make slits in the Coroplast for each tie. Slits should be at least ½ in. from and parallel to the edge.Pass a 12 in. length of linen tape through each slit and sew as illustrated, creating a snug loop attachment to the Coroplast. Cut the end of the tape at an angle to prevent fraying (fig. 4).
  5. Sand the spine edges of the Coroplast to prepare the surface for attachment of the inner and outer hinges. Draw a pencil line 3½ in. from the spine edge (the edge with no ties) on the top and bottom surfaces of each Coroplast board. This line marks off four areas where adhesive will be applied to attach the hinges.Use an electric sander to sand these areas, roughing up the smooth surface of the Coroplast.
  6. Attach the outer hinge. Cut a strip of book cloth with the grain long. This strip will be the outer hinge and should be 8 in. longer than the spine edge of the Coroplast. The width of the strip should be 7 in. plus the thickness of the spine. The spine thickness is equal to the total thickness of the Fome-cor mats plus two pieces of Coroplast plus 4 pieces of book cloth plus 1 piece of book cloth for ease.Set dividers to the spine thickness.Fold the hinge in half at each end and pinch it, creating two small creases as shown in figure 5.Using the crease in the end as a guide, mark the thickness of the spine with two pencil marks in the center of each end of the hinge, as shown in figure 5.Draw two pencil lines along the length of the hinge connecting the pencil marks and outlining the spine area of the hinge.Position the two pieces of Coroplast and the hinge, paper side up, as shown in figure 6.Apply Rhoplex to the hinge using rollers.Move the Coroplast covers onto the hinge, aligning the edge of the Coroplast with the nearest pencil mark and leaving an equal cloth turn-in at each end of the spine. Press down on the Coroplast to ensure adhesion of the hinge.Turn in the ends of the cloth hinge, adhering it to the upper surface of the Coroplast. Pull the sides of this turn-in toward the center, gathering extra cloth in the spine area. Bone the cloth down onto the Coroplast.Use scissors to make two relief cuts in the spine area of each turn-in, as shown in figure 7. Do not cut all the way to the fold of the cloth. There should be at least ½ in. of uncut material at the folded edge of the cloth. Bone down the cloth in the spine area.Close the housing, and bone down the cloth on both outer surfaces.
  7. Attach the inner hinge. Cut another hinge of book cloth with the grain long. This strip will be the inner hinge and should be ½ in. shorter than the spine edge of the Coroplast. The width is the same as that of the outer hinge.Crease the ends of the hinge, and outline the spine area of the hinge, as described in steps 6 c–e.Make two folds along the pencil lines with the paper side of the cloth to the outside, as shown in figure 8.With the housing open, use a piece of scrap board to apply a generous amount of adhesive to the paper surface of the outside hinge between the edges of the Coroplast.Use a bone folder with a rounded edge and your hands to place the folded inner hinge, paper side down, onto the glued area. This is best done one fold at a time, by pinching the cloth of the inner hinge together at one fold and setting that fold in place at the edge of the Coroplast. Bone this fold down on the cloth side, working across the spine area to the other fold (see fig. 9). The inside hinge tends to pull away from the edges as it is adhered (see fig. 10).Once the spine is adhered, fold both hinge flaps to one side, place scrap paper between the flaps, and apply adhesive to the paper surface now exposed. Adhere this cloth to the adjacent sanded area of Coroplast, and bone it down. Repeat for the other hinge flap.Remove any excess Rhoplex with a vinyl eraser.
  8. Cut Fome-cor mats. If the shorter dimension of the map exceeds 40 in., the Fome-cor mat will have to be pieced. The map should fit in the sink with as little extra room as possible to minimize shifting of the map when the housing must be turned on edge for transporting. The surround of the mat should be wide enough to give rigidity to the housing. Cut a Fome-cor sheet to the size of the base of the housing using a utility knife.Center the map template on the Fome-cor, and secure with weights.Long straightedges are useful in creating a rectangular window around the irregularly shaped maps. Once the appropriate window is achieved, mark the Fome-cor at the corners of the window. We allowed 3⅙ in. leeway around the map.To avoid future confusion, label each layer of the Fome-cor mat on the edge adjacent to the hinge with each of the following: north;upper mat or lower mat (if there are more than two layers, label accordingly);top or bottom surface (keeping the orientation of each layer the same in gluing as in cutting helps in achieving a clean window).Cut out the sink using a utility knife with a fresh blade. Make clean, vertical cuts. Polystyrene foam dulls blades quickly, and the snap-off blade of the Olfa knife was convenient here.Check the fit with the map template.Cut another layer of Fome-cor to the size of the base of the housing, and place this layer beneath the cut mat. If mats are pieced, stagger the joins, as shown in figure 11.Trace the inside edge of the cut mat onto the Fome-cor beneath it with a pencil. Pencil marks on this edge will later be covered with paper.Cut lower mat pieces, and label as described in step 8d. If there are more than two layers of Fome-cor, use the same mat as the pattern for all the others.
  9. Attach the lower Fome-cor mat to the Coroplast with screw posts. Position the lower Fome-cor mat on the Coroplast base, and secure with weights.Cut a jig for quick marking of holes. Use the jig to mark locations for holes at least ½ in. from all edges as shown in figure 12. We put a screw post every 6 in., but fewer could be used. Where the ends of pieced mats join, put holes at all corners.Punch with an awl or drill holes through the Fome-cor and the Coroplast at the same time. Begin by making a few anchor holes and securing the Fome-cor to the Coroplast with screw posts, then make the remaining holes. Insert the larger, hollow screw posts first through the Coroplast from below, then up through the Fome-cor. Insert the smaller screw posts from the top, down into the Fome-cor and the hollow part of the fastener. Tighten the screw posts until the slotted heads are recessed enough to allow the second layer of Fome-cor to lie flat.
  10. Adhere the upper Fome-cor mat to the lower one using PVA.
  11. Apply a paper strip to the inside edge of the Fome-cor sink mat. This strip protects the map from the abrasive edge of the cut foam. Cut several long strips of acid-free cover weight paper, enough to go around the window of the mat. The width of the strips is equal to a little less than the depth of the completed mat (measured at the inside). The grain should be long.Apply thick PVA or PVA-paste mix to one strip and begin adhering this first strip at one corner of the sink mat window as shown in figure 13. After the strip is in place, work it for several minutes with your hands and/or a bone folder. A Teflon folder works particularly well here.Repeat for each strip until the entire inside edge of the sink is covered. The ends of the strips can be butted to each other or slightly overlapped.
  12. Cover any joins in the top mat with strips of acid-free paper.
  13. Adhere labels. We adhered a photograph of the map's verso to the underside of the cover.
  14. Allow adhesive to cure for a week with the housing open.

Fig. 2. Coroplast board with liner attached

Fig. 3. Ties attached on three sides of Coroplast boards

Fig. 4. Attachment of linen ties

Fig. 5. End crease in hinge with spine thickness marked

Fig. 6. Positioning of Coroplast and hinge

Fig. 7. Relief cuts in turn-ins of outer hinge

Fig. 8. Folded inner hinge

Fig. 9. Inner hinge - correct

Fig. 10. Inner hinge - incorrect

Fig. 11. Staggered joins in mat

Fig. 12. Lower Fome-cor mat with screw holes

Fig. 13. Paper strip adhered to inside of sink


The author would like to acknowledge the helpful insight and opinions of her colleagues at the Humanities Research Center as well as the contribution of Elizabeth Dube to the preliminary stages of this paper. The figures illustrating the Kraus instructions were created by Liz Dube.


Standard print box

Metal Edge West, 2721 E. 45th St., Los Angeles, Calif. 90058, (800) 862-2228

Four-ply mat board 100% rag, acid-free museum quality mounting board

University Products, P.O. Box 101, Holyoke, Mass. 01041, (800) 628-1912

Heavy Japanese paper (Okawara)

Aiko's Art Materials, 3347 N. Clark, Chicago, Ill. 60657, (312) 404-5600

20 pt. lignin-free board and Jade 405 PVA

Conservation Resources, 8000-H Forbes Pl., Springfield, Va. 22151, (800) 634-6932

Estimated material cost: $27. The Humanities Research Center purchases many materials in large quantities, a system that reduces the unit price; this estimated cost of one housing is based on our cost.


Coroplast corrugated plastic sheets, precut, 4 mil.; 10 pt. lignin-free board or archival cover weight paper; Monsanto acid-free Fome-cor, ⅜ in. thickness; paper backed cotton-linen book cloth; metal album-type screw posts; ⅝ in. linen tape; linen thread; adhesives: poly(vinyl acetate); Rhoplex N-580, wheat starch paste (50:50 mix with PVA); tools: sewing needle, scissors, bone folder, Teflon folder, long metal straightedges, disposable glue rollers and trays (we used small, 4 in. rollers and trays and just let the Rhoplex dry on them; they can be used quite a few times even with this abuse), pressing boards, lead weights, ⅝ in. chisel, electric sander and medium-coarse sandpaper, awl or electric drill and ¼ in. drill bit, Olfa utility knife (this particular knife is very easy to use), vinyl eraser.


Coroplast 4 mil.

Coroplast Inc., 4501 Spring Valley, Dallas, Tex. 75244, (800) 666-2241

10 pt. lignin-free board

University Products, P.O. Box 101, Holyoke, Mass. 01041, (800) 628-1912

Monsanto acid-free Fome-cor ⅜ in. thick

M & M Dist., P.O. Box 727, Freehold, N.J. 07728, (800) 526-2302

Mohawk Superfine 80 lb. cover weight paper

Monarch Paper, P.O. Box 18568, Austin, Tex. 78760, (512) 443-7112

Cotlin Van Heek Scholco (Half-linen) book cloth

Ecological Fibers, 40 Pioneer Industrial Dr., Lunenburg, Mass. 01462-1699, (508) 537-0003

metal screw posts

local hardware store or office supply

Olfa utility knife

Daniel Smith, 4130 First Ave. S., Seattle, Wash. 98134, (800) 426-6740

Jade 405 PVA and linen sewing tape

Talas, 213 W. 35th St., New York, N.Y. 10001-1996, (212) 736-7744

Rhoplex N-580

Conservation Support Systems, 924 W. Pedregosa St., Santa Barbara, Calif. 93101-4622, (800) 482-6299

Estimated material cost: $100 for each of the housings with two layers of Fome-cor. The Humanities Research Center purchases many materials in large quantities, a system that reduces the unit price. This estimated cost of one housing is based on our cost.


PATRICIA INGRAM received a B.A. in studio art from the University of Texas at Austin in 1978. She began her conservation training in the Conservation Department of the Harry Ransom Humanities Research Center and has worked there as a book conservator since 1990. She enjoys the three-dimensional problem solving associated with housing in general and oversized housing in particular. Address: Conservation Department, HRHRC, University of Texas at Austin, P.O. Drawer 7219, Austin, Texas 78713-7219; p.ingram@mail.utexas.edu

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Copyright © 1997 American Institute for Conservation of Historic and Artistic Works