B08_Att_3_Conservation_and_Treatment_Report_-_Main_Lobby.pdf

CONSERVATION TREATMENT REPORT

AQUATIC PARK BATHHOUSE MURAL BY HILAIRE HILER, 1939

San Francisco Maritime National Historical Park Aquatic Park Bathhouse Building

900 Beach Street, San Francisco, California prepared for the National Park Service

San Francisco, California

CONSERVATION TREATMENT REPORT:

AQUA TIC PARK BATHHOUSE MURAL BY HILAIRE HILER

TABLE OF CONTENTS

CONSERVATION TREATMENT REPORT

Background Consenrators. •• . . • . . . . . . . . •. . . • . . . . • .•• . ••• . . ••• . •••••. ••••• ••• . .. • . . . . . . •. •• . . . . . ••••• •••• 3 Sequence of the Treatment Documentation The Numbering System of Photographs ~i~llti11g Technical References to the Mural in Historical Documents

CONDITION OF THE MURAL

Support ............... ,., j)ri111i11g J>ai11t ~il111

F'ac:lin~······················································································ 10 Overpaints .................. ,.,........................................................... ...• 11 Surface coatings

TREATMENT:

<:leani11g Signature Found Stabilization of Flaking Paint \'arnislai11g Reattaching Canvas Repair at center wall, East and West Compensation of losses In painting Ceilings of Window Bays

APPENDIX

I. Keys to Numbering System of Photographs II. Technical Analysis of Varnish Coating III. Technical Analysis of blue background paint

CONSERVATION TREATMENT REPORT:

AQUA TIC PARK BA TIIHOUSE MURALS

BY HILAIRE HILER

WITH TIIE THEME OF THE LOST CONTINENTS

OF ATLANTIS AND MU

2"d floor, Main Lobby, 900 Beach Street, San Francisco, California 2009-2010

Background:

This treatment report describes painting conservation and restoration work provided for the National Park Service, over a period of two years. The location is the main lobby mural on the second floor (main entrance) to the Aquatic Park Bathhouse, located at 900 Beach Street, San Francisco, also known as the Maritime Museum, a National Historic Park site.

A WPA project in 1938-39, the lobby mural was painted by Hilaire Hiler who was chiefly responsible for the overalJ decoration of the building. As artist and color theorist, l{ ~"t.i)

Hiler was noted for his books on color, and for his interest in the psychology of color. In addition to the lobby mural of undersea life, he painted a color wheel on the ceiling, and gray scale on the walls of the west end room of the Bathhouse Building called the "8ay·1iew Room" or "Prismatarium." Numerous other artists worked in the building under Hiler, including Richard Ayre and Charles Nunnemaker, whose works are individually signed; others are unrecognized, unnamed artist-assistants, who worked alongside them.

The mural in the main lobby is Hiler' s largest public work, and is sometimes titled "Undersea Life" or "The Lost Continents of Atlantis and Mu." Begun in 1938, the mural was nearly finished in 1939, when a proposed change of building use by the City of San Francisco spawned artist protests and their subsequent walk-out work strike.

World War II ensued, and Hiler did not return until ten years later to finish some of the interrupted work, and to possibly make repairs. A few empty areas and unfinished forms in the mural suggest Hiler never entirely completed the piece, or he changed his mind and abbreviated the design. WPA photographs taken during the first painting campaign are excellent sources for information regarding the set up of the workspace and progress over time. Photographs suggest at least two assistants contributed to the painting of the large color fields of the background, and possibly some of the well-blended meticulous details in the lower register of the mural.

Prior to the treatment described in this report, the conservator, subcontracted with the architectural firm in 2008 the treatment of a portion of the south wall. That report was submitted to the NPS through their auspices. The work entailed the extensive restoration of a small part of the mural, limited to the window bays of the south wall. Treatment of those spaces necessarily predated the larger project of the room interior, as the work coordinated closely with the architectural needs of wall repair/window replacement. The deterioration of the mural at the window bays was also considerably more advanced and urgent than that of the remaining walls. The severe southern exposure to light, heat, and water infiltration caused the window bays to deteriorate in ways not common to the rest of the room.

South Wall Window Bay 2008

Before Treatment After Treatment

Conservation Treatment Report 2009-2010 The Aquatic Park Bathhouse Murals by Hilaire Hiler, 1939

The conservation treatment of the main body of lobby mural includes cleaning the surface of considerable soot and debris, ameliorating areas of moisture damage, and filling structural losses to the canvas and wall due to building settlement/cracking, and from careless installation of museum exhibits and/or signs. Other remedial work included removing pressure sensitive tape, embedded plastic curtain anchors, reattaching localized areas of lifted canvas and flaking paint, followed by varnishing and inpainting numerous scratches, gouges, and stains.

Sequence of the Treatment:

The room was divided into discreet areas to facilitate the flow of the public into the room, and to reduce on-site work into manageable portions. A period of several months lapsed between each phase of conservation work. The order of completion was the following:

• The south wall proper (excluding the south wall window bays).

• The north wall and triangular sections on the sides of the stairs.

• The structural work on the east and west walls, and east wall cleaning.

• Completion of all work on east and west walls.

Documentation:

The mural was documented in sections, with detailed digital color images and black and white film, before and after treatment. The "during treatment" stage was illustrated with representative detail photographs. The high resolution digital images were made using a Nikon DlOO professional 10 megapixel SLR camera and a Kodak 8 megapixel automatic focus camera as backup. Images were copied to gold CDs, which accompany this report.

A color scale and gray scale were included in the overall document photographs; detail photographs do not have the color scales, as they could not accommodate the size of the scale. The black and white images were created with 400 ASA Ilford and Fugi film, with a Nikon Nikormat SLR camera; 4x6 prints were provided in archival sleeves.

The Numbering System of Photographs:

Documentary photographs are numbered within the image with numerical and letter designations.

In every case (with the exception of the south wall) there is a letter corresponding to the cardinal point on the compass (N-north, E-east, and W-west) referring to the location of the wall.

Each wall is divided into a number of vertical sections from left to right. The east and west walls are the same size, so they each divide into five equal sections of approximately 57" wide. Each section is divided further into three parts horizontally (44"

Conservation Treatment Report 2009-2010 3 high by 5T' wide), and these are numbered la, lb, le, from top to bottom. Section I (la, I b, 1 c) is followed by the next section to the right, which is 2a, 2b, 2c, etc., starting at the top, continuing down then to the next section to the right, which is 3a, 3b, 3c

The north and south walls are longer than east and west, and are divided into smaller sections due to the windows. Larger sections flank the entry doors. Undercut areas around the doorway continue down from the top of the wall; therefore, some of the sections have designations from "a" to "e." The small spaces above the window openings are given a hybrid number (such as 1-2, or 5-6) showing the numbers of the wall sections they come between. The north wall has 21 sections, and the south wan has 17 sections. AU walls are numbered from upper left to lower right across the length of the entire wall. A diagram of these configurations is included in this report.

Each photograph also contains a letter on a magnetic strip with the designation "A," meaning Before Treatment, or "D," meaning After Treatment. In-process treatment photographs do not have a letter designation.

Lighting:

By far, the most problematic element of the documentation surrounds the complex lighting of the interior of the room. Incandescent lamps are installed at the top of the wall with 2700 degree Kelvin temperature; these were turned off and on in various circumstances, as needed. The room is otherwise dependant upon natural daylight, which is very mixed and changeable. Daylight can range widely between 3400-12,000 degrees Kelvin. Clouds and the shift of sunlight during the day make the proper white balance, quantity of light, and direction of light highly unreliable. These variables and working from mechanical scissors lifts with attached banks of fluorescent daylight bulbs (F32T8/excella from SLI Lighting) resulted in some of the colors in the photographs to not always remain true. Various white balance settings on the Nikon camera were tried with variable results. Some of the photographs were taken with black-out shades over the windows, to help control the results. Specular light ("hot spots") from lighting sources also contributed to the problem.

The digital color images included with the report have not been altered. By using the color scale in the images, more consistent color comparison before and after treatment can be achieved with computer software. To illustrate the on-site problem, the following chart is offered:

Conservation Treatment Report 2009-2010 4 The Aquatic Park Bathhouse Mura/,\· by Hilaire Hiler, 1939

Degrees Type of Indoor (3200k) Outdoor (5500k) Kelvin Light Source Color Balance Color Balance 1700-1800K Match Flame '@ii !A41J 1850-1930K Candle Ffame 2000-3000K Sun· At Sunrise or Sunset 2500-2900K Household Tunasten Bulbs 3000K Tungsten la_rrtp_ 500W-1k 3200-3500K Quartz Lights 3200-7500K Fluorescent Lights 3275K Tungsten Lamp 2k · 33BOK Tun9sten Lamp Sk, 10k 5000-5400K Sun; Direct at Noon 5500-6500K Day_light (Sun + Sky) 5500-6500K Sun: through clouds/haze . _ 6000-7500K Skv: Overcast 6500K RGB Monitor (White Pt ) I f 7000-SOOOK Outdoor Shade Areas 8000-10000KSky; Partl~ Cloudy

Based on information from the book [Qjgit;;iJ]_Lightin_g & R_e_riq~rjng Chart and colors (c)2003 Jeremy Birn for ~.~QB.end~!'.....C.J:!!Il

The above diagram shows some of the possible conditions under which lighting had to be adjusted. Lighting difficulties were encountered not only in photography, but while inpainting.

Technical References to the Mural in Historical Documents:

Archival references to materials used in the fabrication of the murals were few, and some very sketchy. Some have proved to be inaccurate hearsay. References were provided for the conservators, as they became available, through the librarian of the Maritime Museum in Building E, Fort Mason. Of most benefit was the identification of certain materials, including the following:

• Extensive use of the newly manufactured blue colorant (1936) called "thalo" or "monastral" blue.

• Use of "stearates" in the varnish (found to be incorrect; silica was used).

• An artist friend's account of Hiler achieving a "semi matte surface" to the mural

(the paint surface, as found, was mostly satin, slightly shinier than semi matte, or in some areas, glossy, reflecting considerable light).

• The artist's statement that his medium was a "modification" of the Gambier-Parry spirit fresco medium. This comment did not describe the actual materials used, or how they may have been combined. Further, this reference did not explain the wide variation of solubility of the mural, nor contribute understanding of handling problems. The Gambier-Parry method uses pigment, oil of spike (lavender) in oil, copal varnish, and wax. A more precise explanation of Hiler's medium is unknown at this time, although some material analysis of the paint and varnish are included in this report.

• WPA photographs of many gallon cans of (probably commercial, Fuller brand) paint were positioned near the mural. Whether part of the mural was commercial

Conservation Treatment Report 2009-2010 5 paint, and other parts "spirit fresco," or whether the paints were only used for the ceiling is still unknown.

United Slala. Wort. Proirna Admmis1ntl01L Aq11&hc Porlc- in...nor Vi<WS. San Fr.w:ilco, Ca..

May 11. l9JS !>hiralt la Lobby, F«mcrlyAll.3MOln. rhooop. No: N-19i9. Sao franc:it<o Maritime Natlcnal llitlorical Parle. l'83-03S 1•7p. COl'Yrislic Pub iC Domain.

CONDITION OF THE MURAL

Support:

Numerous damages common to the window bays are also found in the lobby proper.

The support fabric (cotton) on which the mural is painted seems to be the same throughout, as is the adhesive between the canvas and plaster (water soluble glue/paste).

There are many small separations between the canvas and the walls. By far, the greatest numbers of these occur on the north and south exterior walls, especially on days that are very humid. Drainage around the building is poor. Polk Street drains directly toward the building, and if gutters are clogged, water builds up like a lake near the front stairs. The open veranda at the back of the building does not slope away from the lobby, requiring maintenance personnel to sweep rainwater from the porch as it collects. Further, visitors entering and exiting the building bring umbrellas and wet apparel into the space (in addition to saturated air outside), adding to the elevation of ambient humidity. In such circumstances, bubbles of detached canvas appear throughout the room. When dry conditions exist, the number of delaminations decreases, and can be found only by sounding the wall (tapping the surface and listening for the sound characteristic of a hollow space under the canvas.)

Conservation Treatment Report 2009-2010 6

•c --T - j Note bubbled separations between canvas and the wall

The walls have occasional settlement or drying cracks, which are mimicked on the surface of the mural in the form of cracks in the paint film. Losses in the wall structure of the south interior wall relate to holes, which were drilled to hang signs or devices such as the fire alarm. The north wall window bays have numerous small holes and plastic anchors from the old curtain hardware. Both east and west walls have small holes near the return air grids.

Holes

Plastic anchors

The most serious structural damage to the mural occurs at the top center of the east and the west walls. The damages are symmetrical, so may have a common cause. There are horizontal lines approximately I 0 feet long of crimped/lifted canvas with obvious bulges resulting from salt efflorescence, which appear as white powder along with white spots of paint loss (on the west wall). Both east and west canvases may have been compressed by changes in building statics, or (as in the west) may be due to water seepage as well, although engineers have not determined a cause. There is evidence of major water leakage in the ceiling from leaks above, but these areas are remote from the vertical walls. One observation from a journeyman plasterer, which seems plausible, is that the method of plastering the walls may have contributed to the distinct location (and symmetry) of the damage. Typically, the ceiling and a portion of the top of the wall are part of the same application of wet plaster. The walls are plastered afterward from the bottom to the top, and there may be weakness at the join for a variety of reasons. Water

Conservation Treatment Report 2009-2010 was surely present by virtue of mold and staining on the west wall, but the east is nearly devoid of water issues, despite bulging canvas, insecure plaster, and paint losses.

West Wall

Long cracks, buckled paint, and canvas

East Wall

Another area of large separation of canvas and apparent water leakage is found at the top of the northwest stairs on the north wall. This area is badly buckled in a giant amoeboid shape, and has palpable salts and debris behind the canvas. (See image at top pg. 7)

Priming:

The priming is an unknown white layer without a lead component. Seams at the joins of the canvas are very difficult to find, and when they are apparent, they appear to be mudded over, as at the south window bays. These areas are sometimes visible in specular or raking light.

Paint Film:

The paint film appears to be oil based; a technical analysis of paint samples of the background indicates the presence of copal resin in oil, however, the addition of wax was not confirmed. Application varies from a paste consistency to slightly thin, and there are occasional appearances of textured brush stroking. Although most of the design is well blended and without impasto, some low impasto is found on some very fine details of coral, rocks, and fish.

Most of the paint film, apart from the background, is in relatively good and stable condition in regard to attachment of paint to canvas, with lightly defined age/drying cracks. There are a few examples of traction cracking, mostly in fish painted over metal foils. The exceptions to stable conditions exist in the upper right and upper left of the north wall, around the blue octopus at northeast, and in parts of the top of the northwest and southwest wall, where actively flaking paint was found (possibly due to moisture).

There are numerous paint losses/abrasions, which derive from mechanical damages, less so from inherent structural instability.

Conservation Treatment Report 2009-2010

White paint losses due to mechanical damage

Losses of green paint around blue octopus due to moisture and poor adhesion to underlayer

The problematic attachment of the paint film is mostly confined to the various blue patterns of the background. Numerous changes by the artist were discovered throughout at the top scalloped design near the ceiling, especially on the south wall. There are several areas of pentimenti, where two different designs can be seen together, indicating a change of the artist's plan. Much of the wave-like scallops of different blue colors appear to have undergone revision, either in form or in color. Where two designs meet or overlap, there is telltale interlayer flaking paint, indicating poor bonding of the top paint to the surface below. There are several areas where the outlines of fish have changed (e.g. fish tail at extreme top right on south wall, fish near bubbles at top of stairwell panel of northeast wall). The paint film of the background, in general, is more given to flaking and insecurity than the design elements in multiple colors below.

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Conservation Treatment Report 2009-2010 The Aquatic Park Bathhouse Murals by Hilaire Hiler, 1939

The outline of a fish is badly flaking due to artist's change

Mechanical damages are most serious near the top of the wall where ladders were apparently used to change light bulbs. Not only were ladders placed directly against the walls, but they produced many scrapes down the walls, as they were dragged across the surface. The most obvious and most numerous damages are the result of building maintenance and occupant use, not as a result of visitor traffic as one might expect.

Graffiti is very limited, for example that found in pencil on the east stair wall, and on the east triangular wall.

Graffitti

Ladder scrapes

Fading has occurred in the window bays of the north wall, but not nearly to the extent of the south wall. Direct exposure to light has caused rapid ageing in the form of cracks, loss of color, and friability of the paint. Where shaded by the cross members of the windows, the colors and condition of the paint are preserved intact.

Fading and rapid ageing has taken place selectively where the mural is exposed to direct sunlight.

Darker, intact colors exist where shaded by former curtains (toward the center of the room) or by the metal crossmembers of the windows.

Conservation Treatment Report 2009-2010

IO

Overpaints:

There were several areas of overpainting, made obvious by virtue of mismatch of color;

they are darker and more opaque than the surrounding areas. This is a signature characteristic of retouchings in oil paint, which darkens with age. The most apparent overpaints were found in the horizontal green pillar of the northeast wall, the pink column on the east triangular wall, and in the window bay. number 12e just right of center on the north wall near the bottom edge. Alterations were also made to the leaves in a plant at bottom left of the east wall. While these paints drew the viewer's attention in a disturbing way, it was very difficult to remove them safely either mechanically or with solvents.

Surface coatings:

A varnish film is acknowledged in the historical notes, and has been said to contain stearates, which are flatting, extending and thickening agents used in old paints and varnishes. Stearates were typically added to shellac, to diminish surface reflections. A stubborn discolored film is noted on most of the mural surface however, analysis shows this film to contain oil and silica. The coating appears to have been applied haphazardly in some areas. and perhaps not at all in others. In spaces between the windows on the south wall, the coating is more visible where it may have been applied more thickly.

There are straight lines of the coating continuing straight up to the ceiling from the narrow sections between the window bays, and these are somewhat shiny in appearance relative to the surrounding adjacent surfaces. The oil component of the varnish is not common in an artist's varnish, but more similar to a spar varnish, or commercial coating.

It is unknown when or by whom the coating was applied.

Grime Layer

..._ ._ ~ .d - Varnish layer

Conservation Treatment Report 2009-2010 11

A very greasy layer of soot is found overall. Areas above the marble wainscot are rubbed, and considerable embedded hand soil is located in the lower part of the mural at the stairs. Huge halos of black soot reside above the heat registers on the south wall.

Localized staining and splatters of foreign debris occur throughout. The comers of the room and the surfaces above the cold air returns are literally fuzzy with airborne particulates. Near the ceiling, numerous black handprints attest to many changes of light bulbs by thoughtless workers. As expected, the accumulation of greasy airborne grime was greater near the ceiling, tapered off through the middle, and then became heavier again near the bottom edge.

Handprints at top of wall Surface ••fuzzy" with airborne debris

The east wall is unusually splattered with an unknown liquid which has etched into the paint film. Drips and splatter marks are found in many locations in the top third of the wall, and lower down in the silver fish at lower right. The nature of the spills is not known, but most have a terminus or precipitate that is white, and may have some relationship with repair of the plaster ceiling.

Conservation Treatment Report 2009-2010 The Aquatic Park Bathhouse Murals by Hilaire Hiler, 1939

Splatters of unknown material

TREATMENT

Cleaning:

The most complex and perplexing part of this work involved the cleaning of the mural, due to idiosyncratic responses of the paint film and old varnish coating to various cleaning agents, including both organic solvents and aqueous based solutions.

The conservators had experience with the window bay panels prior to starting the main lobby room. In the window bays, the haphazardly applied original varnish coating (containing oil and silicates) was greatly deteriorated, and had a tendency to blanch.

Cleaning of the mural could only be done with limited exposure to aqueous cleaning agents and organic solvents, even without attempting to remove the old discolored varnish. The varnish appeared to be intact in the main portion of the room, where exposure to light is far more limited. Regardless, the first tests with aqueous cleaners, ammoniated and aqueous solvents, in Panel 1 proved deleterious, due to blanching of a coating. A very slightly acidic solution was also tried, but it had a tendency to blanch, as well.

The work proceeded to include testing with a variety of naptha-based gel solvents. These produced much better results, especially in areas of deep color, where the coating did not blanch. Gel application was always fo]]owed by rinsing the surface with naptha. Despite the heartiness of the coating to this type of gel (containing naptha, carbopol, ethomeen and triethanolamine), the paint film itself was sensitive with repeated exposure; some colors were more soluble and sensitive than others. A pattern of predictable results was not discovered, and this left the conservators with the task of working together very quickly where possible to avoid lap lines, especially where the soot layer was very dense.

The cleaning method varied in both application and rinse methods, and was adjusted for each color area.

The blue areas at the top of the mural, which constitute a great percentage of the design, were particularly problematic. Numerous changes in design became apparent once the soot was removed. Buried beneath the grime are pentimenti and differing pattern of varnish application. Parts of the cleaning became spotty, due to these various changes in the artist's materials and working method, and in the ability of the conservators to predict these changes by modifying their own working methods and materials.

The paints are soluble beneath a strong coating of varnish, and the varnish is not a uniform layer. With every solvent system, there appears to be some risk; therefore, great care has to be taken when cleaning this mura1.

When faced with the very unsatisfactory action of the gel solvents over the main entry doors, the conservators tried again to clean with aqueous ammoniated (or slightly acidic) cleaners. Ammoniated water, pH 8, improved the working method unless/until the varnish film blanched. At this point, gel solvents were again employed, proceeding with extreme caution to avoid lap lines and bleeding of sensitive paint, especially in the blue background. Use of melamine foam micro-pore white sponges helped lift soluble debris

Conservation Treahnent Report 2009-2010 13 from the surface without much friction (which could be damaging), and helped control the amount of water used in the cleaning. Reduction of the amount of moisture was critical, since the conservators discovered that too much caused lifting of the unstable paint in the top section of the northwest part of the north wall (already friable).

Alternating cleaning methods resulted in a dramatic visual change that greatly improved the appearance of the mural. For example, the contrast increased and the intensity of the colors was revealed.

Signature found:

Cleaned sections

Not yet cleaned

Cleaned

Not yet cleaned

The side window bay panel designated N 12e, just to the right of the ranger's greeting desk, and almost center in the room, had a very soiled and bumpy surf ace. The bottom 18" was heavily painted and discolored by comparison to the areas above; the area was badly stained with water drips, and the sand design was slightly different from the south facing part of the wall to which it should have aligned. Test cleaning this area proved Conservation Treatment Report 2009-2010 14 that organic solvents, applied with friction, could remove the apparent overpaint, revealing a fairly intact original design below. The decision was made to clean the area down to original paint, as this might rectify parts of the design. After uncovering a black letter, further effort uncovered a great part of the artist's name, with a large repaired hole in the center, where original canvas and plaster was missing. This large gouge may have been made deliberately during the artist's walkout, but this is speculation.

Signature

Stabilization of flaking paint:

Areas of flaking paint were coated with Acryloid B72 (ethyl methacrylate/methyl acrylate, Rohm and Haas), under and around the flakes to the extent possible. After drying, these areas were returned to plane with a hot air tool and heat spatula, combined with hand pressure over silicone release Mylar. Pressure was maintained on the surface until cooled. Results were good, and light friction does not now disturb the paint. Since the paints had been lifted and cracked, even with flattening there is a textural change that can be noticed in specular light. This is not disfiguring in normal lighting and viewing.

The residual 872 was left in place to help fill the spaces around the paint and to provide a seal against moisture.

Varnishing:

Due to the continued use of the building, old heating system, increased public visitation, and possible need for future surface cleaning, a varnish is needed to protect the surf ace of the mural against airborne soil and human contact. Varnish not only helps protect the paint surface, it also serves to saturate color and to provide a separation between the original surface and the materials used by the conservator to make repairs. Varnish also helps blend the final appearance, so that areas of inpainting are not distracting in themselves. The old varnish was not sufficient or continuous enough to be a reliable protective coating.

The mixing of matting agents into the varnish helps reduce gloss to avoid undesirable reflections from the surface of the mural. It is the conservators' wishes to maintain the

Conservation Treatment Report 2009-2010 original appearance of the mural without alteration, if possible; this meant keeping the surface sheen as an "egg shell" surface, and to have the paint film not appear dry, yet no more glossy than before treatment. Reflections from the surface already existed, but an effort was made to work with the architecture, specifically the ambient lighting from the windows, to avoid unnecessary glare. There will always be some sheen as the viewer looks at the mural; this was true prior to treatment, and cannot be avoided entirely.

The varnish formula was altered in different locations of the room. Surfaces at the ends of the room, which are shaded from light of the windows, received varnish with slightly less matting agent than those areas toward the center, across from windows. The mineral spirit acrylic varnishes with ultraviolet light stabilizers (Golden MSA gloss and satin, in a proportion of 5:2, then l: I, and finally with a I 0% by volume of matte over the south doors) were applied by brush. The varnish was diluted with VM&P naptha. After inpainting, any matte areas of inpainting were further brush varnished locally to bring them into balance with the rest of the surface.

Reattaching Canvas:

Areas of separation between the canvas and the wall were located by sounding (tapping the surface) and by visual scrutiny under raking light. A solution of starch paste (Dynamite brand clear strippable heavy duty paste #785) was delivered below the canvas by hypodermic syringe, leaving an escape airway, and then was spread by rolling a brayer over protective tissue, until contact was confirmed. Residual paste was cleaned from the surface carefully; this was greatly aided by the varnish, which protected the mural surface.

The large separations above the stairs on the northwest section could not be set down without cleaning the old powdered adhesive and salts from beneath the canvas. To accomplish this, several large cuts were made into the mural, faithfully following edges of lines, contours in the design, so the repair could be facilitated and barely noticeable.

Debris was removed mechanically and with a vacuum cleaner with low suction. Paste was spread largely by a brush, and filled into small areas with hypodermic injection.

Injections in process

Conservation Treatment Report 2009-2010

Repair at center wall, East and West:

Damages along the horizontal cracks at the center of the walls were cleaned as possible prior to the start of the repair. Some of the paint was so extremely friable in this area that not all could be saved. Strategic cuts were made to the canvas following the design contours to open the area for repair.

In the case of the west wall, significant loose attachment of canvas existed above the crimped horizontal cracks, all the way to the ceiling, then continuing onto the ceiling itself. Repair of the ceiling would be contracted to painters later, but this area would come dangerously close to the finished mural. The conservators suggested they ameliorate any problems adjacent or tangential to the mural, and this was approved, so no future work would jeopardize the adhesion of the top edge of the mural.

Canvas on the ceiling was cut and draped down in an approximate 4' area for repair. The canvas was rolled onto a tube, and attached to the framing of the light fixtures. In this way the top of the mural and part of the ceiling would be opened at one time to allow for best alignment, and paste delivery. This would also give the plaster worker enough room to float out his patch materials. Tissue facings were added to the top edge of the remaining secure canvas, and these were lapped onto the wall, to create a dust barrier preventing debris from collecting behind the canvas. As the canvas was rolled back, right and left. brushes and a vacuum cleaner were used to catch debris. Scalpels were used to scrape away plaster and old adhesive clinging to the verso of the canvas.

Wood shelves were built to cantilever close to the mural, and were hung from the sturdy metal lighting fixture. These became platforms to receive the rolled canvases. The platforms hung close to the wall so tubes could sit vertically upon them, out of harm's way, while work proceeded on the wall itself. The wall plaster was tapped and gouged so that all loose plaster was removed from the area.

The damaged portion of the east wall was different in that no separations or plaster damage were noted at the top of the wall, only in the horizontally cracked and crimped line (approximately four feet down from the ceiling). In this instance, the canvas was cut in an arc, following the design contours, leaving the mural attached along the top edge.

This required rolling the mural upward onto a tube, and again attaching wood shelves to the light fixtures to hold the tube securely during the wall repair. As stated above, wall surfaces were cleaned of loose plaster and debris, and the edges of the remaining attached canvas below were shielded with tissue facings.

To prevent puff-back of plaster dust, all areas of the mural were surrounded with a thin tent of drop cloth plastic. Greg Conway, the journeyman plasterer who repaired the wall (from Ruane Company. South San Francisco), cleaned the exposed wall surface. He then used a product called Weld-crete, a bonding agent over the broken joint in the plaster.

This was followed by a scratch coat, and then a brown coat, made with Structo-lite, using perlite as the aggregate. The finish coat containing gypsum is a "hot" 20 minute smooth set taping mud, which was sanded smooth when dry and sprayed with Zinzer shellac based BIN primer and stain killer.

Conservation Treatment Report 2009-2010 17

After drying three days, the canvases were mounted back to the walls, using the same paste adhesive mentioned above. The walls received a brush coating of l: I paste/water for slip and improved tack. This was let dry for about one hour. A second coating of heavy paste diluted in water less than I pint per gallon as per product instructions was applied by roller and brush. The canvas was unrolled from the tube, and the crimped/creased areas of the verso were wet lightly with a sponge. Pressing to the wall was done with brushes and brayers over waxed paper, smoothing and removing trapped air bubbles. The canvas relaxed in about one half hour and was rolled again. Creases remained, and the final effort to flatten and secure the canvas was done with tacking irons above silicone release paper. This final step and the drying process itself, pulled most distortions out of the canvas. Results were excellent considering the great amount of distortion in the canvas and paint prior to treatment. The conservators worked for several more days refining the attachment with syringe injections in any remaining voids.

Rolling back canvas after cutting On West Wall

Canvas rolled onto tube, stands on wood shelf

Canvas on East Wall is cut and rolled upward

Conservation Treatment Report 2009-2010

Compensation of losses:

Holes in the plaster were filled with spackling paste (Dap vinyl spackle) until nearly level, then finished with microcrystalline wax (Bareco Victory white, mpl 75F) which could be easily sculpted to resemble the surrounding spaces. Some few holes, and the signature area, were fitted with patches of canvas prior to the application of wax. Most areas near the ceiling were filled with spackle only, or, in the case of the repair of cuts to the canvas, wax was the most easily workable, and adds some protection against the response of the paste adhesive to the atmosphere.

Not all losses were filled. Shallow areas of minute flaking paint or interlayer cleavage were usually not noticeable, and these were inpainted only.

Losses were filled with white spackle and/or microcrystalline wax

In painting:

Inpainting was made difficult by the shifting slight sources within the building, which were a combination of incandescent and natural light, through the many windows and doors. A shift of color temperature occurs from top to bottom, from warm to cool.

Defining the optimum color match was somewhat arbitrary, and a great deal of effort was made to match colors in a manner that produced the best match under most times of the day, and in ambient conditions. Artificial lights of one color temperature are not satisfactory, as they do not accommodate the natural mix of light during most viewing times.

Some dull areas in the mural are the result of light reflection off bumpy areas of surface, caused by debris under the canvas, or by canvas threads, or by damages to the paint film during execution of the piece. Light reflections will sometimes appear to be light spots, or appear dark due to textural shadows.

Conservation Treatment Report 2009-2010 19 The Aquatic Park Bathhouse Murals by Hilaire Hiler. 1939

As previously stated, the greatest difficulty was presented by the change of light, color temperature, throughout the day. By and large, areas up high were inpainted under house lights, and down below daylight fluorescent lights or actual daylight. Most of the inpainting was done with LeFranc and Bourgeois acrylic resin restoration tube colors, soluble in naptha, xylene, or acetone/naptha. Since LeFranc monastral/thalo blue was unavailable, the addition of thalo blue and thalo green conservation colors based on aldehyde resin from Gamblin were added where needed.

Varnish was added to some of the inpainting tube paints, and this helped secure areas of flaking and interlayer cleavage.

In the final scrutiny of the work, certain areas were altered by using Prismacolor colored pencils. This was very effective in making slight alterations, especially when lightening a dark color, and were especially useful in the inpainting of the sand near the entry doors.

Numerous small stains could be altered in a more timely way using the pencils rather than inpainting with solvents and then varnishing. Sprays of satin MSA Golden varnish were used to matte the surface in areas of large losses with obvious textural abnormalities.

Signature area after inpainting

Details from page 9, after treatment

Conservation Treatmeltt Report 2009-2010 20

Ceilings of Window Bays on South Wall:

Part of the contract with the National Park Service required repainting the ceilings in the south wall window bays. The conservators decided to retain and repair the ceiling in the first southeast bay, so this can remain a distinctly original paint scheme. The five others were in various states of repair, with patches made by ARG's plasterer.

The five ceilings were coated with Acryloid B72 resin to retain their existing condition under a barrier film. They were then primed with a latex primer from Kelly Moore (Glidden Gripper Interior/Exterior Aquacrylic Primer Sealer, MFG Model #GL32I0- 1200-0l).

A color match was made using an ICI paint fan (which was also used by ARG for their color study of the ceiling), to maintain consistency. The closest match, which was painted in semi-gloss was from the fan called Master Palette, and had the name "Seven Lakes" ICI (Fuller), #1244, 90GG 30/195. The next darkest color on the chart was painted on the narrow wall surfaces at the top of the stairs, as a better transition from the mural to the stairways. The stairwells themselves may be painted this darker color at a later time, according to the Park Superintendant.

The ceiling color was deliberately painted in a thin sketchy manner by brush, trying to duplicate the original appearance. Further, the conservators made a colored glaze of translucent pigments in Golden MSA varnish to create some depth to the color; they applied this glaze themselves to mellow the otherwise fresh appearance of new paint.

The five repainted ceilings have a very close resemblance to the original now.

Co11servatio11 Treatment Report 2009-2010

0 rio n ANALYTICAL. LLC A Materials Analysis and Consulting Firm Po$t Ollitt! flo• 550, W11Ji<11m1own. MA 011.1>7 USA 1413)456·0233 fa. f4 I 3J45fl.0134 inloG"otlon.m.1lyllrnl.crnn wv1tw <>rionan.1ly11•,il.com

March 2, 2010

Thank you for asking Orion to assist your study of an intractable coating on the surface of a mural on the south wall of the Bathhouse, main floor at the San Francisco Maritime Museum.

Orlon analyzed the coating sample using Fourier transform infrared microspectroscopy (FTIR), a method commonly used In museum, forensic, and Industrial laboratorles to study paints and other coatings. The resulting mR spectrum of the coating sample showed features consistent wlth alkyd resin and what may be sillca (perhaps added as a flatting agent).

It has been a pleasure to asslst you. Please do not hesitate to contact Orion if you have questions about this report or would like further analyses of the sample.

Very truly yours r·£VtM~ Orlon Analytical, LLC

By James Martin, Principal

Sample No: Maritime Museum/Entrance Hall Blue Paint

Equipment: Thermo Nicolet /RJOO FTIR, Thunderdome ATR Cell Spectrum No: Purple Trace, Sample Spectrum; Green Trace, /RUG Standard Copa/ Resin Standard, Red Trace, IR UG Standard Na Silicate Run Conditions: Resolution 4 cm-I; Transmission Mode; Gain 4; No of Scans = 32 Software: EZ OMNIC, proprietary Thermo-Nicolet software used for conversion to absorbance mode; baseline smoothing and corrections; peak assignments; library searches, spectral subtraction, and interpretation Libraries: Hummel Polymer Library; /RUG Standard Library 2001 File Type: TIFF

Estimate: Cooal Resin; Silicate; Possibly Wax, Oil +Additional Materials D.9:

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Note the spectrum of the paint is obvious complicated because ii contains so many different materials that are overlaid one over another. The best general match is to a fossil resin like copa/, but this belies the fact that there can still be minor wax and oil components that obscured by the predominant IR absorption bands for the fossil resin.

One salient note is that the paint spectrum contains a very broad band at 1090 cm-1, which usually corresponds to a silicate (the standard is included here in red). This may ,. .

be one of the ways in which Hiler 'modified' his paints to be more matte and 'fresco-like' in appearance, by including a substantial amount of some kind of silicate in bulk to the paint to help scatter light. I haven 't include here the spectrum for Monastral Blue (Phthalocyanine Blue), but it can easily fit with the absorption bands present ... especially those below 800cm-J, it was just too crowded in the image with everything super-imposed. For comparison 's sake I've also included the second FTIR Spectrum below, which was taken with the ATR eel/from the underside of your sample, in the white priming or prep layer (non-colored, non-blue).

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Here again, the sample is in green; the Copa/ spectrum is purple; and the red is the silicate standard Conspicuously absent are the absorption bands below 800 cm-1. By the way, the paint in the main level entrance hall looks decidedly different.from the Primatarium paints, which are essentially oil bound (poorly bound ... but none the less oil containing).

-RCW 10113110-