March 25, 2013 to December 28, 2013


Scattered areas of weak paint were individually stabilized using a 1:10 gelatin adhesive. The liquid adhesive was applied warm using a small sable brush. This initial step allowed treatment work to continue without risk of further loss.

Katharina von Bora

The cleaning of an oil painting involves the removal of discolored surface films and all areas of non-original paint. An understanding of paint chemistry is required to remove these films without injury to the surface. This work is carried out under binocular magnification using cotton swabs and appropriate solvents. The upper dirt film was removed using a mild pH-neutral detergent while the varnish layers were removed using organic solvents. (9)

Varnish removal began along the right side of the painting. Oil paint becomes milky as it ages. As a result, darker tones will appear blanched or bloomed after cleaning. Later revarnishing reinstates a color's original richness. The below left image documents the color change that resulted from removing the overlaying films. The right image offers a corresponding detail.

Full View During Cleaning

Detail During Cleaning

The removal of earlier restoration work revealed former losses and heightened the upper-right corner’s visual inconsistencies.

Full View After Cleaning

Upper-Right Corner After Cleaning

Martin Luther

The cleaning materials for the Luther panel were identical to those used for Katharina’s. The dirt film was removed using a pH-neutral detergent and the varnish layers were soluble in organic solvents. Washes of overpaint were encountered throughout the dark tones to mute small abrasions along the wood grain. During cleaning, an area of hardened white overpaint was revealed in the upper-right quadrant. This area required scalpel assistance for removal.

Full View During Cleaning

Detail During Cleaning

White Overpaint


As stated in the introduction, “whole sections of paintings may be overpainted, hiding long-forgotten original intent. Only bits and pieces of information may remain after centuries of former restoration work and damage.” This occurred during the removal of the Luther portrait’s varnish and restoration work. The silhouette of a scraped-out coat of arms or seal, and two lines of a missing inscription were discovered in the lower areas.

Full View After Cleaning

Coat of Arms After Cleaning

Lower Inscription After Cleaning

Fully cleaning the upper sections of both paintings brought out an additional discovery of faint lettering. Only a few letters on the first line of a possible five- or six-line inscription on the Luther portrait were legible–the letters D O C T O R   A R T   V S  L V–but all of remaining letters, and all of the letters on Katharina’s portrait, were illegible. One could reasonably infer that the Latin text on the Luther panel originally read DOCTOR MARTINVS LVTHER.

Detail Luther Upper Inscription After Cleaning

Detail Luther Upper Inscription With Known Letters Above Readable Letters

Detail Katharina Upper Inscription After Cleaning

X-Rays/Infrared Photography

In order to determine a possible solution to the missing inscriptions, two further investigative procedures were undertaken: X-rays and infrared photography. X-rays allow conservators to understand certain aspects of a painting's condition history. They can detect holes, tears, under-drawings, and areas of former restoration work.

X-rays will pass through most objects but are blocked by pigments that contain heavy metals such as lead white; these areas appear white on x-ray film. Unfortunately, the X-rays produced no clarifying information relative to the former inscriptions and only the Katharina panel presented a reasonable image, although the backing cradle severely compromised its resolution. (10)

Detail Katharina X-ray

Infrared photography can be used to see into the layers of a painting providing information that is not visible to the human eye such as under-drawings, variations in composition, and hard-to-read inscriptions. The technique can detect carbon-based materials such as graphite and certain black pigments.

The infrared images sharpened the known letters on the first line of the Luther inscription and revealed additional information on the second line. It was now possible to read the letters P R O P H E T–probably PROPHETA originally, the Latin word for prophet, and an additional S. The infrared examination of the scraped-out seal, the scraped-out lower two lines, and Katharina’s upper inscription offered no clarifying information. (11)

Detail Luther Infrared Upper Inscription With Known Letters


Filling has two purposes. It prevents further damage by sealing the edges of holes, tears, and cracks. It is also used to reproduce a sympathetic surface with respect to plane and texture. Minor areas of loss on both panels were filled with gesso, a mixture of marble dust and a 1:7 gelatin adhesive.


A brush coat of Winsor & Newton non-yellowing varnish was applied to the paint surfaces. Varnish is applied for several reasons. First, it reinstates the richness of the paint by allowing the darks to have their proper tone. Second, it keeps dirt and air pollution off the picture surface. Third, the surface coating protects the paint layer from damage caused by abrasion, moisture, and accidental accretions. The varnish also creates an ethical buffer between the original paint layer and the retouching or inpainting. Conservators do not paint directly on the original paint surface. The work is done on top of an isolating varnish and can be removed by simply removing the underlying varnish.


Retouching is carried out to correct visual inconsistencies caused by inherent structural problems or surface damage. Its purpose is to reduce or eliminate these inconsistencies. It is applied only to areas of loss and should never extend over the original paint. The retouching was completed using Maimeri conservation pigments. These pigments are both color- and light-fast offering confidence that the restoration areas will remain consistent over time. Also, the pigments are soluble in mineral spirits. This relatively weak solvent permits safe and easy removal without risk of injury to the paint surface. (12)


Ms. Jane Connell, director of collections and exhibitions, and senior curator, for the Muskegon Museum of Art, guided the retouching to include: leaving the abraded upper inscriptions in place for they did not detract from the paintings’ overall aesthetic balance; softening the visual inconsistencies in the upper-right corner of the female portrait; and fully retouching the lower scraped-out losses on the Luther portrait for these areas were visually dominant and visually disruptive. (13)

December 28, 2013

After retouching, the application of a final, non-yellowing spray varnish completed the nine-month treatment.

Before Treatment

After Treatment

Before Treatment

After Treatment

While the conservation work on the paintings was at an end, the hunt for the lost inscriptions and unidentified seal was just beginning. Would it be possible to determine the original Latin text? Whose coat of arms was in the lower corner? The following pages record the chronological efforts and strategies used to pursue the unknown information.

Page 5--The Hunt

Index Page,   Page 1--Introduction,   Page 2--Short Biographies,   Page 3--Examination,   Page 4--Treatment,
Page 5--The Hunt,   Page 6--The Inscriptions,   Page 7--The Rose,   Page 8--Final Thoughts,
Page 9--Endnotes


9. References for consolidation, cleaning, varnishing, and retouching from the author's 2005 Case Study, “A 1938 Portrait of Adolf Hitler.”

10. The portraits were x-rayed at 56 kilovolts and 3.3 milliamps for 6 milliseconds on August 18, 2013, by Ms. Tracy O’Brien and Mr. Thomas Daus from the Radiology Department at Shriners Hospital for Children in Chicago, Illinois.

11. Infra-red examination carried out with the assistance of Mr. Joe Barabe on March 29, 2013.
12. Filling, varnishing, and retouching purposes from Bradley, Morton C. The Treatment of Pictures. Cosmos Press, Cambridge, Massachusetts. 1950.
13. E-mail instructions dated November 20, 2013.



Barry Bauman Conservation
Contact: Mr. Barry Bauman
1122 N. Jackson Ave., River Forest, IL. 60305
Ph.(708)771-0382  Fax.(708)771-1532