The Treatment of Dog Jack from the collection of The Soldiers and Sailors Memorial Hall and Museum

I have had the great honor to work on several paintings for Soldiers and Sailors over the past couple of years.  All of them have provided unique conservation challenges due to previous interventions and general history.  Dog Jack proved to be no different and definitely no less rewarding.

Dog Jack is a beloved painting for the collection and a popular stop for youth and adult tours alike.  Jack, originally a stray bull terrier, was the mascot for the Niagara Vol. Fire Company on Penn Avenue and was enlisted in the 102nd Pa. Vol. Regiment during the Civil War. Jack fought alongside soldiers.  It is said that he was able to follow bugle calls of his unit. A valiant soldier, he was was wounded three times and captured twice, once later exchanged for a Confederate soldier at Belle Isle, Virginia. On December 23, 1864, Jack disappeared in Frederick, Maryland. (Information on his background was collected from the Soldiers and Sailors Memorial Hall and Museum and this Pittsburgh Post-Gazette article:

His story has inspired artwork, a book and movie.  A brief video on Dog Jack was produced by the Heinz History Center and can be viewed here:


The portrait is signed G. Prenter, 1899, and depicts Jack lying on his side, wearing a collar with a lock, in full eye contact with the viewer.  Numerous copies are known to exist, suggesting the artist painted from a photograph.

Portrait of Dog Jack, Before Conservation Treatment

Portrait of Dog Jack, Before Conservation Treatment

The painting was in relatively good condition, though exhibited a very thick and discolored varnish layer. The varnish appears to have been applied while the painting was framed, as there is about a half-inch of un-varnished surface around the perimeter where the painting was protected by the frame rabbet. This treatment is commonly seen, as applying fresh varnish can often "refresh" a surface and re-saturate the colors without fully cleaning the surface beforehand. This can lead to complicated future varnish removals, as layers are "packed" onto one another.

As was the case with Jack, the varnish was very thick and nearly impossible to remove using solvent solutions alone. After numerous tests it was determined that the varnish required swelling with a gelled solvent solution before it was able to be removed. The removal process proved to be quite tedious, as the swollen varnish often required mechanical removal/reduction with a fine scalpel. Solvent gels allow solvents to remain in contact with the surface for a longer period of time. 

The time lapse progression below shows the careful application of gel, the swelling of the varnish, the mechanical removal of the thick coating using a micro-scalpel and, finally, rinsing with a solvent solution to remove residues.

*Using solvent gels requires conservation training and knowledge of the materials involved and their solubility.  Misuse of solvent systems and gels can potentially damage artwork without the proper handling and knowledge. 


Many thanks to Soldiers and Sailors Memorial Hall and to curator Michael Kraus for the opportunity to work on this part of history.  The entire project was generously funded by Hillman Family Foundations.  Thank you!