ORP: Cruciform Brooch

THE OBJECT

The cruciform brooch I chose for my modeling and research paper was found in a cemetery at the West Stow site. Since brooches of a similar cruciform style were found in the same cemetery at West Stow and in other locations. Considering what has been discovered of other Anglo-Saxon grave goods, it is reasonable to assume this brooch accompanied a late Anglo-Saxon into the afterlife. Twelve brooches of the cruciform style were found in the cemetery, all made of a bronze alloy.[1] According to Stanley West, the brooch is typical of the Leeds Type V.f. and is a “remarkably successful, decorative piece, with a flowing, rounding design of masks and bird heads.”[2]

Brooches of this style were unique, one of a kind pieces due to their creation process. Although there had been some suggestion of lead molds used for cruciform brooches, the slight differences found between two “matching” cruciform brooches suggest that the lost wax modeling process was much more common. Since the mould was destroyed in removing the brooch, each piece would be hand designed. Because of this individuality, the time and resources needed to make each brooch would have kept them as a luxury item, not a more-mass produced form of jewelry. This individuality also makes it slightly more difficult to track the makers and styles of these brooches.

The complex ornamentation and decorations on the face of this brooch are possible because of the wax molding technique employed. Wax is a very easy material to work and requires less preparation than clay. Carving shapes, symbols, trick figures, and other designs into wax was much easier than trying to do a similar process in clay or lead. The softness of the wax meant that even the shallowest of details could possibly be molded – in this case, the triangle stamps stand out as a small but important detail. After the two-part mold was created, a superheated copper alloy could be poured into the mold, where it would harden. The wax would then be peeled away, destroying the mold, and the finished brooch would be revealed. [3]

The appearance of this object within a cemetery tells us much about Anglo-Saxon culture in terms of materiality and funerary practices. It is very conspicuously a higher status item and it was buried in the ground. Perhaps these are obvious facts, but their physical reality revealed a much more detailed picture. From this internment, we can surmise that it was important for religious or social reasons (or both!) for the deceased’s family to ensure they were buried with this brooch. Instead of passing it along as an heirloom and keeping their wealth on hand where it could have a continued use and serve as possibly liquidated wealth, it was buried in the ground, in a place where custom would have prevented its removal. Within a generation, family members would likely not have even had memory of its existence. The final importance of this brooch was to “die” alongside its owner and move into the next life.

Considered a “late” Anglo-Saxon brooch due to its complexity and craftsmanship, another key feature of this brooch is the hidden figures and faces in the design. As mentioned preciously, the brooch contains numerous birds and human masks. I have marked human masks in green, assumed bird faces in orange, and possible horses or birds in blue. These figures make up almost the entire outer edge of the brooch. They also face outwards at all directions, implying the brooch was something to be handled and studied from multiple angles in its life as functional jewelry.

 

THE MODEL

Allow me to begin by explaining the process I followed to achieve two workable models of the cruciform brooch. I knew from examining the photos that the cruciform brooch would not be a standard photogrammetry process. Some of the photos were blurred and the brooch itself was a reflective, metallic object that changed hue and tone as it was rotated. Even still, I attempted to generate an initial model based on unmasked, unedited photos, and was not successful. The variation in hue was too much for PhotoScan to place enough tie points and there was not enough contrast for distinguished features to be readily modelled.

I made the early decision to remove the background entirely from each photo (as well as the iPhone that appeared to act as a balance for the cruciform in some shots) and replace it with white pixels using Photoshop. I chose to edit the background this way instead of using PhotoScan’s built in mask feature for two main reasons, even though it meant a slightly longer process.

First, there is currently an ongoing Nvidia driver issue that shut downs the photo editing toolbar and makes photo tabs unresponsive. The workaround for this issue is to switch to the on-board basic Intel integrated graphics for any in-program photo editing, but I did not appreciate the lag that this fix caused when trying to rapidly and accurately trace the mask. Updating/rolling back drivers was also not enough to solve the issue.

Second, because of the object’s metallic nature and the use of a black background, many of the curves and contours near the edges were reflecting dark or black colors themselves, especially along receding edges. I had noticed earlier during my first test run that the program was having a difficult time distinguishing what was background and what was dark-colored curves on the side of the brooch. I wanted a white background because I knew it would force the program to view these dark areas as part of the object and not a background, and white was the highest contrast available. I know from experience that programs generally read white as data-less, while black and near-black pixels can usually have further definition coaxed out of them through careful editing.

Fixing the background by making it white did not fix the issue of hue changing with rotation. This was a much simpler fix in Lightroom. I used the built in black and white preset filtered for red and high contrast. With the color of the gold, filtering for reds offered the greatest consistency and clarity in object color.

With this step complete, I had removed the biggest complications of the images. I no longer had a dark background to consume and confuse the dark edges of the brooch, and without the hue complications PhotoScan was forced to pick out its tie points by examining the patterns it found in greyscale pixels.

Even with all this prep work up front, there were pieces of the model I could not generate from the images. While I consider the flat faces of the brooch to be overall successes considering the difficulties in preparing the images in a way that allowed me to achieve a model, I recognize that the tips are very messy in terms of data and filled with mountains and valleys caused by uncertainties and errors in projection, although all workflow stages were always run at the highest settings possible.

The thin side edges were a complete loss, but unsurprisingly so. Their thinness made it difficult for them to be captured in more than one or two photos at the angle intervals the photos were taken at, to photograph them in more detail would have been incredibly painstaking and time consuming for only a chance at a better final product. Their edge position also made them quite dark, and being thin edges meant they were relatively featureless and PhotoScan did not have much in the way of distinguishing features or patterns to generate tie points.

Modelling this object digitally required a certain level of spatial reasoning and abstract awareness that I assume the original maker would have had as well as they carved a relief or negative version of what the final brooch would become, especially over the complicated intertwining figures. The moments where I waited for a part of the workflow to finish processing before I dove in to manually clean up pixels may have some analogous emotions or processes. I believe the comparisons made from comparing this form of modeling to the original form of modeling would mostly be forms of inductive authenticity. My clicking and editing of photos has little in common with the process of carving and shaping wax, even I shared the abstract, mental, or emotional parts of making with the original creator.

My appreciation and puzzling over the object in 3D is much more realistic than studying the object through photos. Having a detailed model of the faces allowed me to zoom in and manipulate the object in space in a way that would only otherwise be possible with the object itself. This handling process was important to my decoding of the shapes and figures present and allowed me to have a better view and understanding of the triangle imprints left on the front of the brooch.

I mention the triangle stamp specifically because it was a detail I had not paid much attention to until I could see the shallow nodes it left on the model. After bringing it to my attention with digital manipulation of the cruciform brooch, I realized the process of stamping the brooch with geometric designs likely had a lot in common with the process of stamping urns with geometric designs. Both appear in funerary contexts, both involve regular geometric stamping, and both make much more sense in the physical context of their self and environment.

 

The results of my modeling were not watertight or perfect, but in my opinion, the missing segments are no worse than missing shards of pottery that were replaced with plaster. The sum of what was accomplished is greater than the void of what’s currently missing. I fully acknowledge that modelling is not a perfect process and despite our algorithms and machine learning, even the best-looking results may not match their object of origin 100%. However, 3D modelling is still worth exploring, as “digital handling” still has the potential to reveal properties or aspects of an object that are otherwise understated or unseen in photographs alone. I believe 3D modelling will also play an important role in preservation, especially for structures and objects that are rapidly deteriorating or may face environmental threats.

 

[1] Stanley West, West Stow, Suffolk: The Anglo-Saxon Village, East Anglian Archaeology Report 24, vol. 1, 2 vols. (Ipswich, Suffolk: Suffolk County Planning Dept, 1985). 142.

[2] West. 142.

[3] Kevin Leahy, Anglo-Saxon Crafts (Stroud, Gloucestershire: Tempus, 2003), 143.