Generally speaking, when you hear of heritage visualisation, you’re first reaction may be something along the lines of, ‘What’s that?’ A perfectly valid reaction, since we tend to talk about visualisation in terms of specific techniques (e.g. photography, 3D modelling, etc.) rather than as the more general term. Heritage visualisation is simply representing heritage materials (e.g. objects, sites, monuments, texts, etc.) in a visual way. Drawings, photographs, and 3D models all fall under this larger term, as well as any other way of visually representing these materials.
So now that we’ve established what heritage visualisation is (at least on a very general level), what’s the purpose of it?
I feel there are two main points here. The first is to convey visual information from one person to another. Usually, the person creating the visualisation is someone who can physically access the object in question, and they are trying to convey that information to someone who cannot. These issues of accessing material often have to do with physical distance – the object is in the US, but I am in Scotland and cannot physically get to the US at the moment.
But we can also be separated by time. A perfect example, however sad, is the recent destruction and recovery of Palmyra. Due to the destruction, photographs, site plans, and other visualisation are the only way we can see the Temple of Bel as it was before the destruction. These representations will also aid in the reconstruction of the site, and once that occurs, the images of the destruction that have been circling recently will be one of the only representation of the extent of destruction itself (which most will argue is equally important in the life cycle of the site). All of this is important in terms of archival and preservation work.
The second main point of heritage visualisation is to discover new information that we might not otherwise see. I study beads, which should be pretty evident from this blog. The majority of beads in archaeology is less than 10mm (0.4 in) in diameter, and the most beads found are less than 6mm in diameter (0.25 in). Sometimes we have trouble just seeing the bead, let alone things like wear patterns or bubbles. But we can through visualisation – macro photography is a wonderful thing.
And it’s not just general photography. I can use certain filters to emphasise different characteristics, to ‘opacify’ the bead in order to see outside wear patterns or to see through the bead to get at bubbles or the perforation itself. I can take a series of images with different lighting to see how that affects the object, and I can capture images using non-visible spectra to get at non-visible (or barely visible) characteristics. And I haven’t even started talking about 3D representations yet.
Now that we’ve established the general purpose of visualisation (at least as I see it), there is one feature of visualisation which I see as a major asset, though others might disagree: Heritage visualisation is not about representing an object 100% accurately.
Now, before you scoff and close the window, hear me out. It isn’t possible to create a visual representation of an object that conveys all of the information you would receive if you were sitting there holding the object in your hand. We would love to be able to do that, but we can’t really do that at the moment.
This is in part because the technologies we have are really good at some things and not good at others. Photography is generally fantastic for capturing colour details, but really bad at capturing 3-dimensional characteristics. Depending on the object, photography may have a lot of difficulty even keeping the object entirely in focus, and conventional photography can’t generally get at sub-surface characteristics or things that aren’t visible to the naked eye. Reflectance Transformation Imaging (RTI) is really good at visualising the effects of different lighting and lighting angles on an object, but isn’t good for representing that object in 3-dimensional space.
This isn’t surprising when you think of visualisation techniques as being similar to our eyes. After all, they’re trying to replicate (or enhance) what our eyes do naturally. But when you look at an object, your eye is not simultaneously focusing on 100% of the visual information all at once. Instead, you focus first on colour, maybe, and then on surface features, then on sub-surface features, and so on. Current technologies are like our eyes focusing on one characteristic at a time. Each one can represent certain elements really well, but as a result, aren’t so great at others. As a result, they can’t create a 100% accurate visualisation of every characteristic of an object.
But in many ways, that’s not really our goal. Our goals are to convey information to other people and to discover information that may not be visible (or noticeable) naturally. We don’t need a 100% accurate visualisation to do either of those things, we just need them to be really good at what we’re using them to convey or investigate. We can then combine different visualisations to achieve an accurate (and often enhanced) understanding of these objects. So long as the information is conveyed or discovered (as per our goals), it doesn’t really matter that we need more than one visualisation to do that (though some require heftier budgets than others, which is a whole other can of worms that I can’t get into in this post, but which I certainly recognise is a factor here).
So long as we know the strengths and weaknesses of each technique and we know what we’re trying to get at, we don’t need to create a 100% accurate model. Issues arise, however, when we expect a technique to be accurate in ways it absolutely isn’t (or can’t be), when there is a discrepancy between our expectations of a visualisation and what that visualisation can actually do.
Which leads us back to the question, ‘What is the purpose of heritage visualisation?’ It’s a question about the general applications and goals of the field, and also a question about a specific instance of visualisation. We have already discussed the general goals of conveying information to others and discovering new information we might not otherwise see. But this question is as much about determining the purpose of an individual visualisation attempt as it is heritage visualisation in general.
A lot of people want to make 3D models of lots of things. It’s a great technology, and people are jumping on it left, right, and centre. It’s amazing. But one question that often comes up in the process is why. Why should we create a 3D model of this object?
What we generally mean by that isn’t ‘Why bother?’, it’s more along the lines of ‘Why is a 3D model the best way to visualise this object?’ ‘What do we want this model to do, and why is a model the best way to do it?’ We all agree that 3D models are great, but it may not be the best technique for what we want to convey or discover. RTI might work better, or infrared photography, or some form of line drawing.
The specific purposes of each visualisation will differ – one will want to emphasise subsurface characteristics while another wants to create accurate surfaces for measurement purposes. Another may want to examine inclusions in the material while another wants to see if the shadow an object casts (particularly translucent ones) can show us any new information.
In the end, then, the purpose of heritage visualisation is to convey and discover information, while the purpose of specific techniques or a specific occurrence of heritage visualisation is directly related to the information the creator wants to convey or discover. It’s not about 100% accuracy across all characteristics in a single visualisation, it’s about understanding which techniques work best for which purposes and how we can combine those to convey or discover the information we want.