20 May 2019

Digital manipulation as a teaching aid

Posted by Callan Bentley

I have a question for you. It’s about teaching geology.

Consider this photograph, by Tim Johnson, of an outcrop in the Buchan block of Scotland, near MacDuff:

Tim took the photo because he was impressed by the graded bedding and the “baby load casts.” And rightly so!

But there’s much more in that photo than just those features. It also shows percussion marks, and veins and joints (fractures), and it’s got a bit of colorful lichen on it too. And in addition to the coin (for scale), there’s modern sand in the lower right.

In short, there’s a lot to look at.

If a teacher were to be focused on teaching primary sedimentary structures such as graded bedding, and they wanted their students to see the “graded bedding” part of this image without risking getting distracted by the other details, would it be ethical to remove some of those other details using digital manipulation of the photo? (i.e., specifically by using Photoshop’s “cloning” tool)

Tim’s outcrop inspired me to try!

…For instance, what if we took away the percussion marks?

…What if we got rid of the veins?

…What if we got rid of the fractures?

…What if we did a “virtual pressure washing” and stripped away the lichens?

So the final result would be rather significantly less “real” than the original, but it may be more useful for teaching purposes, allowing students to focus on the graded bedding, and not be distracted by the other types of information/data/noise in the actual outcrop. Images modified in this way are not truly authentic, but they may make for easier learning, especially among novices who don’t know what to focus on. (I’m reminded of Werner Herzog’s “ecstatic truth…)

Is it ethical to modify images in this way? In textbooks? In classes? (…on blog posts?)

In summary:

I’d be curious to hear your thoughts about where the limits of this sort of digital manipulation lie.

Here are a few more examples I worked up, with the goal of stimulating discussion:

Relict cross-bedding in Weverton Formation quartzite, Thoroughfare Gap, Virginia:

Layered gabbro in the Stillwater Complex, Montana:

Fold in metagraywacke, Billy Goat Trail, Maryland:

Okay – let’s hear it: How do we most ethically utilize this powerful technique?