In a shared folder for Gettysburg: The Tide Turns on our company network a few weeks ago, I saw a bunch of copies of photos of my face suddenly appear. They were added by Art Director Pat Ward, so I reached out to him to see what was up.

It turns out our art department has been hard at work creating filters to make regular photographs appear as etchings. This process will allow us to use a wider range of images and, yet, ensure that they all maintain a cohesive look and feel. – Brad Cummings

Here’s Pat Ward with an explanation of his process:

The historical sections of our Crisis in Command games have always been important to us so naturally we have every intention of including the same level of background information and visual detail in Gettysburg. I wanted to be able to use a lot of period images and mix and match them with our own and stock sources so we have the maximum amount of control. The vast majority of usable period illustrations come to us as etchings which, while they look fantastic, often don’t hold up practically to the level of scaling we need – reducing down loses the detail and scaling images to varying degrees results in an inconsistent look. Not what I want.

So I knew early on that the ideal situation would be to work from photographs. That way, whether the source was modern or period, I could maintain a consistent look and ensure the scale of the etching detail was consistent throughout.

I looked for commercial tools and bought two good ones for Photoshop, thinking there was little point in reinventing the wheel. The first gave excellent results but looked too mechanical and perfect and simply want versatile enough. Not the scratch-board look I had in mind as you can see below.

On the left is the style I was edging toward and on the right is the result of the commercial filter.

The second product offered more options but was unpredictable, seemed to work with only a small subset of images and the quality of the patterns provided left a lot to be desired. I decided to bite the bullet and create my own process so I could have the control and, hopefully, the results I want.

I could think of two ways to do it. The simpler is to use one texture with a pattern consisting of different levels of grey that could simply be clipped out based on the tones of the original image. The brighter the image, the more of the pattern is revealed; the darker it is, the more grey is clipped to black. A simple technique but the result would be very much the same as the commercial ones with nice subtle variation in tone but just the one pattern.

The second way is to try to mimic the approach of using cross hatching and changes of line density and thickness to create tone, much like the original technique. Naturally I chose this harder route!

I’d never created such a long Action before and Photoshops tools don’t make editing and refining particularly easy. This is a screen grab from when I was about 3/4 of the way through. Each line is one or multiple Photoshop processes. Some have been turned off while alternate techniques are tried or simply to isolate bugs.

The actions needed to achieve the final look. Each line is a photoshop process.

I soon learned why the commercial tools used simple etching patterns. Mimicking a hand drawn look is impossible without some way to simulate the artists constant decision-making – changing line based on the subjects topology – and looks like little more than a generic filter. The images below where actually created using the easier, quicker method of the multilayered grayscale texture. It proved a good way to test ideas. They also show the two styles: that of crosshatching with positive, black lines, on a white ground – like drawing; and the other of taking negative white lines from a black ground – like a scratch board. In the many period examples we have there seems to be a good mixture of both.

Early tests of multi-layered grayscale patterns

So I gathered in my pride and created a number of generic mechanical patterns I could use as a starting point for the more complicated approach. Like the first commercial tool, these are too mechanical and perfect for what I eventually want but they’re a good way to gain an understanding of how they interact and how different shades are being represented. Unlike the real world approach, I have practical limitations forced on me by pixel sizes. A black line can only be a minimum of 1 pixel which then gets anti aliased to 3. Getting the right ratio of line thickness to white space to provide enough options while keeping the scale of the pattern to the size I wanted and keeping moiré (visual interference patterns) to a minimum .. proved somewhat tricky.

A collection of etching patterns. Don’t look at these full screen for too long!

Using these I now get headaches, nausea, blurred vision and these kinds of results: Left is the original, centre a positive black line version and the right is an early experimental negative white line alternative.

An image after being put through the etching process.

An original photo that has been etched and colored.

While there’s still room for more subtlety this is the current tonal range I’m using.

A photo of the actual Gettysburg battlefield as it looks today (minus the cars, signs and road), recreated using the etching process.

Since period and modern photos come in a wide variety of qualities and tonal ranges the action also accounts for this by equalising their tones and density of high and low-frequency detail. That means the etching process always starts with a relatively level playing field and is predictable. I can also work on images of exactly the size I need without having to reduce or enlarge and so compromise the final quality of line.

It’s not there yet. It still looks mechanical and lacks the implied artistic decision making. I have managed to suggest it to a degree but it required tools and several extra steps external to Photoshop. This needs to be a one program, preferably one click, solution.

Pat mentioned that this is still quite a work in progress and they will continue to experiment with this really interesting idea. This etching process will allow us to use a wider range of images, it really is a major breakthrough by our art team. Please stay tuned for further updates on Gettysburg: The Tide Turns.

(Note: Originally Published on the Shenandoah Studio Blog)