In days of yore, printing technology required creative ways to make photos look realistic. One such method was halftone. Popular in comic books and newspapers, halftone was economical and innovative, and is still used today for a faux vintage effect. Let’s look at halftone and the challenges it presents to photo enhancement.
What Is Halftone?
Halftone is a way of printing that tricks the eye into recognising shades and gradients. Whereas we are used to a continuous flow of shades, halftone creates an optical illusion for a similar (albeit less detailed) result. Take a look at an old newspaper and see how the black and white photographs are printed. At a glance they’re quite convincing. Look closer, however, and you’ll see the photo is made from clusters of black dots. The size and density of these dots dictate whether the shaded area will be darker or lighter.
Enhancing a Halftone Photograph
If a halftone photograph is just a series of dots, how do we go about restoring it? Yes, you can reach for your Patch tool and fill in the blanks as usual. You have to be pinpoint precise with this: large selections will leave an indecipherable blob of dots that make no sense to the surrounding areas. What happens when the subject is swathed in dots and does not stand out from the background, like the girl to the top right of this photograph? Her hair happens to match the tree in the background, as does the boy’s shirt with the surrounding sky.
Instinct tells us to put a blanket filter on it: a good gaussian blur could merge the dots into one another, right? While this is true of some photos, our example would look smudged as the dots are simply too dense in detailed areas.
The thing is, what do we want from this photo? Are we looking for a crisp view of every leaf, or is it important to see the family front and centre? The latter makes more sense, so we obscure the background, applying a motion blur filter and brightening the sky and tree line. In contrast, the family become the undisputed centrepiece of the photo. While on the one hand you’ve created a flatter effect by lifting one layer from another, you have a photo whose subject is clear.
I don’t believe old image enhancement is always about absolute photorealism. While that’s true for archival purposes, in this case it’s about embellishing the important aspects of the photo. An effect such as this is arguably better on the mantelpiece than something with a darker, intact background.
By Bruce Sigrist in: Discussion