Halftone Print: an Optical Illusion

If you zoom in on the photos that you come across on your smartphone, you will find that you see tiny squares that make up the image. Today, these tiny squares of color that make up what seems to be a seamless image are referred to as pixels. They are tiny cubes of color, organized to come together and create a meaning. Even the words we see typed out on this screen are made up of pixels.  Looking at how far technology has come, we can see how early imaging technology paved the way for the advanced image quality seen all around us.

In 1852, William Talbot pioneered the use of a screen, consisting of a grid of holes for ink to pass through, to create an intentional pattern. This technique, known as halftone printing, was used to print black dots, varying in distance apart, size and shape to create an image that appears to have dimension, shadows and detail. For example, black dots that are closer together may be used to create the darkest part of an image, while distant dots create a lighter effect. The most common type of printing used today, will only print one color of one tone, or no ink at all, though it may seem to appear lighter in some areas. There are currently three types of halftone printing: conventional, stochastic and color/moire. Conventional printing consists of printing in which the dots vary in size, but not distance between the center of each dot. Stochastic printing consists of dots that are randomly places in no pattern or certain distance apart. The dots may also be different sizes. Meanwhile, in color printing, the overlap of a few basic colors is used to create more colors, and therefor portray an image more similar to what we see in real time.

Check out the image below. As one of the earliest images created using the screen halftone process, it appears that the dots vary in size and distance apart. Doesn't the hand look closer to you than the rest of the image? That is a result of lack of ink, used in a way that creates depth. Now, go into your phone and look at an image with depth. Upon zooming in, you will notice that the depth is created by clarity in the image, meaning more pixels to create more detail in the foreground of the photo. This technology began with half toning and will continue to evolve. Also, the better the printer, the better the image quality, so maybe one day the images we print will be as clear as the photo on the screen!