In our series Sticks & Stones, we take a deep dive into medium. Each installment features one of art history’s most significant materials—its history, evolution, and unusual uses. (See past installments.) This week’s medium is Photoshop (explore the playlist).

As the cultural definition of what constitutes fine art widens every year, new materials and techniques are continually added to the artist’s toolbox. In the past decade (or so), Adobe Photoshop in particular has become a crucial element of many contemporary artists’ practice—and not just photographers. The program, now available across multiple devices and operating systems, is one of those rare products that transcends brand status; it has even become a noun and a verb. ‘To Photoshop’ is now synonymous with ‘to alter’ or ‘to fabricate’ when referring to photographic images. And yet, the history of tampering with photos stretches back much further than 1987, when Photoshop was first invented.

Almost from the moment photography was introduced to the public, it was presented in altered states. The common darkroom procedures of ‘burning in’ or ‘dodging out’ adjust the amount of light a print absorbs, darkening or lightening specific areas from the negative. These kinds of techniques allow photographers to correct exposure errors, or create more dramatic contrasts—but sometimes they are not enough. For example, an early photographer attempting to capture a landscape scene might take two separate photographs with different settings, one to capture the sky and another to capture the land, and then print the two negatives into a single composite photograph. (Even more bizarrely, group portraits were commonly shot individual-by-individual, and then amalgamated in the darkroom.)

Critics of photography derided what they saw as an absence of creativity from the medium. The idea that photography was no more than a mechanical process was hotly contested by many in the field, especially those who experimented widely to see what kinds of otherworldly, ethereal illusions they could create in the dark room. This experimentation flourished under the influence of the Surrealist movement, and photographers like Dora Maar, Angus McBean, and Man Ray were able to create photographs that were almost painting-like in their manipulated design. Their insistence on viewing the photograph not as a static, immutable depiction of reality, but as a flexible and constructable scrim, furthered the thinking that would create a space for Photoshop to reign.

The first computer program for manipulating photographs was invented in 1987, and was rapidly embraced by media outlets and advertisers. In 1990, Adobe Systems released Photoshop 1.0. While it was initially intended for graphic designers, the new program was adopted by artists and photojournalists, who were excited by the notion of having greater creative control over their work. At the heart of the program are two major elements: layers and masks. To visualize how exactly images are digitally altered, imagine layers of acetate being laid over an existing image, to conceal or superimpose an element, or to alter the quality of what is seen through it (e.g. to tint or blur). While most professional photographs we see today are Photoshopped to some extent, Photoshop has also had a significant impact on how visual artists outside of photography think about layers and planar space.

Today, we’re used to seeing Photoshopped images—it’s hard to find a single “pure” advertisement—and so have become skilled at spotting the signs of photographic altering. There are telltale signs that a painting, drawing, or print has been designed and composed in Photoshop as well, if you know what to look for. Photoshop has given contemporary artists a flexible approach to layers; a complex depth of field in an image is often a sign that Photoshop was used in its composition. The illusion of stacked space punctuated with cutaways, in the work of artists such as Albert Oehlen, Kerstin Brätsch, or Laura Owens, is a direct nod to the modern software and its pictorial organizing capabilities.

Photoshop is a prime example of emerging media not only as a new creative option for artists, but also as tool to expand upon existing techniques and knowledge. It is used in the studios of all major artists, whether they’re using it to create digital art, or they’re just enhancing existing work. Art has long co-opted the by-products of other industries to use for its own means, and, as the world becomes increasingly digitized, unimaginable opportunities lie ahead.