How Artists Paint Comuna 13’s Giant Murals

Large walls begin with logistics

Before color goes up, artists need access, surface condition, permission, materials and a way to reach height safely. Retaining walls and infrastructure surfaces can require scaffolding, ladders or lifts. Weather and pedestrian flow matter in a dense neighborhood.

Design moves from small to huge

Artists may use scaled sketches, grids, projection, reference marks or freehand construction to transfer a composition. The larger the wall, the more important proportions become because the artist cannot see the whole image from arm’s length.

Spray paint is only one tool

Rollers and brushes are efficient for large fills and backgrounds; spray cans excel at edges, fades, line work and lettering. A wall that tourists call “graffiti” may have been produced with several techniques.

Collective murals add coordination

The 370-square-meter “Somos Comuna” work was described by Medellín as a collective process between urban artists and residents under the direction of Pictopia Medellín. Collaborative projects require decisions about visual language, division of wall space and how community input becomes imagery.

Finishing does not make the work permanent

Outdoor paint degrades. Buildings change. Businesses add signs. Other artists may later paint the surface. Documentation and artist attribution are therefore part of the production story too, especially for culturally significant work.

Field notes and deeper context

Why wall preparation matters Concrete can be dusty, cracked, damp or previously painted with incompatible coatings. Cleaning, patching and priming determine whether a mural stays legible through Medellín’s rain and sun. Large public projects may also need traffic or pedestrian management so artists can work without creating hazards. These invisible preparation steps are a major reason a professional commission looks different from a quick unsanctioned intervention. Watch process when you get the chance If artists are actively painting, give them space. Observe how one person handles broad fills while another develops line work or details. Notice the constant stepping back to judge proportions from a distance. A finished mural can make a huge wall seem effortlessly designed; seeing the process reveals how much physical labor, planning and correction are involved.

The wall is a construction problem before it is an art problem

A giant mural begins with access. Artists need to know the wall’s dimensions, material, cracks, moisture, slope, nearby cables, traffic and whether ladders, scaffolding, lifts or rope access are possible. In Comuna 13, steep terrain and narrow pedestrian routes can make logistics as important as drawing skill.

A clean digital mock-up does not reveal those constraints. A retaining wall may have irregular concrete seams. A brick facade absorbs paint differently from a sealed surface. A wall that looks flat from the street may be reachable only from terraces or stairs.

Large commissioned projects therefore involve site visits, permission and technical planning before the first color is applied. Medellín’s institutional urban-art programs now explicitly include technical evaluation and curated selection, reflecting how professionalized the field has become.

Surface preparation determines whether the mural lasts

Loose paint, dust, algae and moisture can ruin adhesion. Depending on the wall, artists or production crews may scrape, clean, patch cracks and apply a primer or base coat. A uniform base also helps colors read consistently.

This matters in a tropical mountain city. Sun, rain, humidity and pollution all work on the surface. A wall exposed to hard afternoon sun ages differently from one protected by an overhang. Drainage can matter as much as pigment quality.

For a visitor, this is worth noticing because “fading” is not always an artistic decision. It can simply be material weathering.

A small design has to be transferred to architectural scale

Artists have several ways to enlarge a sketch. A grid divides both the reference and the wall into corresponding sections. Projectors can be useful on accessible surfaces and in controlled light. Some muralists freehand major shapes from measured landmarks. Others use chalk lines, snapped guides or plotted points.

On a 370-square-meter wall such as Somos Comuna, proportion errors compound quickly. A letter that is ten centimeters off in a sketch may become a meter-scale problem when enlarged. Large work therefore rewards planning and the ability to step far enough back to judge the composition.

Background, blocks and details are usually painted in layers

Large areas often come first: base colors, sky, fields, geometric shapes or broad letter fills. Rollers and brushes move paint efficiently across square meters of surface. Spray paint becomes valuable for gradients, crisp outlines, shadows, lettering, texture and corrections.

Artists may work simultaneously on different sections. That requires a shared palette and clear decisions about edges, overlaps and visual hierarchy. A collective mural is partly an exercise in project management.

Graffiti lettering has its own technical logic

Lettering is not simply text placed on a mural. Writers think in terms of letter skeletons, weight, spacing, connections, outlines, fills, highlights and extensions. A name must hold together from a distance while retaining the writer’s style.

Medellín’s description of Somos Comuna is notable because it foregrounds graffiti lettering rather than treating it as decoration. That makes the work useful for seeing how a writing tradition can scale into a major civic intervention.

Collective murals add community decisions

When residents participate, the design process can involve workshops, interviews, symbol selection or review sessions. The result may intentionally combine several visual languages. Authorship becomes layered: there can be a lead art team, individual painters, community contributors, an institutional commissioner and a wall owner.

This is one reason it is risky to attribute a collaborative wall to the most famous name associated with it. Check the project record.

The painting day is only the visible part of the job

A large mural may require traffic control, material staging, meals, weather contingencies, equipment rental, documentation and cleanup. City-supported projects may also involve insurance, occupational-safety rules and agreements about maintenance.

Medellín’s Latidos biennial, which began in 2025, is evidence of this professional ecosystem. It involved large-format works, curated artists, training, festivals and thousands of square meters of intervention. Graffiti and muralism here are not only spontaneous acts; they also function as organized cultural production.

Why giant murals eventually change anyway

Even a carefully prepared mural is not permanent. UV light fades pigments. Water finds cracks. New construction blocks sight lines. Businesses alter facades. Artists repaint. Public agencies renovate infrastructure.

That impermanence is part of the medium. The interesting question is not merely “how long will this last?” but “who decides what happens to the wall next?”

What you can infer by looking closely at the finished wall

Tool marks survive in the image. Roller texture often appears in broad flat fields. Spray paint can produce soft gradients, sharp lines, fades and misted edges. Brushwork can show up in organic shapes and small corrections. Drips may be intentional or simply evidence of fast application.

Look at seams and corners too. If an image wraps around an architectural edge cleanly, the artist planned for multiple viewpoints. If outlines drift slightly across rough concrete, the surface itself may have dictated the result. Large murals are negotiations with architecture, not enlarged digital illustrations pasted onto perfect rectangles.

Photographs from far away hide much of this labor. Standing a meter from the wall is where you see how physical the process really is.