Camille Mercier

Rule of Thirds

A composition principle that divides the image into 9 equal zones with 2 horizontal and 2 vertical lines. Placing important elements on these lines or at their intersections creates a more dynamic and balanced image.

Leading Lines

Natural or architectural lines that guide the viewer's eye toward the main subject. A line reads as a guide once it covers 20-30% of the frame diagonal: roads, fences, rivers, shadows, lines of sight.

Golden Ratio

Mathematical ratio φ ≈ 1.618 used in composition to divide the frame into harmonious zones. A simplified cousin of the rule of thirds, it guides the placement of subject and lines of force.

Visual Balance

The sense that an image "holds" — the perceptual center of gravity falls within ~10% of the geometric center, or at a deliberate offset the frame justifies. A perceptual matter before a geometric one: a small high-contrast detail can balance an entire half of bright sky.

Negative Space

Empty — or perceived-as-empty — zones surrounding the subject, typically 50 to 80% of the frame depending on the intent. Uniform sky, smooth wall, fog, blur. An intentional choice about what is NOT there, not a default of what's missing.

Vanishing Point

Theoretical point where parallel lines of a subject in perspective converge. It structures the sense of depth and inherits from the geometric perspective of Brunelleschi (1413) and Alberti (De Pictura, 1435).

Frame within a Frame

Composition technique that uses an architectural or natural element — doorway, arch, window, branches — as a secondary frame around the subject. It reads as enclosure when it surrounds the subject on at least two adjacent sides. Hierarchizes, contextualizes and adds depth in a single move.

Symmetry

Regular correspondence between elements of an image around an axis or center, with the eye tolerating no more than ~1° of angular deviation. Three families: bilateral, radial, reflection. A tool for stability and monumentality.

Golden Triangle

Diagonal composition grid: a corner-to-corner diagonal, two perpendiculars from the opposite corners, and four power points arranged on the diagonal. Ideal for oblique scenes.

Repetition and Rhythm

Identical or near-identical motifs (repetition, typically 3-5+ occurrences) and the visual cadence they create (rhythm). Breaking the pattern produces a remarkably effective focal point.

Depth

The sense of three-dimensionality in a photo, built from at least three identifiable planes (foreground 0.5-2 m, subject, background) plus perspective and atmospheric haze. Not to be confused with depth of field.

Color Harmony

A balanced combination of colors built on the color wheel, classically organized around a 60/30/10 ratio (dominant / secondary / accent). Three main families: complementary, analogous, monochromatic.

Distracting Elements

Unwanted objects or details that pull attention away from the main subject — anything holding the eye more than half a second on first pass: power lines, background people, reflections, elements clipped at the frame edge.

Landscape / Portrait Format

Horizontal (landscape, width > height) or vertical (portrait, height > width) orientation. Choice driven by composition and intent, not by the subject.

Cropping

Cutting a rectangular portion of the original file in post. Aim to keep at least 70% of pixels for a clean A4 print, never go below 50% before grain shows. A second-chance tool, not a substitute for in-camera framing.

Aspect Ratio

Width-to-height ratio of an image. 3:2 (Leica 1925), 4:3 (smartphones, MFT), 1:1 (Hasselblad, early Instagram), 16:9 (cinema), 4:5 (Instagram portrait), 9:16 (Reels), 65:24 (Xpan).

Portrait Photography

Genre centered on a person, capturing features and character. Subgenres: posed (Avedon, Penn), environmental (Newman, Leibovitz), documentary (Lange Migrant Mother 1936), street (Vivian Maier).

Landscape Photography

Genre whose subject is the environment (natural or urban) spread in depth. Subgenres: classical (Ansel Adams Yosemite 1927, Group f/64), intimate (Caponigro), cityscape (Gursky Rhein II 1999), minimalist (Kenna).

Street Photography

Spontaneous photography of ordinary moments in public spaces. Forefathers: Cartier-Bresson (Saint-Lazare 1932, decisive moment), Doisneau, Winogrand, Vivian Maier (revealed 2007), Daido Moriyama.