The Science of Ocean Colours: Why Water Changes Hue and What It Means

Ocean Colours: A Photographer’s Guide to Capturing Sea HuesCapturing the sea’s colours is both an art and a science. The ocean can present an endless palette — turquoise shallows, inky blues, jade greens, and steely greys — all changing with light, weather, depth, and life beneath the surface. This guide explains why the sea looks the way it does, how to anticipate and control colours in-camera, and practical techniques to create powerful, evocative ocean images.

Why the ocean changes colour

The sea’s colour is determined by several interacting factors:

• Light and angle: Sun position, time of day, and viewing angle alter colour through scattering and reflection. Low-angle sunlight (golden hour) warms tones; midday sun favors saturated blues.
• Water depth and bottom: Shallow water over sand or coral reflects those colours (turquoise or aquamarine). Deeper water absorbs longer wavelengths, shifting toward deep blue.
• Particles and organisms: Plankton, sediment, and dissolved organic matter influence colour — blooms of phytoplankton can turn water greenish; suspended sediment can make it brown or ochre.
• Sky and weather: The ocean often mirrors the sky. Overcast days mute hues; clear skies intensify them. Wind and waves change reflectivity and specular highlights.
• Chemical composition: Salinity, dissolved organic compounds, and minerals can subtly affect hue and clarity.

Understanding these causes helps you predict the palette and decide how to capture or enhance it.

Gear and settings to prioritize

Camera and lens choices, plus the right exposure approach, let you control how ocean colours read.

• Use a camera with good dynamic range to retain detail in highlights and shadows.
• Lenses: wide-angle for seascapes; telephoto for isolating colour patches or distant bands; macro for details like foam, algae, or water droplets. A polarizer and neutral-density (ND) filters are often essential.

Suggested starting settings:

• Shoot RAW for maximum colour and exposure flexibility.
• ISO: keep as low as possible (100–200) to preserve colour fidelity.
• Aperture: f/8–f/11 for landscape sharpness; wider for low light or shallow depth when isolating details.
• Shutter speed: fast (1/500s+) to freeze spray; slow (1/2s–2s) or longer with ND for silky water.
• White balance: Auto can work, but custom or preset (Daylight/Cloudy) gives consistent colours. Fine-tune in RAW.

Using filters to manage reflections and colour

• Polarizing filter: reduces reflections on the water’s surface and deepens blues and greens — rotate until you get the desired effect. Note: polarizers are most effective at 90° to the sun and can unevenly darken wide-angle skies.
• Graduated ND filter: balances bright sky and darker sea; useful at sunrise/sunset when horizon contrast is high.
• Neutral-density (ND) filter: enables long exposures to smooth water and reveal colour bands without overexposure.

Composition tips for stronger colour impact

• Layering: Use shoreline, bands of water depth, surf lines, and distant horizons to create horizontal colour bands.
• Foreground interest: Rocks, seaweed, tide pools, or wet sand reflect and amplify colour. Close foreground elements provide texture and scale.
• Minimalism: Negative space—large areas of a single hue—can be powerful if tones are rich and subtle.
• Leading lines: Wave breaks, foam lines, or currents guide the eye through colour transitions.
• Reflections: Look for glassy water or wet stones that mirror sky hues for doubled colour effects.

Examples:

• Tropical shallow reef: shoot low and close to reveal turquoise over sand; include coral or snorkeler for scale.
• Stormy ocean: emphasize slate greys and teal highlights; use a telephoto to compress distance and intensify layers.
• Arctic or polar seas: capture muted blues and aqua with high-contrast ice forms to add structure.

Light and timing: when colours sing

• Golden hour (sunrise/sunset): warm, rosy highlights on water; enhances contrast between warm sky and cool water.
• Blue hour (pre-dawn/post-sunset): deep, cool tones ideal for moody, minimalist seascapes.
• Midday: intense blues under clear skies; best for saturated tropical shots if you manage reflections with a polarizer.
• Overcast/stormy: diffused light reduces harsh reflections and can emphasize subtle tonal transitions and texture.
• After rain or during changing weather: transient colour combinations appear as clouds shift and sunlight breaks through.

Post-processing: faithful enhancement, not fabrication

Post-processing should enhance natural colours while avoiding unrealistic shifts unless that’s your creative intent.

Workflow essentials:

1. Start in RAW: recover highlights/shadows and adjust exposure without degrading colour.
2. White balance: fine-tune to match scene mood (warmer for sunrise, cooler for blue hour).
3. Contrast and clarity: increase contrast to give depth; use clarity or texture carefully — too much can make water look artificial.
4. HSL adjustments: selectively boost saturation or luminance of blues and cyans to make ocean tones pop; reduce greens or yellows if sediment or algae create unwanted colour casts.
5. Graduated adjustments: darken skies or lift shadows locally to balance the scene.
6. Noise reduction and sharpening: preserve smooth gradients in water; avoid over-sharpening foam or smooth surfaces.

Example Lightroom settings (starting point): Exposure +0.1–0.3, Contrast +10–20, Highlights −20 to −50, Shadows +10–30, Whites +5–15, Blacks −5–15, Clarity +5–15, Vibrance +10–25. Adjust Hues: Blues −5 to +5, Saturation (Blues/Cyans) +10–25, Luminance (Blues/Cyans) +5–20.

Creative techniques and projects

• Long-exposure abstracts: use ND filters to blur water into smooth gradients; focus on colour bands and minimal shapes.
• High-contrast black-and-white with colour accents: desaturate most of the scene while keeping a strip of blue or turquoise for dramatic effect.
• Time-lapse of changing ocean colours: capture hourly frames to show shifts with light and weather.
• Macro studies: photograph water droplets, foam patterns, or algae to reveal micro-palettes.
• Drone perspectives: aerial shots reveal reef patterns and wide colour mosaics not visible from shore.

Troubleshooting common issues

• Washed-out colours: check white balance, underexposure recovery limits, or polarizer overuse. Increase saturation/vibrance selectively.
• Uneven sky darkening with polarizer: reduce polarizer rotation or switch to spot polarizing (use circular polarizer carefully with wide lenses).
• Colour banding in gradients after heavy edits: reduce extreme contrast adjustments; increase bit depth when exporting where possible.
• Reflections blocking underwater detail: use polarizer and shoot at an angle; for total surface reflection, embrace it as an abstract element.

Practical field checklist

• Camera + charged batteries + memory cards
• Wide, standard, and telephoto lenses (or a versatile zoom)
• Circular polarizer + ND + graduated ND filters
• Tripod with sturdy legs (for long exposures)
• Lens cloth and protective gear (salt spray, sand)
• Notebook or phone for weather/tide notes
• Waterproof bag and safety gear

Final thoughts

Mastering ocean colours combines observation, timing, and technical control. Learn how light, depth, and biology affect hue, practice with filters and exposures, and develop a post-processing workflow that enhances without overselling. Over time you’ll see the ocean not just as “blue,” but as a living spectrum ready to tell countless visual stories.