Filters are glass or resin placed in front of the lens to modify light before it reaches the film. Unlike digital post-processing, filtration happens at capture — effects are baked into the negative.

This guide covers the essential filters for film photography: what they do, when to use them, and how to expose with them.

Why Filters Matter More for Film

Digital photographers can often replicate filter effects in post-processing. Film photographers can't. What you capture is what you get.

Effects that can only be done with filters:

Polarisation (can't be added later)
UV haze reduction (already recorded)
Long exposure ND effects (motion blur is captured)
Colour correction (affects how film records colours)

Effects easier done with filters:

Graduated ND (cleaner than compositing)
Colour warming/cooling (avoids scanning adjustments)
Infrared (requires IR-blocking filter removal otherwise)

UV and Haze Filters

UV Filters

UV filters block ultraviolet light, which can cause haze and blue casts in film — especially at altitude or near water.

When useful:

Mountain photography (UV increases with altitude)
Beach/water scenes (UV reflects off water)
Distant landscapes (atmospheric haze)

When not needed:

Modern multicoated lenses block most UV already
Overcast conditions
Indoor/controlled lighting

Many photographers leave UV filters on permanently as lens protection. This is fine with quality filters, but cheap filters degrade image quality.

Skylight Filters

Similar to UV but add slight warming (pink tint). Traditionally used to counteract cool shade and overcast light with slide film. Less relevant now that colour correction is easy in scanning.

Note

A quality UV filter (B+W, Hoya HMC, Nikon NC) adds minimal degradation and protects against scratches and impacts. A cheap filter adds flare, reduces contrast, and affects sharpness. If you use protection filters, invest in good ones.

Polarising Filters

Polarisers control reflections and enhance colour saturation. They're essential for film photographers because their effects cannot be replicated in post.

How Polarisation Works

Light waves vibrate in all directions. When light reflects off non-metallic surfaces (water, glass, foliage), it becomes partially polarised — waves align in one direction. A polarising filter blocks light vibrating in a particular plane.

Effects of Polarisation

Darkened blue sky: Atmospheric polarisation makes the sky darkest at 90° from the sun. Maximum effect at sunrise/sunset looking perpendicular to the sun.

Reduced reflections: Reflections off water, glass, and wet surfaces can be removed or reduced. Angle matters — effect is maximum at about 35° from the surface.

Enhanced saturation: Reducing surface reflections on foliage increases colour saturation. Leaves appear richer green; autumn colours pop.

Cut haze: Polarised light contributes to atmospheric haze. Filtering it improves distant clarity.

Circular vs Linear

Linear polarisers: Simpler, cheaper. Can confuse autofocus and metering on some cameras.

Circular polarisers (CPL): Have an additional quarter-wave plate that maintains compatibility with AF and metering. Use circular unless your camera is fully manual.

If you're unsure whether to buy circular (CPL) or linear, get circular — it works on all cameras.

Exposure Compensation

Polarisers absorb light. Typically 1.5-2 stops. Through-the-lens metering accounts for this automatically, but handheld meters require manual compensation.

Using a Polariser

Attach filter and look through viewfinder
Rotate the front element while watching the effect
Stop at desired polarisation level
The effect varies — rotate to find the sweet spot
Maximum effect is not always best; partial polarisation often looks more natural

Warning

Ultra-wide lenses (24mm or wider on 35mm) can show uneven polarisation — one side of the sky darker than the other. This is because different parts of the frame are at different angles to the sun. Use polarisers carefully with wide angles or accept the effect.

Neutral Density Filters

ND filters reduce light without affecting colour. They enable slower shutter speeds or wider apertures in bright conditions.

ND Filter Strengths

Filter	Density	Light Reduction	Use
ND2	0.3	1 stop	Minor reduction
ND4	0.6	2 stops	Open aperture one step
ND8	0.9	3 stops	Slow handheld in bright light
ND64	1.8	6 stops	Motion blur in daylight
ND1000	3.0	10 stops	Long exposure in full sun

When to Use ND Filters

Motion blur in daylight: Waterfalls, streams, waves, clouds — all benefit from long exposures. Without ND, bright conditions force fast shutter speeds.

Wide aperture in bright light: Want f/1.4 portraits at midday? ISO 100 film maxes out around 1/1000 at f/2.8 in bright sun. ND lets you open up further.

Long exposures for effect: Multi-minute exposures smooth water, erase people from crowded scenes, and create ethereal effects.

ND and Reciprocity

Very long exposures require reciprocity compensation — the film becomes less sensitive at long exposure times. Different films have different reciprocity characteristics.

Example: With a 10-stop ND, a 1/30 base exposure becomes 30 seconds. With Acros II (minimal reciprocity), use 30 seconds. With Portra 160 (significant reciprocity), you might need 1-2 minutes.

See our reciprocity calculator for film-specific adjustments.

Graduated ND Filters

Graduated ND (GND) filters are half clear, half neutral density with a gradual transition. They balance exposure between bright skies and darker foregrounds.

Types of Graduates

Hard edge: Abrupt transition. Best for flat horizons (seascapes).

Soft edge: Gradual transition. Better for uneven horizons (mountains, trees).

Reverse grad: Darkest at the centre, lighter toward the top. Good for sunsets where the horizon is brightest.

Using Graduated Filters

Compose your shot
Hold the filter in front of the lens
Adjust the filter position so the dark area covers the bright sky
The transition should align with the horizon (roughly)
Meter for the foreground; the filter handles the sky

Slots vs Screw-In

Screw-in GNDs: Convenient but transition is fixed at centre of frame. Limited flexibility.

Slot systems (Cokin, Lee, NiSi): Holder attaches to lens; filters slide up and down. Allows positioning the transition anywhere. More versatile but more gear.

Note

Graduated ND works best with straight horizons. If your scene has trees, buildings, or mountains breaking the horizon, the dark graduation covers them unnaturally. Consider exposure blending in scanning instead, or accept the limitation.

Colour Correction Filters

Colour correction filters adjust colour temperature and tint. They're most important for slide film, which can't be colour-corrected later.

Warming and Cooling

81 series (warming): 81A, 81B, 81C add increasing warmth. Counteract blue shade or overcast light.

82 series (cooling): 82A, 82B, 82C add blue. Counteract warm indoor lighting (rarely used).

85 series: Convert daylight film for tungsten light. 85B is standard for tungsten-to-daylight conversion.

80 series: Convert tungsten film for daylight. 80A is standard.

When to Use Colour Correction

Slide film: Colour correction is critical. Daylight slide film in shade goes blue; under tungsten goes orange. Filters are the solution.

Colour negative film: Largely unnecessary. White balance adjustments in scanning handle most colour casts. Extreme situations might benefit.

Black and white: No colour to correct, but see contrast filters below.

Contrast Filters for Black & White

Coloured filters dramatically affect how black and white film renders tones. They lighten their own colour and darken complementaries.

How It Works

A red filter passes red light and blocks blue/green. Red objects reflect more light, appear lighter. Blue sky reflects less light, appears darker.

Common B&W Filters

Filter	Effect on Sky	Effect on Foliage	Use
Yellow	Slightly darker	Slightly lighter	Natural look, clouds pop
Orange	Darker	Lighter	Strong sky, good skin tones
Red	Very dark, dramatic	Light	Very dramatic, high contrast
Green	Unchanged	Lighter, separated	Nature, foliage detail
Blue	Lighter	Darker	Creative effect, delicate tones

Classic Uses

Yellow filter: The standard outdoor filter. Darkens blue sky to make clouds visible. Natural-looking tonal separation. Minimal exposure compensation (about 1 stop).

Orange filter: More dramatic sky darkening. Good for architecture, landscapes with sky. Flattering skin tones in portraits. About 2 stops compensation.

Red filter: Very dramatic. Near-black skies, bright clouds, infrared-like effects. Can look unnatural but striking. About 3 stops compensation.

Green filter: Separates foliage tones — different greens render as different greys rather than one mass. Good for nature photography. About 2 stops compensation.

Warning

Coloured filters absorb light. TTL metering usually compensates automatically, but check your camera manual. Handheld meters require filter factor compensation: a 2x filter needs +1 stop, 4x needs +2 stops, 8x needs +3 stops. In other words, a filter factor of 2x means +1 stop; 4x means +2 stops. Double the factor = add one stop.

Filter Quality and Care

Quality Matters

Cheap filters degrade image quality: flare, reduced contrast, colour casts, reflections. Invest in quality:

Recommended brands:

B+W (German, excellent quality)
Hoya (Japanese, good value)
Heliopan (German, excellent quality)
NiSi (newer, good quality slot system)
Lee (UK, industry standard slot system)

Avoid:

Unbranded filters
Very cheap "kit" filters
Old, scratched, or coated filters

Care and Storage

Handle by edges, never touch glass
Clean with microfibre cloth and lens cleaner
Store in protective cases
Check for scratches and coating damage
Replace degraded filters — they're cheaper than re-shooting

Practical Filter Kits

You don't need many filters. A minimal kit covers most situations:

For Colour Film

Essential:

Polariser (circular if using AF cameras)
ND8 or ND64 for long exposures

Optional:

Graduated ND (soft edge)
81A warming filter (for slide film in shade)

For Black & White