A Practical Guide to Cross-Polarisation Photography

Cross-polarisation (or “cross-pol”) is a photographic technique where two polarising filters – one on the light source and one on the camera – are set at 90° to each other. When aligned correctly, the filters eliminate specular reflections and can reveal birefringence patterns in certain materials.

This guide walks you through exactly how to do it, using both studio and DIY setups.

1. Understanding the Core Concept

Light waves vibrate in all directions. A polarising filter only lets waves through that vibrate in one direction.

Polariser A (on the light): Makes the light “uniform,” allowing only one vibration direction.
Polariser B (on the lens): Blocks that direction and only passes waves vibrating 90° to it.

When the two filters are crossed, reflections vanish—but internal stress patterns inside transparent plastics glow with vivid colours.

Think of it as cancelling the surface glare so you can see the hidden interior world.

2. What You Need

You don’t need a fancy studio. Here are options for every budget:

Essential Equipment

A camera (phone, mirrorless, or DSLR)
A polarising filter for the lens
- Circular polariser (CPL) for most photography
A polarising sheet for your light source
- Linear polarising film is inexpensive and sold in A4 sheets

Optional but helpful

Two or more small LED panels (or even tablet screens)
Diffuser (white fabric or tracing paper)
Tripod (recommended)
Black background

3. Setting Up the Cross-Pol Lighting

Step A: Polarise your light

Place the polarising sheet in front of your light source.
If your light produces hotspots, add a diffuser behind the polarising film.
Make sure the polarising film covers the light completely – any uncovered portion will leak unfiltered light into your shot.

DIY tip:

A tablet or phone screen already emits polarised light – great for photographing small plastics like cutlery or toys.

4. Prepare Your Camera

Attach the CPL to your camera or phone adapter.
Point the camera at the polarised light.
Rotate the CPL slowly.

You’ll notice the light visibly darkening when the two polarisers reach a 90° relationship.

This is your cross-polarisation achieved.

5. Shooting Techniques

A. For Stress-Pattern Photography

Used with clear or translucent plastics.

Place the plastic object between the light and the camera.
Cross the polarisers (maximum black).
Increase exposure slightly to compensate for light loss.
Fine-tune the angle of the object – some stress patterns appear only at certain orientations.
Use a black or very dark background to intensify colours.

Common objects that reveal stunning patterns:

Sunglasses
Water bottles
Tape dispensers
Plastic spoons
Acrylic sheets

B. For Reflection-Elimination Photography

Used for glossy surfaces, jewellery, metal, and liquids.

Position your subject so the polarised light hits it at ~45°.
Rotate the CPL until reflections disappear.
Adjust your lighting angle if you see “patches” of unpolarised reflections.

This is extremely useful for product photography.

6. Exposure and Camera Settings

Cross-pol setups reduce the amount of light reaching the sensor. To compensate:

Increase ISO moderately (200–800)
Use longer shutter speeds (especially with tripod)
Open your aperture (f/2.8–f/5.6 works well)

Avoid raising ISO too high, as cross-pol images often contain smooth gradients where noise becomes visible.

7. Compositional Tips

Use backlighting for the strongest birefringence effects.
Rotate the subject slowly – stress colours shift dramatically.
Try using two polarised lights for symmetrical objects.
For artistic images, place multiple plastic objects overlapping to create abstract colour fields.