Knowing how to test paint colours properly is honestly the difference between loving your walls and wanting to cry every time you walk into the room.
That shade that looked perfect on the tiny chart? It can look completely different once it’s actually on your wall. Trust me, I’ve been there. So here’s how to test paint the right way — so you don’t end up repainting a week later.
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Why You Need to Test Paint Colours Properly
This is exactly why you need to test paint colours properly before committing. The colour you see on a tiny swatch in a brightly lit shop is not the colour you’ll see on your wall at home.
Your lighting is different. North-facing rooms get cool, blue light. South-facing rooms get warm, yellow light. Artificial lighting changes colours again. The same paint can look completely different depending on your room’s light.
Colour is affected by surroundings. Your flooring, furniture, and even the colour of nearby walls can influence how a paint colour appears. A warm beige next to a cool grey sofa will look different than next to a warm wooden floor.
Undertones reveal themselves on walls. That ‘neutral’ you picked might have pink, purple, green, or yellow undertones that only become obvious once it’s on a large surface.
Paint changes as it dries. Wet paint looks different to dry paint. You need to let it fully dry before judging the true colour.
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Swatch Cards vs Tester Pots: Which Should You Use?
Both have their place — but they serve different purposes.
Swatch Cards
Best for: Initial shortlisting. Comparing multiple colours quickly. Getting a sense of undertones.
Limitations: Small size doesn’t show how colour will look on a wall. The card’s white border can make colours appear different. Printed colours aren’t always accurate.
Cost: Usually free or very cheap.
Tester Pots
Best for: Seeing the actual paint on your actual wall. Testing in your specific lighting. Making a final decision.
Limitations: Cost adds up if you’re testing many colours. Requires painting directly on your wall (or using a sample board).
Cost: Around £2-4 for high street brands, £5-8 for premium brands like Farrow & Ball.
My recommendation: Use swatch cards to narrow down to 2-3 options, then buy tester pots for your final shortlist. Don’t skip the tester pot stage — it’s worth the few extra pounds to avoid repainting an entire room.
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How to Test Paint on Your Wall: Step by Step
Step 1: Paint a Large Enough Area
A tiny dab won’t tell you anything. Paint at least an A4-sized patch — ideally A3 or bigger. The larger the test area, the more accurate your impression will be. Small patches are too easily influenced by the surrounding wall colour.
Step 2: Apply Two Coats
One coat doesn’t show true colour. Most paints need two coats for full coverage and accurate colour. Let the first coat dry completely before applying the second.
Step 3: Test in Multiple Spots
Don’t just paint one patch. Test in at least two locations: one near the window (where light is strongest) and one further from the window (where light is weaker). This shows you how the colour behaves across the room.
Step 4: Let It Dry Completely
Wet paint always looks different to dry paint — usually darker and more saturated. Wait at least 24 hours before judging. Some paints continue to change slightly over 48-72 hours as they fully cure.
Step 5: Look at It Throughout the Day
This is the most important step. Check your test patch in morning light, afternoon light, and evening light (with lamps on). Paint looks dramatically different at different times of day. A colour that looks perfect at noon might look grey and flat by evening.
Step 6: Live With It for a Few Days
If possible, don’t rush your decision. Live with the test patches for 2-3 days. You’ll notice things you missed at first glance — undertones that bother you, or a colour that grows on you.
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Where to Paint Your Test Patches
Location matters. Here’s where to place your test patches for the most accurate results:
Near the window: Shows how the colour looks in the strongest natural light.
Opposite the window: Shows how the colour looks in indirect light and shadow.
Next to fixed elements: Test near anything that’s staying — your sofa, kitchen cabinets, flooring — to check they work together.
Avoid corners: Corners receive less light and can make colours look darker than they really are.
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The Sample Board Method (If You Don’t Want to Paint Your Wall)
Don’t want to paint directly on your wall? Sample boards are another great way to test paint colours without commitment.
What to use: Large pieces of white card, foam board, or lining paper. Avoid small pieces — bigger is better.
Once it’s dry, you can move it around the room to see how the colour looks in different spots. Tape it to different walls. Lean it against furniture. Live with it.
This is my favourite method because you can test multiple colours at once without your walls looking like a patchwork quilt.
How to do it: Paint two coats on your board. Let it dry. Then move the board around the room to see how the colour looks in different spots and at different times of day.
Pro tip: Tape the board directly to the wall rather than leaning it. This removes shadows and gives a more accurate impression of how the colour will look painted on.
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What to Look for When Testing Paint
When you’re looking at your test patches, ask yourself these questions:
Does it have unexpected undertones? Look carefully — is it pulling pink? Purple? Green? Grey? Undertones that aren’t obvious on a small swatch become very obvious on a wall. This is especially true in rooms with limited light, like small bathrooms with no windows.
How does it change throughout the day? Is it warm in the morning but cold by evening? Does it look grey when it’s cloudy outside?
Does it work with your existing elements? Check it against your flooring, furniture, curtains, and any other fixed features.
Is it too light or too dark? Paint often looks lighter on the wall than on the swatch. If you’re unsure, go one shade darker than you think.
Do you still love it after a few days? First impressions can be misleading. Some colours grow on you; others become annoying quickly.
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How Many Paint Samples Should You Test?
I recommend testing 2-3 colours maximum at the final stage. More than that becomes confusing and overwhelming.
If you’re stuck between lots of options, use swatch cards to narrow down to your top 3, then invest in tester pots for those finalists only.
Testing too many colours at once can lead to decision paralysis. Trust your instincts, narrow it down, then test properly.
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Common Paint Testing Mistakes to Avoid
- Testing too small an area. A tiny patch doesn’t give you the full picture. Go bigger.
- Only applying one coat. One coat doesn’t show true colour or coverage.
- Judging when wet. Always wait for paint to fully dry — at least 24 hours.
- Only looking at one time of day. Morning light, afternoon light, and evening light all affect colour differently.
- Testing in a corner. Corners are darker — test on a flat wall section.
- Rushing the decision. Live with your test patches for a few days before committing.
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My Top Tips for Testing Paint
Test at least 2-3 colours side by side. Comparison makes differences obvious.
Label your test patches. Write the colour name next to each patch with pencil so you don’t forget which is which.
Take photos. Photograph your test patches at different times of day. This helps you compare and remember how they looked.
Check the paint finish. Matt, eggshell, and satin finishes can make the same colour look different. Make sure your tester is the same finish you plan to use.
Trust your gut. If something feels off, it probably is. Don’t try to convince yourself to love a colour.
Quick Recap
Testing paint properly takes a little extra time and a few extra pounds — but it’s nothing compared to the cost and hassle of repainting an entire room because you chose the wrong colour.
Take your time. Test in your actual space. Look at it in different lights. Live with it for a few days. Then commit with confidence.
Your walls will thank you.
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Need Help Choosing a Colour?
I test paint colours in real UK light so you can see exactly how they look before you buy. Check out my other guides: