Patchy paint can result if paint has been applied unevenly.
Patchy paint can be down to a variation in surface absorption.
Walls might appear patchy if they have variation in texture.
Using paint that is not fully mixed can cause a patchy appearance.
How to avoid a patchy paint job?
Apply paint as evenly as possible
Try to maintain a wet edge.
When using a roller keep the open side towards the area just painted.
Try to complete one full surface at a time.
Paint in an even grid pattern from top to bottom.
Cut-in before painting the walls, then roller as close as possible to the edge.
Complete small areas before moving on.
Additional notes
Ensure your paint is thoroughly mixed before application. The heavier solids will, over time, sink to the bottom of the can. These will normally be the colourants. It is vital they are fully re-activated into the paint before use. Pouring you paint into a ‘Paint Kettle’ or ‘Paint Tray’ can often help with this. Mechanically stir if possible.
Be aware that a brush and a roller can give two textures that might catch the light differently.
