The dots are the same color
Don't fool your eyes
The human optical system is remarkably adaptive. Your brain compensates colour toward a white balance. If there is a lot of blue in your field of view, your brain counterbalances this by adding the opposite colour. As a result, the dot in the purple area appears greyer than it actually is.
That dot could be your calibrated monitor. It is why skin tones look unhealthy in your renders, and why colours shift between sessions without explanation.
Whether you work with film, video, photography, or graphic design: only when you perceive colour accurately will you deliver your best work. A neutral grey working environment takes your work to the next level.
Why not
Mix it yourself?
You cannot simply have middle grey paint mixed at a DIY store. You may find a shade of neutral grey that comes close, but getting that exact colour onto the wall is another matter entirely. Mixing methods are not accurate enough, the margin of error of the mixing machine is too wide, and no allowance is made for variations in the base paint. Base paint is never completely white and can vary in colour from one production batch to the next, from one pallet to the next, or from one tin to another. DIY stores do not adjust their formulae to account for different types of base paint.
The base paint we use for Grey Paint is the whitest and most consistent available, and is therefore largely free from variation. Every batch is retested for accuracy.
Deviation from middle grey is measured in L*a*b*, where L* represents lightness, a* red to green, and b* yellow to blue. Grey Paint deviates by less than 1 point on every value. That difference is imperceptible to the human eye, and it outperforms the most well-known grey cards on the market, including Munsell N5 reference standards.