I want to discuss how lighting affects how you see hair color. The picture at the top of the blog today is of the same dollhead, only taken under different lighting conditions. In fact, these pictures were only taken about a minute apart. The cooler look on the right is thanks to the addition of a cool toned ring light to adjust the temperature of the picture. And even that isn't a true representation of what I see when I look at the color. My interpretation of the color is a bit cooler and more grey looking. One of the hardest things to show in pictures is what it looks like in person.
With this demonstration, you can see how lighting affects what you may interpret when you see a color. While you are in the chair, the lighting is going to, generally, appear warmer than under a ring light or outside. Color almost always appears a bit cooler outside due to the blue light that is reflected in the environment. Once you get indoors under incandescent lighting it will look much warmer. Every lighting scenario will change how hair color appears. This is shown by the example of picture above. And, if there has been some editing, the in vivo color might not look like the picture at all.
This becomes very important when looking at the results after a color service. If it looks too warm or cool, that could very well be the lighting. Not to mention how you, personally, see color. I know that my left eye sees more red than my right, so many colors most likely appear a little more rosy to me than someone else. It is difficult to try and understand that no one sees color exactly the same as you do.
In conclusion, don't take what you see in pictures as a factual representation of what a color looks like. And accept that the color will shift in all kinds of lighting.