Does anyone know if the Blue colour of 15500 15400 15510 is the same?
I read that 15510 is more navy? Overall how do they compare?
The shade of blue is not uniform among the three. Even looking at official AP renders suggests that each of the dials aren't "meant" to be exactly the same shade. It may not even be uniform among within iteration either, with some batches having a certain hue that others do not (think of the 15202's earlier serials vs. newer serials, and then later the 16202).
I have heard that the way in which they produce these blue dials has changed over time, switching from galvanization to PVD to create more consistency and reduce rejection rate. This too may affect perception. Whether that is completely true or not I do not know, we would need confirmation from a more reliable source.
At the end of the day, unless you have them in the exact same place under the same or very similar lighting conditions it isn't going to be easy to fairly judge the nuanced differences between the three (or more, depending on individual example) blue shades. Pictures online will only take you so far, as will other people's first-hand experiences that will invariably differ from your own, even in the same circumstance.
