This Lightroom slider is not hidden in the sense that there is some special secret to finding it, but it is in a place where you probably would not think to look for it. This great video tutorial will show you how to take advantage of it to make your photos pop quickly and easily.
Coming to you from Anthony Morganti, this excellent video tutorial will show you where to find a hidden midtones slider in Lightroom and how to use it. The reason this slider is not in the general toning panel is because it is actual designed for color grading, but it works just as well for adjusting the luminosity of the midtones. Morganti makes a great point: the general toning panel only contains sliders for targeting the sides of the histogram, not the center, and as such, if you have an image mostly composed of midtones to which you want to give a bit of a boost, you will need to use the curves tool, which will certainly work, but might not be as easy or efficient. As with all editing, though, there is no correct way to do things, only what you prefer and what gives you the results you want. Check out the video above for the full rundown from Morganti.
Thank you Alex! This was a helpful video.