When retouching your images, are you using a check layer to see what might not be seen in the shadows and the highlight areas of the photo? If not, you may be overlooking some areas that need work.
In this video, automotive photographer Andrew Link shares how he uses a check layer or helper layer in his work. In one of his speed edit videos, a few people questioned the purpose of a layer he adds that gives his image a weird effect. This "cheater layer" as Link calls it, is an "M" curved layer which he uses to help see into the dark shadows or the highlights of the image to see what needs to be corrected. Throughout the video, he shares what it was used on in a few different images and what are some of the areas that needed to be corrected. This helper layer can be useful when blending multiple exposures together, especially when you have different shadows in multiple images as Link shows in his last example.
When I retouch portraits, I use a few helper adjustment layers to aid in seeing what areas of the skin need to be retouched, but I don't often use one to check the shadows and highlights. What other types of helper layers do you use in your work?