Levels in Photoshop

To present the use of levels in Photoshop I have chosen one of my old photographs and improved its colors and contrast. I have opened the picture in Photoshop, duplicated it by choosing Image --> Duplicate and added a Levels adjustment layer. In there I have moved the pointer on the left side of the histogram (dark areas) to 26 and the pointer on the right side (bright areas) to 216. I have also moved the middle pointer to 0.92 and set the white balance using the white color eyedropper. The original photograph had a greenish tint and I got more exact colors by choosing a white point with the eyedropper. Another thing I have done in order to improve the look of the picture was to use a Selective Color adjustment layer. I have changed settings for cyan and blue areas of the photograph to boost color of the sky. As the picture has still had a little bit of the green tint I have applied a violet filter using the Photo Filter adjustment layer. I have set the density of the filter to 38% and opacity of the layer to 59% to get the best result.