Soft proofing gives you the ability to see what your image will look like when uploaded and viewed on a monitor or when printed. You can input the type of printer and paper and Lightroom will simulate the outcome so that you can tweak it by lowering the saturation of out of gamut colors or increase the contrast for a better printed image. You can turn this on quickly in the develop module by hitting your “S” key. The left icon in the histogram panel is to see where your monitor can’t produce color correctly. Hover over this icon to see where your monitor may have trouble and then make the corrections. The right icon is for paper. Select the type of paper you want to use and you will see out of gamut warnings showing up in RED. Lower your saturation until the warnings are gone. You can also make contrast adjustments as needed.