In this step, we'll use a similar 'S' shaped curve as before, but this time using the RGB setting in the drop down menu. The RGB setting offers more flexibility as it allows you to adjust individual color channels by ticking and unticking the Red, Green and Blue tick boxes. However we're going leave them all selected and adjust all three color channels equally.
Change the drop down to RGB and curve the line into an 'S' shape as in the last step. This time you'll see that not only has the image gained more contrast, but the colors also appear more saturated and vibrant.
This gives you two simple options for making adjustments to your photos in Paint.NET using Curves.