For this tutorial we will be removing the background from a figure and then replacing this with an aura around the figure which will have a texture. First take your original footage, and draw a mask around it with the pen tool. You will have to activate the timer for the "Mask Shape", at the beginning of your footage. Next use the Page-up and Page-down keys on your keyboard to move forward and backward a keyframe at a time. At each keyframe interval you will have to adjust your mask shape, unless of course your figure has minimal movement. In this case, I used a dancer which had excessive movement at times. I would also like to note that reducing your framerate from 30fps to 15fps, theorectically reduces your worktime by half.

This mask will be used several times throughout this tutorial. Next I created a "White Solid" and an "Adjustment Layer". You can see in the above image which effects I used in the "Adjustment Layer", you will choose your own. Next copy the "Mask Shape" keyframes and paste them into the "Adjustment Layer" and the "White Solid". Both of these combine to cover the bulk of the space and finer details. It's up to you how close you wish to get to the figure in the original creation of the mask. In the "Adjustment Layer" you can play with the "Mask Expansion" a bit, to get closer to the image.