Saturday, August 8, 2009

Remove dust spots with Adobe After Effects

It's been a while since I wrote a tutorial how to remove dust spots with Photoshop, see here: http://magictimelapse.blogspot.com/2009/02/batch-remove-sensor-dust-in-images-with.html . Now if you have After Effects (I use AE CS4), you can skip this photoshop step and do it directly in After Effects.
Shooting on Sahara's dunes in Morocco's desert, I caught a large amount of sand grains in my camera (without actually changing the lense at any time, the sand just came in...), so I had to find an efficient way to remove the resulting dust spots...
Being an Adobe product, After Effects comes with a few filters that are also included in Photoshop, luckily also with the Dust & Scratches filter. As in Photoshop, you do not want to apply the filter to the whole frame, but only where the dust spots are. To do so, in AE one uses Masks:
First import your images into a new composition. Copy your ground layer by clicking on it and pressing ctrl-c ctrl-v:

You have now two layers. Select the upper layer. Then click on the "Ellipse Tool" in the tool bar (if the ellipse tool is not there, just alt-click onto the corresponding symbol until it appears):

using this tool, mark all dust spots in your image:


In the upper layer, two mask have appeared:

By clicking on the little arrow, you can open their menues. Change the values of "Mask Feathers" to maybe 5 - 10 Pixels. This value says (at least if I understood correctly...) how sharp the mask will be:


The open the Effects menu, select the Noise & Grain menu and there the Dust & Scratches filter. Drag it onto the upper layer:

Set the "Radius" value of the filter to maybe 20-40 and the threshold to 0. The dust is gone and it will not look washed out as if you use the stamp tool to do the same!


Btw: If the spots are still a little dark, it helps to increase the brightness of the upper layer a few percentages (Filter... Color Correction... Brightness & Contrast)




I will upload the finished timelapse movie somewhen next week onto vimeo and youtube!



Find my timelapse movies here:
www.magictimelapse.ch