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Backscatter removal in Photoshop Tip


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#1 markprior

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Posted 01 April 2002 - 01:27 PM

One of the most annoying things about underwater photography is when a great picture is ruined by backscatter. This can lead to an age in Photoshop trying to use the clone brush to remove each particle individually.

The dust and scratches tool at first glance looks like an ideal solution for removing white particles on a background (backscatter). However this has the effect of softening the whole picture.

However there is a method of using this filter to radically speed up the backscatter removal process.

The first step is to apply the dust and scratches filter to your picture. Apply it strongly and do not worry about the softening effect on the foreground. Make sure that all of the particles are removed by the filter.

In the History palette revert back to the original picture directly before the application of the filter. Switch to the history brush and ensure that the source for the history brush is set as the state after the dust and scratches filter (The history must be set to non-linear in the history options). Set the mode for the history brush to darken.

Now using a suitable brush paint over the backscatter. The light particles will disappear leaving the dark information intact.

This should be a far quicker process than using the clone brush and should also maintain the grain of the picture and the detail around the backscatter.

This technique should work in any image editor that has a history brush

If the above isn't clear please post any questions.

Mark
Sea & Sea D200 Housing - 60mm,105mm, 10.5mm, 12-24mm (All Nikon) Sigma 17-70mm and Tokina 10-17mm lenses and a bunch of Ports.
Lighting: 2 x Ikelite DS-125, 2 x Manual controller

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#2 adobedavid

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Posted 20 May 2002 - 01:50 PM

Also I'd try using the new healing brush in Photoshop 7! It is nothing short of miraculous for eliminating backscatter! :)

#3 bobjarman

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Posted 22 May 2002 - 05:06 AM

Another great thing about the healing tool is that you can change it to a healing patch.

Try this, on a great macro/close up shot, often times you get a spot or two of coral that get blown out. You can switch to the healing patch tool, lasso the blown out fragment of coral, and then drag it to a section of the coral that looks similar but is not blown. Once you release and click on it, the bad section you lassoed, will be transformed to a good section. Really quite amazing, and in most cases, you cannot see any evidence.

I did this recently to a few images and was amazed at how well it fixed it.

#4 snoack

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Posted 29 May 2002 - 07:39 AM

Seems that it's about time to upgrade to Photoshop 7 then (instead of buying the macro lense ... ?)

Sabine

#5 Arnon_Ayal

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Posted 29 May 2002 - 11:11 PM

I use the Photoshop Element ( great software btw)
I can't find how to use the 'history brush', Does someone know it ?
Arnon Ayal www.arnonayal.com
Nikon D200, Ikelite housing, Dual SB105.

#6 Arnon_Ayal

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Posted 21 July 2002 - 11:00 PM

And to anyone else that use the PS Elements.
The History brush tool donít exist in the Elements :)
But I tried that tip in PS 6 and its worked fine.
Arnon Ayal www.arnonayal.com
Nikon D200, Ikelite housing, Dual SB105.