How do I remove dust spots?

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JohnR

How do I remove dust spots?
« on: 9 Sep 2007, 12:52 am »
Photoshop wizards, I need your help. I have to remove some dust specks that I can't seem to get off my negatives. Here's one, should be easy to fix?


mpauly

Re: How do I remove dust spots?
« Reply #1 on: 9 Sep 2007, 01:25 am »
Since you've got a uniform background there, you can use the stamp tool to select an area just next to the dust spot, then stamp it over the dust spot.  Or use the marque tool to select a small area next to the spot then copy and paste it as a layer over the spot.  If you have a bunch of spots to cover, the first method works the best as it doesn't create new layers.


Vapor Audio

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Re: How do I remove dust spots?
« Reply #2 on: 9 Sep 2007, 01:59 am »
Clone stamp ... irridacator of all fuzzy evils

JohnR

Re: How do I remove dust spots?
« Reply #3 on: 9 Sep 2007, 03:27 am »
Cool, thanks guys, I'll give it a shot!

Vapor Audio

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Re: How do I remove dust spots?
« Reply #4 on: 9 Sep 2007, 04:31 am »
Oh geez, just noticed you said negatives ... clone stamp is a Photoshop thing obviously, so that only applies if you're scanning in the negatives   :duh:

JohnR

Re: How do I remove dust spots?
« Reply #5 on: 9 Sep 2007, 11:50 am »
Yep, scanning B&W. Works a treat :thumb:

drphoto

Re: How do I remove dust spots?
« Reply #6 on: 9 Sep 2007, 04:41 pm »
If you have a lot of dust, here's a neat trick that relies on the fact you can use the Snapshot feature of History to paint w/ filters.

Zoom in on your image and find the most common size spot. Go to Noise>Dust and Scratches and select the minimum pixel radius and maximum threshold radius that wipes out the dust spot but retains the texture (noise and/or grain structure) of the image. Don't worry right now the filter has probably obliterated the details of your image. (the D&S filter could also be called the 'edge destroyer') BTW the filter does a poor job w/ scratches despite it's name.

Now, and you must follow this sequence. Go to your History palette and click New Snapshot. Then immediately hit Undo (Cmnd+Z on a Mac
The image will now appear as before you did anything.

 Now choose the History Brush (Y). Set the source for the HB by clicking the EYEBALL next to the new Snapshot (NOT the snapshot itself)  Choose an appropriate brush size and hardness and just go and paint away that dust, making sure to steer clear of edge details. If you have areas w/ relatively little detail, this method can be very fast.

You can do the Snapshot/History Brush trick w/ any filter! Paint in selective blurs, sharpening, whatever.

Cool huh?

TONEPUB

Re: How do I remove dust spots?
« Reply #7 on: 9 Sep 2007, 04:50 pm »
Try the dust and scratches filter if you do not have an area with a lot of texture.
It will often eliminate detail, but if you have a big flat surface of even tone, you
can luck out sometimes with this one.

Forget the clone brush and use the healing tool, it will set you free!!

nathanm

Re: How do I remove dust spots?
« Reply #8 on: 10 Sep 2007, 03:25 pm »
You can either go with destructive or non-destructive edits.  A variation on the method described by drphoto would be to float a copy of your image on its own layer, Dust and Scratch filter it and then add a layer mask.  Then use the paintbrush on the mask to touch up the dusty bits.  This has the advantage of not having to use the mouse to click back and forth on your History Brush clone source, if you screw up you just repaint with the inverse color. (white or black-X key swaps)  This is handy when there's dust mixed in with desired image detail.  If you mainly notice dust's miraculous property of only adhering to the sky parts of your image you can simply go into Quick Mask, paint over the sky quickly and then Dust & Scratch filter that.

The healing tool is cool, but you really have to be careful not to touch higher-contrast pixels or you get that awful spotlight effect. 

JohnR

Re: How do I remove dust spots?
« Reply #9 on: 11 Sep 2007, 09:01 am »
A variation on the method described by drphoto would be to float a copy of your image on its own layer, Dust and Scratch filter it and then add a layer mask.  Then use the paintbrush on the mask to touch up the dusty bits.  This has the advantage of not having to use the mouse to click back and forth on your History Brush clone source, if you screw up you just repaint with the inverse color. (white or black-X key swaps)

OK, this makes about as much sense to me as "sdfj l i njhsldkfjh ksjdfkj lsdf" :lol:

I will remember this thread and come back to it once I get a little further with this though :)

nathanm

Re: How do I remove dust spots?
« Reply #10 on: 11 Sep 2007, 03:57 pm »
Yeah I know...I'm a lousy teacher!  :oops:  But "34fjdsahffd sdaf dsf fdsa" is about how I feel about darkroom work now, so I guess it goes either way. 

Start playing with the stamp\clone tool, you'll pick it up in no time.  The only time it gets tricky is when the dust is mixed in with bits of image that have detail.  That's when you have to do the more involved layer stuff.  Zoom in close and try to use as small of a brush as you can get away with. 

I just recently discovered an actual use for the Dissolve blending mode; cloning out dust in areas where there's a lot of grain.  Cool! 

With Photoshop there's always at least three or four different ways to do the same thing so it might seem more complicated than it actually is.