View Full Version : Dust Spots and their removal?


Robt
05-30-2004, 10:00 PM
A few weeks ago I went a few miles north of here to take flower pix. The Skagit Valley is one of the larger areas of bulb farming in the world [not the biggest, just significent]. In the spring, huge fields of Tulips or Daffodills ...

As I was standing in a wonderful field of purple Tulips, a farm hand drove by with his truck. Unfortunitly I was changing lenses. Needless to say but I will any way:shucks; dust on CCD big time.

Now that I kept shooting [I left my cleaning gear home-60 miles], my favorate of the day shows ALL the dust I captured.

I have spent a month trying search after search and trying the results I needed.

Does any one have a fast efficient method that works or is it; Heal, heal, heal.

The attached Pix is opened from raw, and nothing else unless you consider changing it from 17meg to 100k significant. email if you want the original

Robert Collins--help

When I did healing then USM, the healing marks came out as smears.

HELP me to learn. Please

Mig
05-31-2004, 12:15 AM
Robert,

I'm not clear on what you did with this picture in photoshop, but most of it comes down to strategy. The first thing you want to do is try and fix the histogram. The super-fast way to do that - if you don't know how to do it by hand - is open up Levels and click AUTO. There's a tutorial on this site that tells you how to do a levels correction.
The healing brush, or just about any other tool in photoshop that I can think of will only add to the problems in this picture.
USM is death here because this picture suffers from "jpeg block" already and any sharpening will only add to the problems. (The square in the sample attached is a magnification of the trees and sky. It's all blocky. No good.)
So, the simple answer that I'd recommend is to keep really, really simple. Do almost nothing. Fix the histogram with a levels correction. If you had a noise reduction filter that could smooth out the blockiness that would be nice, but I doubt you have that.
So keep it simple. A couple of global adjustments are about as far as this picture can go. Anything over that will further degrade it.

Hope this helps,
Mig

Gary Richardson
05-31-2004, 12:38 AM
Hi Mig, don't you think that perhaps the blockiness of the posted image is because it has been compressed from 17 M pix to 100 k pix as stated in the original post by Robt. The trouble is Robt, the dust problem you complain of does not really show on the 100 k image. Perhaps if you just selected a section that was badly affected and sent just that at a lower compression we could get a better idea.

Robt
05-31-2004, 06:33 AM
Gary you are right. Going from a raw file only opened to a jpeg at a quality level lower than a snakes belly doesn't show things well, Thx for the suggestion of the crop. Mig, I have only opened the raw image and converted to jpeg [and of course made it 8 bit by doing so]. I saw no reason in adding to my errors when asking for help.

I would simply replace the sky but can't figure how to and keep the fact that the mountians [some approx. 20 miles away] really do fade into the air and a new sky would look phoney unless I know better how to do it which I don't.

Thanks

Robert Collins

jeaniesa
05-31-2004, 09:43 AM
One thing to try on the sky (where I see most of the dust spots) is to loosely select the sky (i.e., you don't have to perfectly select along the sky and horizon). Then copy the sky to a new layer and change the blending mode to lighten. With the move tool selected, use the arrow keys to nudge the sky layer a few pixels to the left or right. You should see the dust spots "disappear".

HTH,
Jeanie

Robt
05-31-2004, 04:41 PM
Jeanie,

It worked. To think how hard I tried and your wonderfully simple method worked!

Thanks to everyone for your help. I'd post the final but I haven't yet figured how to get it less than 175K with a jpeg level of zero.

Robert Collins

jeaniesa
05-31-2004, 05:32 PM
Glad I could help - thanks to Katrin Eismann's book! :bigthmb:

Jeanie

Gary Richardson
06-01-2004, 12:03 AM
Robert, to get a file size under 100k, first take a copy of your image, resize it down to a width of 800 pix, then you'll find you don't have to compress it too much. The image will obviously not show the fine detail of the original, but will give us some idea of the final result.

Robt
06-01-2004, 09:12 AM
This effort is not quite where I want it but nearly. The sky stiil bothers me for some reason even though it is what I saw that day thanks to the help from you all. Perhaps its time to learn about building gradients etc.

Robert Collins

Robt
06-01-2004, 09:16 AM
OOPS, forgot to add image. "...got to be smarter than the tool"

Gary Richardson
06-01-2004, 12:26 PM
The picture looks great Robert, really deep colours. I thought you still had dust on it when I first saw it, then realised it was on my screen. A quick flick with a duster and bingo. Don't you just wish all your problems were so easy. Best of luck with your photoshop learning.

jeaniesa
06-02-2004, 08:27 AM
Robert, Nice job getting rid of the dust spots! If the sky bothers you because it looks too hazy, try this:

1. Create a new layer on top and merge to that layer (Shift-Alt-Ctl-E).
2. With the new layer active, go to the channels palette. Highlight the red channel and Ctl-A (to select all) then Ctl-C (to copy).
3. Highlight the composite channel again, then go to the layers palette. Ctl-V and the red channel should paste in as it's own layer on the top of the layers palette.
4. Change the blending mode of the red channel layer to luminosity. This will help the sky, but make the foreground look wierd. So use a layer mask and a soft brush to "erase" the bottom part of that layer.
5. Create another new layer on top and Shift-Alt-Ctl-E to merge everything onto it. Change the blending mode to overlay and the opacity to 65%. Again, use a layer mask to erase the bottom portion of the layer.
6. Almost there, just do a simple levels correction to make the image "pop" a bit more. If the remaining "haze" is too blue, you might want to do a curves or hue/saturation adjustment to fix that.

I've attached your image with the above changes so that you can see the difference.

HTH,
Jeanie

Xaran
06-02-2004, 08:37 AM
Jeanie,

Have you got those instructions correct - CTRL ALT ~ selects the highlights.

I think it is SHIFT CTRL E to merge the layers to the current layer.

Christine

jeaniesa
06-02-2004, 08:40 AM
Ack - you're right Christine!! (My fingers just do it - I don't think about it anymore. ;) ) Thanks for catching my mistake - will go edit my post.

Jeanie

byRo
06-02-2004, 01:03 PM
...to fix the sky.

1) Copy the layer (Ctl_J);

2) Right click on the new layer to open blending options (or double-click);

3) Set blend mode to multiply (or screen, as you like);

4) Set blend-if to Blue (there's little blue in the foreground, so we're going to be fixing the sky only);

5) Slide the little black triangles to the right (you'll see the effect moving up the photo) until you reach the hills;

6) Alt-Click on the triangles to separate them and take the right triangle up to 255;

7) Keep adjusting (playing with) the triangles, blend mode, opacity until it's the way you want.

........Blend-if CAN be fun! :wink:


Roland
(sorry, don't think I can post an image - I'm hiding behind a thick firewall)

VidKid
06-24-2004, 11:01 PM
My favorite technique to remove Dust & Scratches is to use the Blur Tool.

Set Mode to Lighten for dark dust/artifact type spots with Opacity @ 100%, then use the Clone or Healing Tool for the few bigger spots.

VidKid

clivet
09-17-2005, 01:33 AM
Hi Robt, sorry this is a long time in coming - try my software for dust removal on this image - I did and it cleaned the image up easily! The software was designed for this very purpose and type of image!

http://www.phototeknik.com/imageduster

See what you think and let me know?

Clive Talbutt
Phototeknik.com

Kraellin
09-17-2005, 09:17 PM
working only with the original image posted, i noticed a LOT of noise in the picture. by resizing down to a smaller image it corrects almost all of this. i suspect this was a result of 'digital zoom' on the camera, which is basically nothing more than zooming in with a similar algorithm as photoshop. by resizing you get rid of that.

the next thing i did was clone out the dust in the sky and a few in a few other places. it really wasnt that much.

i then masked the sky and ran both a light median filter and a low gausian blur to even out the artifacting..

i also ran a histogram adjust to balance up the colors and brightness.

nice pic, btw :)

Craig