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  #1  
Old 05-25-2006, 10:44 PM
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Gina_D Gina_D is offline
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channels

I've attached a photo that I'd like to ask for some direction on and I'm sure there are plenty that can offer that here! I've used channels only in a very limited way so far and that would be in converting a scan of a photo to black and white using the channel mixer in PS to minimize the channels with the worst of the problems.

This one, however, I'm dealing with color and I know that when I look at the channels for this attached photo individually, a great deal of the problems seem to be located in the red channel (spots) and the blue channel (stain on the arm, blotches on the skin). The green channel seems the "cleanest". So how do I take this information and go from here to address these issues and get a good start on this photo before getting down to the details? Thanks in advance!

Gina
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File Type: jpg cindy_web.jpg (97.2 KB, 96 views)
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Old 05-25-2006, 11:19 PM
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Hi Gina,
Here is an example of an advanced use of channels to repair this image.
I opened the image and also created a duplicate of it with PS Image>Duplicate.
I converted the copy from RGB to LAB mode. You will see that the damage is in all channels.
So from here the first thing I did was apply a Gaussian Blur to both the A and B channels (a value of 9 in each). The L channel was in bad shape but I knew from examining the RGB image that the Green channel was much better than the other. So the next move was to replace the L channel in the LAB image with the Green channel of the RGB image. To do this I clicked on the L channel in the Palette to select it only then went Image>Apply Image. From the pull down menu select the RGB image , the Green Channel and set the blend mode to Normal. YourLAB image now looks somewhat cleaner than the original. Next I converted the LAB image back to RGB.
The next step was to apply a strong Levels shift. I set the Black point on the lady's top button and white point to the blown out area just above her head.
Next, PS Filter>Noise>Dust and Scratches set to a value of 3 eliminated a bunch of those nasty little spots. You can touch up the image from there.
Small thumbnail attached to this message and a larger version at the link below.
Regards, Murray


http://img123.imageshack.us/img123/4...adrevmm8zp.jpg
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File Type: jpg Channels Gina D Rev MM Thumbnail.jpg (90.4 KB, 75 views)
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  #3  
Old 05-25-2006, 11:24 PM
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Craig Walters Craig Walters is offline
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hi gina,

i think you may be getting overly complicated here by going to channels. then again, i dont have ps and i know they do things differently. nonetheless, all i did was channl mixer and contrast/brightness and that's it. mostly, it just needs some blue.

the rest you simply clean up with clone, heal, or those type tools.

now, there are some other things you could do to get some pop, but the simplicity is just channel mixer and clean up.

craig
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File Type: jpg cindy_web-1-k-1a.jpg (92.9 KB, 42 views)
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  #4  
Old 05-26-2006, 12:02 AM
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Thanks Murray for the step by step process. I've gone through it myself per your instructions - first I've tried stepping into LAB mode and your specific instructions kept things clear. The only thing I didn't do was the blurring as I tend to not like doing an overall blur on a photo, but rather use it selectively if absolutely necessary. I did see some improvement with your method and I can see from this point I'd need to just start with the more delicate cloning and healing.

Craig, you could be right about over-complicating. I've seen some great results here from people doing things with the channels and other color spaces and thought this would be as good a point as any to step out and start exploring since some of the damage does seem more evident in specific channels. Even so, I will likely end up back where I started with my trusty cloning tool!

Thanks to you both,
Gina
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Old 05-26-2006, 12:32 AM
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Craig Walters Craig Walters is offline
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gina,

that's fine

i do know that ps is far superior in channel handling and adjusting than psp. so, if you can do it in channels and that's your interest currently, go for it

craig
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Old 05-26-2006, 02:57 AM
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Gary Richardson Gary Richardson is offline
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Hi Gina,

Real quick way to do this. Select Red Channel, copy as an Alpha. Then run Polaroid D&S Filter set to remove light dust. Finally copy it, and paste it into your Red channel.

OK you can work direct on the Red Channel with Polaroid D&S, but I prefer to get it right in the Alpha first.

Did this on your pic, then a very rough Colour correction with levels. Total time taken about 5 mins (including writing this and posting the image). Obviously there's still work to do, but it gets you in the ballpark pretty fast.
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Old 05-26-2006, 07:38 AM
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Gina, FYI, the LAB color space is very different from the others All of the detail is in the L channel. That means you can apply heavy blurring to the color which is all in the A & B channels and you will not impact the detail of the image.
Regards, Murray
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  #8  
Old 05-26-2006, 09:23 AM
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Janet Petty Janet Petty is offline
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I wanted to see if I could do a quick, acceptable fix. Obviously, it still has some issues but for the 7 minutes it took, it is a vast improvement.

I too used LAB mode. I used it for the blurring of the color channels and for some sharpening of the luminosity channel. Then I converted it back to RGB and realized that the problem with the red was still a problem. The red channel was duplicated and a quick gaussian blur was applied. The copy was then pasted back into the original red channel. Lastly, curves was applied to the new red channel to fix the color cast.

Janet
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  #9  
Old 05-26-2006, 09:37 AM
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Hi all

For those that use Elements I believe you can somewhat follow Murray's procedure. I can separate the Luminance to a layer, which I did. Then using grants tools I copied the green channel to the luminance layer I had produced. Then I blurred the red and blue channels quite a bit. To finish I could reduce the luminance layer opacity somewhat to get the best balance.

It worked although not as good as Murray’s but it would save a lot of work in cleanup.

Butch
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  #10  
Old 05-26-2006, 12:10 PM
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Gary,
Thanks for the suggestion. I tried your method and it works fine on the part of the image I saved for the web at only 100k, however, in it's full version (scanned at a res of 600), the d&s filter keeps processing and processing, never to finish (at least so far). I guess I could try at 300dpi, I just have been doing all my work at 600 so far and resizing when done.

Murray,
Thanks for that bit of important info with regards to blurring. I wasn't aware of that!

Janet,
Your version looks great too. This seems to show what I suspected, that quite a bit can be cleaned up in short order before the more detailed work is done.

Thanks all!
Gina
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