Reef Sanctuary - View Single Post - Photoshop seminar 3- selective sharpening

Travis · 01-23-2004, 01:14 AM

Note: My apologies to you dial-up users. This is an image-intensive lesson, and I had to use large files to illustrate the noise we're dealing with.

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If you have downloaded my actions, you know the great benefits of the "high-pass" filter. However, there can be a major drawback to sharpening. That drawback is added "noise." This can be a real problem if you're cropping or displaying larger pics. How bad depends on your sensor and varies with the color and sharpness of the area of the photo. If you've ever seen a pic with a "grainy" look, that's noise.

The noise will be worst in areas that are out of focus. The areas in focus generally handle sharpening the best, while parts not in focus (especially the background) will show tons of noise when sharpened.

In this little class, I'll teach you how to "paint" the sharpening (or any other effect) on to only the part of the photo where you want it, namely your subject (if that's not in focus, you need to get rid of the pic- sharpening won't help you there).

Now, there are two ways to do this that I know of. I'll go over the first and easiest method here.

OK, here's our sample pic before sharpening:

Here's a cut of the background at 100%:

Here's the sample pic after sharpening:

And a cut of the background, post-sharpening, at 100%:

At this point, you will have run your high-pass filter and if you blow up the background to 100% should notice the added noise. If not, go to your "Layers" palette and click the eyeball next to the top layer on and off- this shows/hides the high-pass filter. As you clik on and off, you will be able to see the difference. Now, here's how to fix it.

Go to layer--> add layer mask-->hide all

The sharpening effect wil disappear. Don't worry, it's not gone. You're just going to "paint it on" to only the places where you want it. In your main toolbar, make sure your fore/background colors are black and white by clicking on this:

Now, click on the brush tool on the same toolbar. Then, carefully drag the brush around the edges of your subject. You want to get all the edges, but you want to avoid painting over background where possible. Don;t try to be too perfect your first few tries, just try to keep it inside the fish.

Now, to see your progress, in the layers palette click the eyeball icon next to your "background layer" so the eyeball is off. You now see what you have painted on in the high-pass layer. It should look like this:

Now, paint the inside of the fish using the boundaries you have created. When done, click the background layer back on. Voila! Your fish (or other subject) is sharpened, but nothing else is. (Since the algae in this shot was in focus, I sharpened it as well.)

Here's your finished product:

And here's that 100% blowup showing no additional noise in the background, but you can see where the fish has been sharpened:

Now, just flatten your image and you're done!

01-23-2004, 01:14 AM	#1 (permalink)
Travis Smilie Bartender Join Date: Nov 2003 Location: Dallas, TX Posts: 6,657 View Gallery Karma Komment Add yours!	Photoshop seminar 3- selective sharpening Note: My apologies to you dial-up users. This is an image-intensive lesson, and I had to use large files to illustrate the noise we're dealing with. ----------------------------------------------------------------------------------- If you have downloaded my actions, you know the great benefits of the "high-pass" filter. However, there can be a major drawback to sharpening. That drawback is added "noise." This can be a real problem if you're cropping or displaying larger pics. How bad depends on your sensor and varies with the color and sharpness of the area of the photo. If you've ever seen a pic with a "grainy" look, that's noise. The noise will be worst in areas that are out of focus. The areas in focus generally handle sharpening the best, while parts not in focus (especially the background) will show tons of noise when sharpened. In this little class, I'll teach you how to "paint" the sharpening (or any other effect) on to only the part of the photo where you want it, namely your subject (if that's not in focus, you need to get rid of the pic- sharpening won't help you there). Now, there are two ways to do this that I know of. I'll go over the first and easiest method here. OK, here's our sample pic before sharpening: Here's a cut of the background at 100%: Here's the sample pic after sharpening: And a cut of the background, post-sharpening, at 100%: At this point, you will have run your high-pass filter and if you blow up the background to 100% should notice the added noise. If not, go to your "Layers" palette and click the eyeball next to the top layer on and off- this shows/hides the high-pass filter. As you clik on and off, you will be able to see the difference. Now, here's how to fix it. Go to layer--> add layer mask-->hide all The sharpening effect wil disappear. Don't worry, it's not gone. You're just going to "paint it on" to only the places where you want it. In your main toolbar, make sure your fore/background colors are black and white by clicking on this: Now, click on the brush tool on the same toolbar. Then, carefully drag the brush around the edges of your subject. You want to get all the edges, but you want to avoid painting over background where possible. Don;t try to be too perfect your first few tries, just try to keep it inside the fish. Now, to see your progress, in the layers palette click the eyeball icon next to your "background layer" so the eyeball is off. You now see what you have painted on in the high-pass layer. It should look like this: Now, paint the inside of the fish using the boundaries you have created. When done, click the background layer back on. Voila! Your fish (or other subject) is sharpened, but nothing else is. (Since the algae in this shot was in focus, I sharpened it as well.) Here's your finished product: And here's that 100% blowup showing no additional noise in the background, but you can see where the fish has been sharpened: Now, just flatten your image and you're done!