How To Change Bit Per Channel In Photoshop

Reducing Noise In Images With Photoshop

In this Photo Retouch tutorial, nosotros'll look at how to reduce the appearance of noise in an image, including luminance noise, color racket and even jpeg artifacts, all using the Reduce Noise filter, get-go introduced in Photoshop CS2 (which means you'll need at least CS2 to follow forth).

Detect that the name of the filter is Reduce Noise, not Remove Noise. Every bit powerful equally Photoshop is, in that location's even so no way to take a noisy image and clean it upwardly completely, at to the lowest degree not without removing most of the detail in the image forth with it.

Any time nosotros shoot in low calorie-free, use high ISO settings, or leave the expensive dSLR at home considering the compact photographic camera is easier to deport, there's a good chance nosotros'll be dealing with noise. Fortunately, while nosotros can't remove information technology completely, Photoshop's Reduce Dissonance filter nonetheless does a good job of reducing noise without sacrificing important paradigm particular. Let's run across how it works.

Hither's an image I have open on my screen, taken a couple of years agone while walking through Brute Kingdom in Disney World. I haven't done anything with the image yet other than cropped it a niggling:

She may look bored, but you wouldn't like her when she'due south angry.

As I mentioned, there'south iii types of noise that the Reduce Noise filter can tackle. One of them is colour noise, usually made up of reddish, green and blue dots. This image was taken with an inexpensive point-and-shoot camera, a prime candidate for noise, and if I zoom in on the gorilla, nosotros run across lots of red, green and blue "splotches" in her fur, specially along the edges between the dark shadow areas and the lighter areas:

Red, green and blue color noise is visible when we zoom in.

Let's come across what the Reduce Noise filter tin can exercise for us. To open up the Reduce Noise filter, go up to the Filter menu, cull Racket, and and so cull Reduce Noise:

Go to Filter > Noise > Reduce Dissonance.

The Dialog Box

The Reduce Dissonance dialog box contains a large preview surface area on the left so nosotros can run into what nosotros're doing (although nosotros can also see what we're doing in the document window itself every bit long as the Preview option is checked, which it is by default) and some sliders and options along the right. Even though it'southward non so obvious, the column forth the correct is actually divided up into different sections, with each section affecting a different blazon of noise. I've colorized the sections nosotros're most interested in.

From acme to bottom, the beginning ii sliders, Force and Preserve Details (colored in green), are used to remove luminance noise, which we'll look at shortly. Next is the Reduce Color Noise slider (yellow), which, as you may take guessed, reduces colour dissonance. Beneath that is a slider we're not going to look at, Sharpen Details (non colored), since it has nothing to exercise with reducing noise. Sharpening images, which is what this slider does, is better handled with one of Photoshop's bodily sharpening filters, like Unsharp Mask or Smart Acuminate, so I'd recommend lowering the Acuminate Details option downwardly to 0%, effectively turning information technology off. Finally, we have the Remove JPEG Artifact option (blueish) for reducing the appearance of jpeg compression artifacts:

The Reduce Noise filter dialog box. Different sliders and options reduce different types of noise.

To get the most out of the Reduce Noise filter, information technology's all-time to brainstorm by turning the filter off then information technology has no effect on the image. In that location's no bodily "Off" push, but we can attain the same thing by dragging all of the sliders to the far left, which sets each option to 0. Also, brand sure the Remove JPEG Artifact selection is unchecked.

Navigating The Preview Area
To zoom in and out of the image within the preview area, click on the Plus ( + ) and Minus ( - ) icons forth the bottom. The current zoom level appears between them. Click and drag within the preview area to move the image around equally needed:

Use the + and - icons to zoom in and out of the image. Click and drag to move the epitome effectually within the preview area.

Color Racket

The offset type of noise y'all'll want to check for and reduce is color dissonance, those ruddy, dark-green and blue dots like the ones we're seeing in my prototype. Utilise the preview window in the dialog box to zoom in on an expanse that contains color noise. Start with the Reduce Color Noise option set to 0%, then slowly drag the slider towards the right until the colour racket has blended in with the image as much as possible. Continue an eye on the preview surface area every bit you lot elevate the slider to guess the results so you don't cease upwardly dragging too far:

Drag the Reduce Color Dissonance slider towards the right until the color noise disappears.

To apace become a "before and later" view of the paradigm so you can see how much of an improvement you lot've made, click and hold within the preview surface area. This shows you what the original version looked similar. Release your mouse push button to see the effects of the Reduce Noise filter.

In my example, the color noise seems to disappear nicely with a Reduce Color Racket value of around 60%. We can encounter in the preview window that the red, greenish and blue dots accept been removed. The value y'all finish upwards using will depend entirely on your image, and then it's of import to lookout man the preview area as you elevate the sliders:

Dragging a single slider towards the right was all it took to remove the color noise from the prototype.

Luminance Noise

One time yous've taken care of any color noise, information technology's time to reduce luminance racket. Unlike color dissonance which is fabricated upwardly of different colored dots, luminance noise contains dots of varying effulgence levels (black, white, and grayness). I'm going to switch to a different image, one where the luminance racket is easier to meet. Normally, of form, you'd all the same be working on the same epitome. Here's a photo shot in a dimly-lit museum at ISO 2000 with my Canon 5D Mark II:

Dissonance in an paradigm tin be difficult to see when you lot're zoomed out too far.

Fifty-fifty though the camera does an amazing chore of keeping noise to a minimum at such high ISO settings, if I zoom in on the epitome inside the Reduce Dissonance dialog box, we still see quite a lot of luminance noise:

All those black, white and gray speckles are luminance noise.

Removing luminance racket is a simple two-step process, just call back, we need to accept realistic expectations. In my case here, at that place'southward no way I'll be able to brand an epitome shot at ISO 2000 look just as clean and smooth as if I had shot it at ISO 100 or 200. All we can practise is try to make the image look amend than it did originally.

Starting time, start with the Strength value fix to 0%, then slowly drag the slider towards the right while keeping an eye on the image in the preview area until every bit much of the luminance racket as possible is removed. Click and hold inside the preview surface area to run across what the image looked like originally, then release your mouse push to see how much noise reduction has been applied. Once you've removed all the noise you tin can, brainstorm dragging the Preserve Details slider towards the right to bring back as much image item as possible without re-introducing the noise. It's a fine balancing act between removing noise and maintaining particular, and the values you finish upwards using for Strength and Preserve Details will exist dissimilar for every image:

Remove equally much noise equally possible with the Strength slider, then bring back detail with Preserve Details.

Avant-garde Options

If yous can't seem to reduce the noise without losing lots of image detail, endeavour the Advanced Options, which allow us to reduce noise on a aqueduct-past-channel basis. Kickoff, set the Strength slider dorsum to 0, then select Advanced in the top right of the dialog box. With Advanced selected, click on the Per Channel tab:

Select the Advanced option, then click on the Per Aqueduct tab.

Most images are fabricated upwardly of three color channels - Red, Light-green and Blueish - and it'southward very common for one of these channels to contain more noise than the others, with the Blue channel often existence the biggest offender. By reducing noise on a channel-by-channel footing, we tin utilise the strongest amount of noise reduction to the channel that needs information technology the most, leaving more image detail in the cleaner channels.

Cycle through the channels using the Aqueduct option direct below the smaller, blackness and white preview surface area. Click and elevate within the preview area to move the image around every bit you lot inspect the channel for dissonance. Beneath the Channel option are the same Force and Preserve Details sliders we saw before, only this time, they affect only the selected channel. But as we did a moment ago, start with both sliders prepare to 0, then brainstorm dragging the Strength slider towards the right to remove as much noise equally possible in the channel. Click and agree inside the blackness and white preview area to view how the channel looked originally, so release your mouse button to view information technology with the dissonance reduction applied. Once y'all've removed equally much noise as possible, brainstorm dragging the Preserve Details slider towards the correct to bring dorsum some image detail without bringing dorsum too much noise. Hither, I'one thousand reducing racket in the Blue channel, which in my case is the noisiest channel of the three:

Switch between the three color channels, then utilize unlike amounts of noise reduction to each aqueduct.

Once you've done all you lot can in each channel, switch back over to the main controls by clicking the Overall tab to the left of the Per Channel tab, so try once again with the main Forcefulness and Preserve Details sliders to run into if yous can fine-tune the results even more:

When you lot're done with the private channels, fine-tune things with the Overall sliders.

JPEG Artifacts

Finally, whenever y'all're working with jpeg images, whether yous're shooting jpegs with your digital camera or the image was saved as a jpeg in Photoshop or some other program, you lot'll see jpeg compression artifacts, which make the image look like information technology'due south been divided into a pattern of 8x8 pixel squares. Just how visible these artifacts will appear depends on how much compression was used, too equally how many times the paradigm was saved every bit a jpeg. Each time you re-save a jpeg image as a jpeg epitome, the quality becomes worse.

To reduce the appearance of the compression artifacts, select the Remove JPEG Antiquity pick:

Select the Remove JPEG Antiquity selection to reduce the appearance of jpeg pinch.

Make sure yous inspect the paradigm when this pick is selected, since it could result in a loss of too much detail. As with luminance and color noise, information technology'south ever a trade-off between reducing noise and keeping as much paradigm particular as possible. When yous're done, click OK in the superlative correct corner of the dialog box to apply all of the settings and go out out of the Reduce Noise filter.

And there we have it! Check out our Photo Retouching department for more Photoshop image editing tutorials!

Other Stuff

© 2022 Photoshop Essentials.com.
For inspiration, not duplication.
Site blueprint by Steve Patterson.
Photoshop is a trademark of Adobe Systems Inc.

Source: https://www.photoshopessentials.com/photo-editing/reduce-noise/

Posted by: northingtondarke1993.blogspot.com

Share this post