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Need help editing speckles... I think


drogemeister

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Hi! I'm new to the forum, but have been messing around with PS for years. Never really got into all the abilities of PS until now, as I'm taking photo editing serious. Right now, as I save up for a nice camera, I have a 16mp camera on my phone. It takes great pics where there is a lot of light, but when the lighting isn't great, I get speckles of red/gray. I've attached an example of the issue.

What is the best way to fix this, besides getting a new/better camera?
 

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  • 2015-10-15 10_57_07-20151014_110035_BEST.jpg @ 16.7% (RGB_8#) _.png
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hawkeye

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That's called noise and it's most apparent in high ISO photos. Use Filter-Noise-Reduce Noise to lessen the effect.
 

Tom Mann

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Hi! I'm new to the forum, but have been messing around with PS for years. Never really got into all the abilities of PS until now, as I'm taking photo editing serious. Right now, as I save up for a nice camera, I have a 16mp camera on my phone. It takes great pics where there is a lot of light, but when the lighting isn't great, I get speckles of red/gray. I've attached an example of the issue.

What is the best way to fix this, besides getting a new/better camera?
As I'm sure you know, by far, the best way is to reduce the noise at the source, not after the fact. The old saying, "closing the barn doors after the horses have left" is very appropriate in this case, LOL.

With any camera, whether it's a cell phone or conventional, if the subject isn't moving, if you make the shutter duration longer, this will allow you (or the camera, if it is automated) to use a lower ISO without any change whatsoever in the exposure. For example, if the image you posted was taken at 1/60th of a second at ISO 800, reducing the shutter speed to say 1/8th of a second (ie, three stops longer) would allow the ISO to be dropped by three stops to ISO 100, and the noise would be reduced dramatically, if not essentially gone. Of course, this only works for stationary subjects (like yours), and if you have a good steady hand or can brace the camera against something to avoid camera movement. For some cell phones, 3rd party apps are available which allow you to do exactly this. One example is an app called "645 Pro" for recent iPhones.

Another way to minimize the noise before it gets baked into the image is to simply add some more light to the scene. Often this is involves nothing more than turning on a few more lights in the room or opening the curtains.

One should turn to noise reduction software ONLY if you can't do either of the above because the results will never be as good. Here's a brief introduction to the subject: http://www.cambridgeincolour.com/tutorials/image-noise-2.htm . Notice that the technical name of the type of noise that you asked about is "chroma noise".

Over the course of decades, many apps and plugins have been developed to try to deal with image noise. Some of the algorithms can be two or more decades old. Unfortunately, Photoshop's "Filter-Noise-Reduce Noise" is in this category. It works, but it's not as good as say the noise reduction (aka, NR) feature built into ACR, whose algorithm was last updated only a couple of years ago. However, by far, the best NR software is that supplied by 3rd party vendors as either plugins or stand-alone software. Three of my current favorites are "Neat Image", Topaz's "DeNoise", and "DeNoise Project", a German offering. That being said, even the best of these should only be used by someone who has a well developed eye for such problems and can tweak the process as needed. Cost is another issue. So the bottom line is, if at all possible, minimize the noise (eg, by the techniques I outlined above) before hoping that software will fix the problem.

As an example, attached below is the result of using Topaz DeNoise (plus some manual tweaks like "Levels") on your image.

One final point, the fractional amount of noise reduction one can achieve in software increases as the square root of the number of pixels in the image, and it is almost always better to apply NR as the very first step in the processing of an image, not as the last step, as it was here. For this reason, the image you posted was not really suitable to demonstrate the full capabilities of NR software. It was tiny in size, had to be further cropped to get rid of the non-image areas, and it was a screen shot, not the actual image file, another point of potential loss of resolution and other image corruption. It would have been much better if you had simply posted the original file itself, not this screenshot.

Cheers,

Tom M
 

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