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How to reduce noise

“Smooth, CK, real smooth…”

Introduction

I’ve recently discovered the Topaz Labs suite of software products that includes Sharpen AI, Gigapixel AI and DeNoise AI. This article discusses how best to use the last of these.

DeNoise AI allows you to reduce noise in your images better than any other product on the market, including Lightroom or Photoshop, and it also has a variety of other features similar to those in Sharpen AI:

  • regular software updates to improve performance

  • three different algorithms to choose from (DeNoise AI, All Clear and Low Light)

  • option to choose algorithm automatically (except in Comparison View)

  • masking (either manual or automatic using the Find Objects button)

  • Recover Original Details slider

  • Color Noise Reduction slider

  • automatic settings for Remove Noise and Enhance Sharpness

  • automatic selection of noise reduction mode (except in Comparison View)

  • Brighten button (to improve visibility on dark images without affecting the saved brightness)

  • zoom (presets and manual entry)

  • batch processing for multiple images

  • Undo and Redo buttons

  • Preview window

  • Original button to toggle between the sharpened and unsharpened image (in Single View)

  • tool tips where there is a ‘?’ icon

  • four different view options:

    • Single View

    • Split View

    • Side-by-side View

    • Comparison View

Getting started

The first thing you’ll have to do, obviously, is download the software. Topaz Labs has a suite of three main programs: Sharpen AI, DeNoise AI and Gigapixel AI.

You can buy them individually or as a set, but it’s probably worth taking advantage of the free trial first of all.

Both Sharpen AI and DeNoise AI offer sharpening and noise reduction, but, as the names suggest, they each have a different specialism. Gigapixel AI is used for increasing the file size of your images, and that’s handy if you’ve cropped in heavily and/or you don’t have enough pixels to play with.

As it happens, I’m an affiliate for Topaz Labs, so you can get 15% off any purchase by following this link and using the discount code nickdale15.

Once you’ve downloaded, installed and opened up the software, you’re ready to go.

You can either drag images directly into the main window or click the Browse button to find the image(s) you want.

DeNoise AI window

Alternatively, you can right-click on any image in Lightroom, select Edit In and pick Topaz Labs DeNoise AI from the list. (The program is automatically added to this menu option when you install it.)

Edit in Topaz Labs DeNoise AI from Lightroom

Edit in Topaz Labs DeNoise AI - options

Workflow

DeNoise AI has a simple interface, and it’s very easy to use.

What I tend to do is use as many of the automatic settings as possible and only play around with the manual sliders if I’m really not happy with the results.

Here’s my workflow.

  1. Drag the first image into the main window (or on to the icon in the Dock if the program’s not already open).

  2. Click on View in the top menu bar and select Comparison View (to show the original and three of the four available noise reduction options).

  3. Click on Zoom in the top menu bar and select Zoom 100% (or simply hit Command+2 on the Mac or Control+2 on the PC).

  4. Click on each of the Standard, Clear and Low Light windows (or the buttons in the right menu bar) and toggle the Settings to Auto.

  5. Make sure the Recover Original Detail and Color Noise Reduction sliders are set to zero.

  6. Click on the eye of the subject in the preview window.

At this point, you can simply look at the three different windows to see which option has done the best job at reducing noise in your image.

If you want to go to Single View to widen your work area, just double-click on one of the windows.

If you want to try the Severe Noise AI Model (new in version 3.1), then just select any window and click on the Severe Noise button in the right-hand menu. To go back to the previous window, just click on the appropriate button.

This works for any of the AI Models: just click on the button for the one not shown, and it will automatically replace the active window.

(Just be aware that the new AI Model won’t replace the current window if it’s already showing among the three visible windows.)

I find that the Low Light option is best at reducing noise in the background - even when light levels aren’t particularly low - but it’s worth comparing all three to the original.

(Topaz Labs recently updated the Low Light algorithm, but it ended up being so bad that Anthony Morganti panned it in his review, so they went back to the old version! Phew…)

Once you’re happy with the version in one of the windows, you can export it in any of a number of different formats:

  1. Click on the relevant window or button to make sure it’s selected (as shown by the blue rectangle in the corner)

  2. Click on the Save Image button (or the Apply button if you’ve opened DeNoise AI from Lightroom.

  3. Choose the appropriate options:

    • Image Format (Preserve source format, JPG, JPEG, TIF, TIFF, PNG or DNG)

    • Filename

    • Save directory (Source or Custom)

  4. Click Save

Save Image As

Options

Manual sliders

If the image is not sharp enough or too noisy, then you have a few different options:

  • Play with the Remove Noise and Enhance Sharpness sliders

  • Play with the Recover Original Detail slider. This will help to bring back detail into your image, but the trick is to find that ‘sweet spot’ when it doesn’t come at the expense of too much noise.

  • Play with the Color Noise Reduction sliders. Colour noise reduction in Lightroom is actually very good, and you only need to move the slider to around 10-25 in order to remove it completely. However, it’s just not necessary to do that as DeNoise AI’s noise reduction generally doesn’t leave anything for the Color Noise Reduction slider to do.

DeNoise AI doesn’t always produce the perfect result, so you’ll sometimes have to make manual adjustments.

On a few occasions, DeNoise AI just won’t be able to rescue the image, so all you can do then is delete it and load the next one on your list.

View modes

I find the Comparison View the quickest and most useful way of working out which method of sharpening to use, but it depends on the image.

I guess it’s also a matter of taste.

It is quite cool when using Single View to press and hold the Original button to see the difference between the ‘noisy’ and ‘denoised’ images. In Split View, you can drag the central line across the image to divide it in two, with one section showing the original image and the other showing the denoised version.

Performance

DeNoise AI and particularly Sharpen AI used to take a long, long time to save files. It’s a lot better in the latest release (v3.0.3), but you can speed things up by making a couple of changes in Preferences (Command + , on the Mac or under Topaz DeNoise AI in the main menu):

  • Under Performance, choose your graphics processor rather than the CPU as the AI Processor.

  • Under Allowed Memory Consumption, choose High.

These two tweaks should make a big difference, and the software is being upgraded every few months, so I expect the performance to improve in future.

Bulk editing

If you have a lot of files to get through, then you also have the option of bulk editing them.

All you need to do is check that your default settings are correct and then drag all the files into the main window from Finder or File Explorer.

This is obviously quite a convenient time-saving option, but I never use it because it’s just too risky. I want to make sure that every single image is perfect, and I don’t trust the software to do that…yet!

I guess you could go through the resulting denoised images one by one and check the results, but I prefer to work on one image at a time and watch TV or something while each file is being saved.

It used to take a long time, and I usually upload my images to stock agencies in batches of 100, so that didn’t really work for me.

The latest version of the software saves images a lot faster, but I’m going to stick with my existing method for now.

Watch out!

DeNoise AI is a very good product, but it helps if you know its limitations and how you can get the best out of it.

Here are a few hints and tips:

  • For best results, work on the uncropped image. Sharpen AI and DeNoise AI work best when they have the maximum number of pixels to play with. Most of the time, it doesn’t really matter, but I recommend cropping the image in Lightroom after you’ve sharpened or denoised it if you want to be extra careful.

  • Don’t do any noise reduction in Lightroom. It’s just not necessary.

  • Reduce noise before sharpening in order to avoid ‘sharpening the noise’. In Lightroom, it doesn’t matter if you add noise reduction before you sharpen because the software ‘knows’ what it’s doing. However, Sharpen AI and DeNoise AI are separate programs, so that doesn’t apply if you use both of them on the same image. Again, this is not a big deal most of the time, and of course both programs have sliders for noise reduction and sharpening, but it’s something to bear in mind if, for instance, you want to produce a large format print.

  • Quit DeNoise AI before re-uploading a file you’ve just edited. If you notice something wrong with your image in DeNoise AI, close it, fix it in Lightroom and then re-export it to the same folder, DeNoise AI will display the previous version. It only switches to the new version if you quit DeNoise AI and then open it up again.

  • Be careful of memory usage. DeNoise AI is very demanding of system resources. Other programs will slow down while files are being saved, and if you sharpen lots of files one after the other, you’ll probably find that your memory usage shoots through the roof! At that point, you can either shut down and reopen DeNoise AI or clean up your memory by using a program such as Dr Cleaner (on the Mac).

  • Use masking if you just want to work on a particular part of the image, such as the background. There’s a Mask button at the bottom of the main window. If you click it, you can manually ‘paint over’ the parts of the image that you want the sharpening and noise reduction algorithms to work on. There are various options to change the brush, including the Radius, Softness and Opacity, and you can also make it Edge-aware (the equivalent of Auto Mask for Lightroom adjustment brushes). To save time, there are also four settings for the masking tool in the Options dropdown menu at the foot of the window:

    • Fill. This fills the entire frame with the mask so that you can just erase the bit you don’t need in Sub (ie Subtract) mode.

    • Invert. If the mask needs to occupy a large chunk of the image, you can select the bit that you don’t want and then simply click Invert to reverse the selection.

    • Clear. This clears the current mask if you want to start again.

    • Delete. This deletes any mask and returns you to the main window.

Masking brush

  • Use DNG or TIFF as your default file format. DeNoise AI can’t save images in manufacturer-specific RAW formats such as .NEF for Nikon users. If you open a .NEF file and choose Preserve source format, you’ll just end up with a generic DNG RAW file.

  • Make sure you check the file size after saving. DeNoise AI can easily double the file size of an image, so just make sure that’s not a problem. Most stock agencies have a limit of 20-50MB, for instance, so I simply export all my sharpened images in Lightroom using a preset that limits the file size to 19.5MB.

  • Don’t go too far! It’s very easy to become obsessed with noise reduction and think that you’ve ‘succeeded’ if everything’s beautifully smooth. Just remember that your images still have to have detail in them - especially if you’re a wildlife photographer like me - so you might have to dial it back sometimes. Noise reduction isn’t everything.

  • Save the denoised image into a different folder. If you choose the Source directory, then DeNoise AI can’t replace the existing file it’s working on, so you’ll have to rename it manually afterwards. If you go to Preferences, you can choose Default filename prefix, Default filename suffix or Append processing mode as suffix from the Save Options. Personally, I just delete everything in the text boxes and deselect the other option, but the program then adds ‘ (1)’ to the filename instead. This is not a big deal, and it’s a bit like the restrictions on exporting from Lightroom, but it pays to get your workflow right if you’re denoising a lot of images. Alternatively, you can simply drag files on to the icon in the Dock (if you’re using a Mac), and all changes will be saved to that file without any suffix being added.

  • Set your default preferences for saving files in Lightroom and DeNoise AI. Personally, I like to save denoised images as TIFF files if I’m editing in DeNoise AI from Lightroom, but I prefer to stick with JPEGs if I’m just denoising the exported files I want to upload to stock agencies. Fortunately, you can set the appropriate defaults in both programs so that you’re not constantly having to change them for each image. (You can also deselect the Auto-Update Preview option in Preferences, but you shouldn’t have to after the latest release unless you have a very slow computer…!)

Lightroom Preferences

DeNoise AI Preferences

Conclusion

So there you go.

Just to recap, I think DeNoise AI is a brilliant tool to have in your bag. As a wildlife photographer, I often find myself taking pictures in very low light at high ISOs, and this program allows me to ‘rescue’ dozens of images that would be unusable or just plain embarrassing otherwise.

Try it out for yourself. If you like it, you can get 15% off any purchase by following this link and using the discount code nickdale15.

Good luck…!

If you’d like to order a framed print of one of my wildlife photographs, please visit the Prints page.

If you’d like to book a lesson or order an online photography course, please visit my Lessons and Courses pages.