Noise Reduction Software

Scan

Correct Color

Smooth Texture

Reduce Noise

Remove Dust

Repair

Crop

I have been quite happy with Photoshop's Reduce Noise filter for my scans. I've been using it over the years, until one fateful day I was reading up on noise filters. I was researching the proper order in which to use noise filters and dust filters, when I came across reviews of various third party plugins to remove noise. Topaz DeNoise kept popping up as a popular favorite. Nik Dfine was also notable, especially since the Nik collection was recently acquired by Google.

Reviews I've seen were written by people who used noise filters on images taken with digital cameras. Since noise filters may work differently with scanned photos, I wanted to see for myself how well they work for my purposes. So I do what I do best, I test and test.

Clean Up in Aisle 4

Let's clean up those noisy photos! This is a comparison test for noise filters. For this comparison, I used one black&white and eleven color photos containing different kinds of noise. The photos range from light noise to heavy, blocky noise. All photos had a smooth untextured finish.

Testing was completed in September 2017 on macOS 10.12 and used these filters:

Photoshop Reduce Noise. Photoshop Elements version 15 (Oct 2016)
Nik Dfine. Version 2.2 (Mar 2016)
Topaz DeNoise. Version 6.0.2 (Mar 2016)

I tested Photoshop Reduce Noise, Nik Dfine, and Topaz DeNoise on each test photo. After trying different settings for each noise filter, I noted which settings appeared to work the best. I recorded the time it took to use a filter on each photo including the different settings that I tried. This should represent real-world usage more accurately. Times were rounded to the nearest 5 seconds.

Descriptions of settings for each filter follow:

Photoshop Reduce Noise: This filter is very easy to use and has 3 settings: Strength (s), Preserve Details (d), and Reduce Color Noise (c). Strength is the overall strength of noise filtering, and is usually between 4 and 10. Using Preserve Details helps retain small contrasty details such as eyes, teeth, hair, etc, and is usually 0, 10, or 20. Higher values retain slightly more detail and a lot more noise. It's best to keep it as low as possible. Reduce Color Noise is usually 100 for photos with lots of discoloration, 0 for photos with no discoloration, or something in between.
Ex: "s=8, d=10, c=0" means Strength set to 8, Details to 10, and Reduce Color to 0%
Nik Dfine: This filter has a learning curve, but is easy enough after learning how. When staring Dfine, it automatically analyzes a photo to find rectangles of various colors in different parts of the image. These generated rectangles should contain noise but no details of any kind. Any such rectangles that contain details should be removed by the user. Any distinctly colored areas of the image that have no rectangles can have one added by the user. After rectangle creation, either the contrast noise or the color noise or both can be set from 0% to 200%. In the table below, the first numbers are the amount of rectangles added or removed, and the percentage indicates the contrast noise.
Ex: "+2-1, 120%" means 2 rectangles added, one removed, and Contrast Noise set to 120%
Topaz DeNoise: This filter has a lot of settings, but the user can select a single preset rather than making over a dozen individual settings. Once a preset is selected, the user can adjust a setting or two (or more) if needed. Settings include overall strength (str), highlights, shadows, red, and blue. Raising a setting increases the noise filter strength for that particular setting. In the table below, the first word (such as stronger or moderate) represents the RAW preset. This is followed by other settings (such as highlights or blue).
Ex: "strong, blue=.5" means RAW Preset set to strong, Blue set to .5

Test settings and times (shown in brackets) are in the table below, followed by my observations.

Description	PS Reduce Noise	Nik Dfine	Topaz Denoise
Allies Game: noisy inc. wall & skin	s=8, d=20, c=0 [95]	0, 100% [80]	strong, hi=0 (was -.6), blue=-1 (was .07), red=-1 (was .14) [175]
Backyard Slide: noisy esp. grass	s=10, d=10, c=0 [65]	+3-1, 150% [95]	stronger [65]
Bald Chair: very noisy esp. wall	s=10, d=10, c=0 [45]	0, 120% [90]	strongest, highlight=0 (was -.41) [110]
Birthday Face: noisy esp shadows	s=10, d=10, c=0 [95]	0, 200% [100]	stronger [90]
Clean Rug: coarse noise, blurry	s=10, d=10, c=0 [40]	+2, 120% [85]	stronger [60]
Color Coat: film grain	s=7, d=10, c=0 [60]	+2, 100% [160]	stronger [75]
Court Kids: noisy	s=8, d=10, c=0 [85]	+2-1, 120% [130]	strong [95]
Crossed Legs: tiny scratches & dots	s=6, d=10, c=0 [90]	+2, 100% [145]	moderate, shadow=.1 (was -.08) [140]
Cup Cigar: very coarse noise	s=10, d=10, c=100 [50]	+2, 200% [165]	strongest, highlight=1 (was -.57) [75]
Custom 250: noisy	s=6, d=10, c=0 [110]	0, 120% [75]	stronger, highlight=0 (was -.69) [135]
Deer Camp: noisy, no fine detail	s=10, d=10, c=100 [60]	+4, 70% [125]	moderate, str=.11 (was .13), highlight=.2 (was 0) [120]
Kids Backs: noisy, has facial detail	s=10, d=20, c=0 [65]	+3, 130% [105]	strongest, shadow= -1 (was .16) [150]
Ottoman Family: very noisy esp. wall	s=10, d=10, c=100 [55]	+2, 150% [180]	strongest, highlight=0 (was -.55) [95]
Phone Gals: blurry & noisy	s=10, d=10, c=0 [55]	+2, 150% [95]	stronger, highlight=0 (was -.47) [125]
Pickup: noisy esp. sky & hood	s=10, d=20, c=0 [100]	+2-2, 100 [180]	strong, highlight=.2 (was -.22) [175]
Reno Lion: bit noisy, fine fur detail	s=6, d=20, c=0 [85]	+2, 80% [155]	moderate, shadow=0 (was .14) [130]
Season Greet: noisy with blue sky	s=10, d=20, c=0 [90]	+3, 100% [150]	strong [90]
Shed Work: noise on windows	s=6, d=20, c=0 [115]	+1, 120% [100]	moderate [210]
Shelf Tree: fairly clean, noisy wall	s=6, d=20, c=0 [65]	0, 100% [95]	moderate, highlight=.3 (was -.74) [135]

Observations for Photoshop Reduce Noise:

Strength: I used values from 6 to 10. (Generally should be 4 or higher.)
Preserve Details: 10 worked in most cases. 20 when more details needed to be retained.
Reduce Color Noise. For most (16 of 19) of these untextured photos, 0 was fine.
Average time to filter test image was 75 seconds.

Observations for Nik Dfine:

For best results, I usually added rectangles and sometimes removed them.
Increased Contrast Noise strength helped with very noisy images.
Varying the Color Noise strength did not have much effect, so it was left at 100%.
Average time to filter test image was 122 seconds.

Observations for Topaz DeNoise:

Increased Highlight helped with noisy walls.
Increased Blue helped with noisy skies.
Decreased Shadow helped with retaining small details (eyes, teeth, fur, etc)
Increased Grain helped with adding texture to images without fine detail
Average time to filter test image was 118 seconds.

After I was finished with all the tests, I compared the images and summarized my opinions in the following table and conclusions. Best results and ties are highlighted in green .

Description	PS Reduce Noise	Nik Dfine	Topaz DeNoise
Allies Game	clean, wall mostly clean, skin extremely clean	clean, wall mostly clean, skin extremely clean	clean, wall mostly clean, skin very clean, retained most board game detail
Backyard Slide	sky & houses & grass still half noisy	sky & houses & grass clean, details mostly lost in sidewalk, very clean fence boards	sky & houses & grass clean, edges of yard toys refined and clean
Bald Chair	mostly clean	very clean, wall extremely clean	very clean, round lamp base smooth
Birthday Face	noise softened, but most noise remains	fine noise mostly gone, some coarse noise remains	all noise mostly gone, coarse noise on face now smooth, edges of eyes slightly blurry
Clean Rug	mostly clean	mostly clean but looks slightly pixelated, tweed chair lost half its detail	mostly clean, smooth face & hands, door jambs have good edges
Color Coat	clean face, clean walls	clean face, very clean walls	clean face, very clean walls
Court Kids	noise half gone	noise mostly gone	noise mostly gone, hair cleaner & more detailed, faces smoother & more refined but whites of eyes slightly less noticeable
Crossed Legs	most noise gone	most noise gone and some very light scuff marks gone	almost all noise gone, most very light scuff marks gone
Cup Cigar	noise half gone	very clean	extremely clean, shirt and other edges refined
Custom 250	noise half gone	almost all noise gone	almost all noise gone, noise cleaned up along edges (chrome, reflectors, etc)
Deer Camp	noise half gone, color noise gone	ugly noise gone, dirt road has pleasing film grain look	almost all noise gone, smooth deer fur, sharpened foxtails, dirt road looks watery though (mostly due to lack of natural texture)
Kids Backs	noise over half gone, faces a bit rough, fence edges slightly rough	noise mostly gone, faces a bit rough, fence edges slightly rough	noise almost all gone, faces smooth with good details, fence edges clean
Ottoman Family	half clean	slightly noisy bricks & clothes, clean wall	clean bricks & clothes, slightly noisy wall, faces smooth with good details but eyes less contrasty
Phone Gals	mostly clean	clean	clean, edges of hair and clothes very clean and refined
Pickup	almost all noise gone	almost all noise gone	almost all noise gone including sky noise, window clean, straight edges smoothed
Reno Lion	clean photo	clean photo, fine scratches less noticeable	clean photo, fine scratches less noticeable
Season Greet	clean photo, sky slightly noisy	very clean photo including sky	very clean photo including sky
Shed Work	most noise gone	almost all noise gone, window very clean	most noise gone, face very clean
Shelf Tree	mostly clean face	clean face	clean face and wall

The close-ups below are best viewed with this window opened as wide as possible.

Allies Game
before	PS Reduce Noise	Nik Dfine	Topaz DeNoise

Crossed Legs
before	PS Reduce Noise	Nik Dfine	Topaz DeNoise

Custom 250
before	PS Reduce Noise	Nik Dfine	Topaz DeNoise

Pickup Cap
before	PS Reduce Noise	Nik Dfine	Topaz DeNoise

Shed Work
before	PS Reduce Noise	Nik Dfine	Topaz DeNoise

Shelf Tree
before	PS Reduce Noise	Nik Dfine	Topaz DeNoise

Topaz DeNoise took 43 seconds longer on average as Reduce Noise, but the resulting images are spectacular. Rough faces become smooth while retaining most detail, edges of objects become refined and free of noise. And to top it off, Topaz DeNoise is fairly easy to learn.

Once the noise is removed, it's clear that Topaz DeNoise is a keeper!

Diamond in the Rough

Scans of textured prints can turn out terrible. Not only do scanned images have the texture embedded into the images, but noise will often cover the images. This noise is not too apparent when looking at the prints but seems to amplify greatly when scanned. The scanned images may be thoroughly mottled with ugly discoloration as well. Often the discoloration will be a sickly shade of yellow.

FFT noise filters can help with pattern textures, such as prints with regularly spaced rows of thousands of very tiny dimples, all the same size and shape. However, FFT filters can't help at all with random textures which are rough textures without patterns embossed onto photo paper. Only regular noise filters can help with random textures, but many textures can be a challenge to remove.

I had so much success with coarse noise removal with Topaz DeNoise, I set out to see if DeNoise was up to the challenge of removing random texture.

ATC Trailer
before noise reduction	after Topaz DeNoise

My ATC Trailer print has the lightest texture of any of my textured photos. As you can see by the image on the left, even a lightly textured photo is covered by fine noise. This noise makes the photo look dirty. Because the texture was so light, it was easily cleaned by Topaz DeNoise using the "RAW-Light" preset. It looks like the trailer has been washed in the image on the right.

Ironically, that dirty-looking trailer was squeaky clean as I had just scrubbed the exterior of the entire trailer. I vividly remember the chemical burns I got from using a cleaner with bleach. Next time, gloves!

Twinstar
before noise reduction	after Topaz DeNoise

My rather unique Adnoh Twinstar motorcycle. Or rather, a print of my Honda Twinstar, which was developed and printed backwards by the company that processed the film. They used photo paper which had a moderately textured anti-fingerprint surface. The surface is covered in tiny curves which scanned in quite "nicely". Some of the curves came out yellowish and some came out reddish. I would have preferred that they came out clearish.

Settings for DeNoise were a bit tricky to get right for this photo. Simply setting the preset to "RAW-Strong" didn't remove all the noise and setting it to "RAW-Stronger" removed too much detail. When this occurs, I usually set the preset to the lower value and increase the Strength setting. With the "RAW-Strong" preset, the default value of Strength was .18. I increased this gradually until I found a value where most of the noise was removed while retaining most of the detail. For this photo, .22 worked well for the Strength.

Because there was more noise and less detail in the shadows for this photo, I increased the Adjust Shadow setting a bit. I raised it from its default of .44 to .6 and found that value worked great for the shadows.

Finally, I noticed that the result seemed a bit grainy for a shiny motorcycle, so I lowered the Add Grain setting from its default of .15 to .1 which improved the shine considerably without making the image too blurry.

Most photos don't need so many adjustments, but this one did. As you see in the image on the right, the result came out great. The noise is gone, the gas tank looks very shiny, and the edges of the stripes are very refined and straight. Not shown is the ground cover containing thousands of leaves in the back, which have retained their detail.

It was a fun motorcycle but it was hard to get used to the throttle on the left side. Highly unusual, I know, but I have a photo to prove it.

Rake Work
before noise reduction	after Topaz DeNoise

This photo of Rake Work had a very rough surface. As you can see from the image on the left, the photo is completely slathered in coarse, ugly, dotty discoloration. It is the most discolored photo in my family album. Not expecting too much of an improvement, I clicked on the "RAW-Strongest" preset in DeNoise and... What kind of magic is this??

Topaz DeNoise helped make terrible textures a thing of the past... fast.