Is there any way to reduce grain in a negative scan?

EricTheReddish

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I haven't seen this question posted recently, so... In my scanning journey, I of course have noticed the film grain that comes along for the ride when you scan the negative. It occurs to me that there's a lot of software that will reduce image noise in digital images, but I don't recall having seen any that deals with analog grain, which is a different animal.

So... is there software that can address analog grain? Doesn't have to be drastic or perfect, just bring it down a notch (or two). Most software that contains a "noise" feature seems to want to add it.

Thanks!

P.S. Doing a web search for "reduce grain in images" brings up an alarming number of articles/videos on how to reduce noise even though they're calling it grain. Apparently, some people think they're the same thing.

Edit: Critical missing piece of information: I'm looking for B&W not color negatives
 
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loccdor

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Frankly, the best way is to use a lower grain film to begin with. Agfa Scala/HR 50 for example. If you're past the point of already having taken the pictures, noise and grain are pretty much equivalent when it comes to imaging software. Software is going to do a selective blur where two adjacent pixels are close enough in value levels, and refrain from blurring when they're too distant in value levels. It's a very digital effect that I am not very fond of, and even when using digital cameras I keep noise cancellation low as the tradeoff is to make images muddy.
 

koraks

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EricTheReddish said:
a lot of software that will reduce image noise in digital images, but I don't recall having seen any that deals with analog noise, which is a different animal.
Click to expand...

Well, yes, the pattern is different, but arguably, not all digital noise is the same either, and the same goes for grain. Ultimately, they're all 'noise' in a generic sense. Moreover, the grain you see in a scan is in fact a combination of the actual film grain and the optical and digital 'signature' of the scanner - so it's not pure analog grain (or noise), really - it's an amalgam of film grain and digital artefacts. And the fact that noise (as heterogeneous and complex as it may be) is in the end still, well, noise, is relevant, because it also means that noise-reduction tools present in photo editing suites will in fact reduce noise.

The problematic side-effect is that they also tend to smear out fine detail. That's a clear case of "can't have your cake and eat it", I'm afraid. However, it's possible that the modern AI-assisted noise-reduction or image-enhancement tools in recent Photoshop versions can actually combine continued possession of patisserie while at the same time consuming it, to an extent. You'd have to experiment.

In GIMP, there's a very rudimentary noise-reduction filter:

Shown is a 100% crop of a 3200dpi scan from a Fuji NPS160 negative. Note how the grain is suppressed - and also how detail gets smeared. Filtered area shown left of the dashed line, original to the right.
As said, suites like Photoshop may have more advanced noise-reduction tools that will retail more detail/crispness while suppressing noise (scanned grain etc.) quite effectively.

Scanning software often also has similar noise/grain suppression tools, but they invariably come at the cost of fine detail as shown above. I personally never use them because I don't see the point in throwing away scanning data right from the get-go. Maybe new versions of VueScan have more effective noise reduction tools than the ones I'm used to from eons ago.

Finally, coming back to the 'scanned grain' aspect: note that it makes a lot of difference how you scan your film. E.g. on my flatbed Epson 4990 I get relatively grain-free scans - but they're also somewhat less crisp and detailed than from e.g. my film-dedicated Minolta Scan Dual IV. So if you want to optimize for low-grain, consider using a flatbed scanner.
 
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EricTheReddish

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My poor brain was not up to the task of posting a well-formed question. I've edited it, and to be clear, I want to reduce analog grain in a scanned image, not digital noise.
 

Kodachromeguy

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Does using the multi-scan function on Nikon Coolscan or Minolta scanners help reduce the appearance of grain? Or does multi reduce the effects of digital artifacts?
 

glbeas

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Unsharp masking can make grain look very harsh if the parameters are set wrong. I’ve found I need to set the radius of the masking larger than the apparent grain size and play with the percentage to get best results.
 

titrisol

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Darktable/negadoctor does an OK job as well in reducing noise and grain
but at the expense of sharpness.
 
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EricTheReddish

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Kodachromeguy said:
Does using the multi-scan function on Nikon Coolscan or Minolta scanners help reduce the appearance of grain? Or does multi reduce the effects of digital artifacts?
Click to expand...

I do use the multi-scan on my Epson V700
 
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EricTheReddish

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glbeas said:
Unsharp masking can make grain look very harsh if the parameters are set wrong. I’ve found I need to set the radius of the masking larger than the apparent grain size and play with the percentage to get best results.
Click to expand...

I did turn off the unsharp mask in Silverfast, and that did improve things
 
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EricTheReddish

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EricTheReddish

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titrisol said:
Darktable/negadoctor does an OK job as well in reducing noise and grain
but at the expense of sharpness.
Click to expand...

Most noise reduction algorithms do reduce sharpness. But, like mentioned before, I wonder if the software knows the difference between digital noise and film grain.
 

Alan Edward Klein

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koraks

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EricTheReddish said:
I wonder if the software knows the difference between digital noise and film grain
Click to expand...

How could it? From a signal quality perspective, it's the same. Yes, there are Qualitative and quantitative differences between types of noise, but there's nothing to film grain that makes it fundamentally different from other forms of image noise. It's a density deviation with a certain frequency bandwidth that occurs in one or more color channels. Scanned grain is just a subset of noise. Thus, the tools/filters available for noise suppression can be used to suppress the noise resulting from scanning grainy film. The tricky bit, it seems, is accepting that this is the case.
 
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EricTheReddish

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Not tricky at all, since the software is geared towards digital images, whatever algorithms they use simply wouldn't apply to analog noise. They might help, but it'd be more of a coincidence than anything. Hence, my original question.
 

MattKing

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EricTheReddish said:
Not tricky at all, since the software is geared towards digital images, whatever algorithms they use simply wouldn't apply to analog noise. They might help, but it'd be more of a coincidence than anything. Hence, my original question.
Click to expand...

Once the signal gets to the software, it is all digital noise anyways, because by then the information is in digital form.
In order to differentiate between various forms of digital noise - for example the digital noise arising from the sensors and firmware vs. the digital noise arising from digitizing the patterns in film - one probably requires some pattern recognition tools.
It would be difficult to design those tools for general application, because the results of digitizing film grain vary with light source, optics, sensors and firmware.
Something like the scanners used in the motion picture industry might be targets for that work, due to the film volumes each machine is used with, but I'd be surprised if that work would be done, due to how motion picture images are displayed - moving images hide a lot of grain or noise.
 

brbo

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Too much grain from a flatbed? You scanning film or Legos?

OP would spare us a lot of guessing with just one example of this "grain"...
 

loccdor

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As Koraks said, random speckling on an image, whether it's coming from a digital or physical/chemical process, is going to be a very similar phenomenon. The distinction has less significance than you are giving it in an image processing context.
 

runswithsizzers

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When I first started scanning film with my film scanner (a Minolta Dimage Scan Elite F-2900), I was seeing a lot of what I thought was over-prominent grain in my scans. After doing some reading, I think what I was seeing was not, strictly speaking, film grain, but rather grain plus an artifact of the scanning process. Some articles refer to this phenomenon as "grain aliasing" -- which you can use as a search term to learn more about it. By trying out different scan settings in VueScan, and different sharpening settings in Adobe Photoshop and Lightroom, I was able to reduce the effect to a more tolerable level.

However, since I switched from using a film scanner for copying my negatives to using a digital camera, I have been much happier with the appearance of the film grain. For whatever reason, the grain as seen on my camera-scans looks a lot less "gritty" a lot more natural.

EDIT: Here is a link that presents the case for "grain aliasing" -- what it is, and what can be done about it:
 
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MattKing

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FWIW, one of the reasons that film grain looks more obvious from a scanner than it does when using a camera to digitize the image is that the nature of the light and the optics employed in both approaches differs greatly.
Camera "scanning" is likely to employ much more diffuse light, and there is a much higher likelihood that flare will be induced.
 

joho

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There is is a deep miss-conception on this theme, all scanners CCD types use electronic signals to recreate the image and thats the GLICH !!!
I will not go into detail but, it is that simple ---
 
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