Noise in negatives and slides

Hi everyone, I’m just getting started on my scanning project so I’m hoping that there are some simple answers to my questions. I’m seeing what I associate with sensor noise in the digital world in my “scanned” negatives and slides. My setup is summarised as:

Nikon Z6
60mm AF 1:2.8D micro Nikkor, set at F8
ISO 100, with a shutter speed of about 1s
Nikon ES-1 and ES-2
Kaiser slimlite plano as a light source, positioned about 50mm from the slide

I wasn’t expecting to see the speckling that I get, I hadn’t associated that with film, even with the age of the images, 40 years or more in some cases.

Any help or advice would be much appreciated.

Personally I’m not clear whether the image that you have posted is just a small section of the original, and if that is from a colour negative or slide? Clearly it looks terrible but I would have thought that you could examine the original with a magnifier to compare it with your scan.

Hi Harry, yes the image is a small section to show what I see. This is another example:

They are both converted from negatives.

Thanks, would it be possible to post a low res version of the entire frame just to make it clear how small that first section is and where it is positioned in the frame, and if possible what film you are ‘scanning’? In fact from this latest example it does look to me what you would expect to see, the ‘grain’ looks sharp.

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Have you inspected your originals with a loupe? Magnification of a bout 8x to 10x will do. Whatever grain you’ll see will make it to the scanned image…

In order to see what is real and what is expectation, take a few images and take repro shots with different f-stops and scaling. Inspecting an unexposed piece of film might help too. Also play with Lightroom’s noise reduction settings and see what different settings do.

Could you share a screenshot of the histogram with NLP profile set on the image? Colour noise is often introduced when the scan is underexposed.

Having noise on a thin negative is common but colour noise is mostly introduced/amplified during scanning.

The Kaiser light pad is also not very bright. Having the negative 50mm above the light source reduces light even further.

Thanks everyone for comments, Attached is the full size of the first image. Some questions please, if I may:

  • How close should I put the Kaiser Pro to the ES-2, can I put it within a few mm of the white diffuser?
  • Is shutter time important, I’m running at about a second to get the right exposure. I assume sensor noise related to the sensitivily/ISO setting, not to the shutter time? Peopel do very long exposures for astronomy.
  • I’m adjusting exposure to give a histogram with the channels all distributed from left to right, not pushed over to the right or falling off the edge.
  • Richard.

The fullsize version of the second image.

Thanks for doing that, it certainly helps me to see what proportion of the negative you were showing here, and in fact in both cases it’s a pretty small part of the whole frame. For me what you are seeing is quite normal and not down to anything in your technique or setup. I think it’s just what negative film looks like close-up when you’ve turned it into a positive, whether in NLP or in some other way. As has been said you could perhaps play around with noise reduction to minimise it but I don’t think that it’s noise as such, just the way negative film records the image. I’ve noticed this myself in particular when scanning and inkjet printing a well-exposed and sharp 35mm negative that I have already printed in the darkroom back in the day. I used to print hundreds, probably thousands, commercially and I kept some of these prints as a reference. The darkroom prints don’t really show this noise/ grain but the scans printed to the same size on a high quality ‘photo’ inkjet seem to accentuate it. I’m not just talking about 24MP camera scans, the same is true of Imacon Flextight scans or those from a 4000 ppi film scanner.

But - I’m talking about very closely examining 16" x 12" prints side by side, something only photographers tend to do.

Hi Harry, that’s interesting and good to know. I wonder if I’m at too high a resolution, and there is a need to apply a bit of filtering/averaging needed to get at or below the size of the film grain.

I tried some experiments with the LR de-noising but it had very little effect, I’ll try some more once I’ve read a bit about how LR works.

What I’m concerned about is that the grain is generally quite visible in the scans I’m doing but perhaps the process of turning the scanned images into print will effectively soften things out.

  • Richard.

Personally I think that’s the way to go, it will depend upon how big the prints are (and how close you look at them!) but I think that this pixel-peeping might be giving you a false impression of how the prints will appear in practice. I don’t think you are capturing too much detail, you can make a case for capturing 35mm with many more megapixels than this, and your lens is good. I don’t have a microscope but if I did I might be tempted to have a look at a spare frame or two through one of those, or a just a high power loupe.

There’s been some discussion of this on a particular stock photography forum where the quality control is pretty strict. The aim there was to upload a scan (admittedly normally of a transparency) so that Quality Control didn’t pick it up as a scan. The consensus was that the best way was to selectively use something like Topaz, but to downsize to around 6MP (3000 x 2000 pixels), the minimum file size for that library. It is going to depend a lot on the original though.

One thing that interests me, but I don’t have an answer for, is that if you ‘scan’ a transparency there is a tendency for the contrast to increase slightly so you can usefully knock back the contrast a little in post processing, possibly by reaching into the shadows and highlights. However if you scan a colour negative you have to really boost the contrast at some stage. This is particularly obvious if you try and do the conversion/inversion manually in Photoshop, so you neutralise the mask and then invert. I have wondered if that is where this accentuation of the ‘grain’ comes from with colour negatives. Perhaps someone can enlighten me.

You can easily reduce distance to 5mm. This should increase the light significantly. The pad has been designed to lay things flat out on it. The diffusion panel of the ES-2 is also still there, so don’t worry for that.

As for the histogram: You may want to expose to the right for negatives (+1 stop is definitely safe). For slides, that’s a different topic and depends on your further workflow (colour profile, etc). If you don’t want to make it a science project but just enjoy your photos, keeping it as wide as possible is good.

Try with the additional diffusor removed.

I’ve shot 645 negatives laying flat on a Kaiser without issues other than dust.

The ES1/2 shouldn’t suffer any problems from slow shutter speeds compared to a setup where the camera and lens are suspended over the target slide and light box, so you might try a slightly longer exposure just to see if it makes a difference. The other big advantage of the ES1/2 is that correct alignment is guaranteed without fussing around with mirrors and/or spirit levels. Looking at mine it seems that the diffuser can be removed easily as the threads for the two machine screws go all the way through, I’ve always thought it was a bit close to the slide in terms of the potential for dust etc. anyway.

Your first sample crop of the street scene is about 6" across on my screen, so the equivalent full frame image would be around 30" across, pretty big if you loosely compare that to print size.