Scanner noise in shadows?

[John]

I am finding some scanner noise or something in the dark areas I scan. I am using a Plustek 7200, set at 3600 dpi, first save as a 48 to 24 bit colour tiff. The film is Fuji Superia 400. The test shot used is from my M3 with Serenar 50/1.8. No Photoshop tweaking except for jpeg conversion.
You can see the noise in the dark shadow area. If the picture is all dark you get all noise? Has anyone seen this before? Any suggestions?

 

[Spyderman]

Well, I have a Minolta DSD III scanner, but it produces much noise in areas that are dense on the film (highlights on negs, shadows on slides). It is just that the light cannot pass through the material on the film, and the sensor records just the ordinary digital temperature noise (just like digi-cams).

I suspect that the noise you are getting in shadows from negs, might be the film grain. ISO 400 is pretty grainy also on my scanner with only 2700 dpi, and you are scanning at 3600. So I vote for film grain

 

[kaiyen]

It is also quite common to see what in areas of underexposure. If it's really underexposed, you're getting noise from the scanner trying to eek out the last bit of detail there.

allan

 

[aad]

Does your scanner support multi-pass? That can help if it is scanner noise.

 

[sf]

many scan utilities do allow multi pass scanning, and that will average out the scanner noise issues in those areas.

I have noticed, though, that such a look may not be actual noise. I can scan a B&W or color neg many times on separate passes and see the same exact "noise" pattern which leads me to think that the scanner is simply seeing the shadow that way.

Vuescan - as much as I dislike it - does allow you to do either single pass multiscanning or multi pass multiscanning (for scanners that don't do the first one).

 

[kaiyen]

I've had Vuescan do...like 24 passes on some negatives and still get that noise. As George says, that must be something in the negative itself, the dye pattern (commonly referred to as grain but there is no such thing with c41 film) or something. In those cases where it's not noise, a bit of noise reduction can help. Then, worst case, just use levels to cancel out that area. It's usually in the blacks anyway. You'll just lose more shadow detail.

allan

 

[Ukko Heikkinen]

Hi

You should always meter the deep shadows in order to avoid scanner noise. If you use Ilford XP2 at 200 ASA, even the highlights of contrasty subjects won't be blown out/grainy.

Ukko Heikkinen

 

[John]

Thanks guys, I feel a lot better now. It appears as though this noise is relatively common. I can now tweak around it as best as possible and let you know what I come up with.

 

[John]

So far I have tried scanning at 1800 dpi and 600 dpi to see if it is grain showing. It looks to be not grain because the noise is still there in the same amount etc. I also checked and my version of the software does not support multipass scanning. I am trying to scan in raw mode now and have another thread about this in Photoshop.

 

[Socke]

I'm away from most of my pictures so can't post a sample.

I had this with Kodak Royal 800 and Fuji Superia 1600 shot in near darkness, concerts and theatre.

Slower films don't show this except the Elitechrome 400 I shot late in the evening in Madrid. It has an ugly green cast in the shaddow areas and some noise too.

 

[kully]

I get the same noise with Superia on my Nikon V ED, 24 passes in Vuescan make no discernable reduction.

It's a C41 thing, try E6 film and you'll be amazed.

 

[John]

Thanks kully. I will try some E6 and B&W in the future sometime. I have years of exposed C41 I am trying to scan with or without noise. I am learning all this new to me equipment and figuring out a workflow. For example do I need 48 meg tiffs if my limiting factor for quality is noise? A 7 meg jpeg shows the same noise.

 

[kully]

John, I'm doing exactly the same as you - I think I'll be scanning for a long, long time.

What I'm doing is scanning in at the bext quality with DICE to TIFF. Then converting all the TIFFs to JPGs and saving the two formats in different folders on the same DVD. The JPGs are easily accessible and I know that I got as much detail from the frames in the TIFFs as I could - in case I want to muck about with them in the future.

EDIT: Forgot to say, if you want to get rid of that shadow noise, try Noise Ninja - it works well, but it can give a 'plastic' sheen to the resultant image.

 

[Socke]

TI am learning all this new to me equipment and figuring out a workflow. For example do I need 48 meg tiffs if my limiting factor for quality is noise?

I scan 24bit TIFF for archival and editing purposes so I don't have to rescan when I want to try anything on the original and I can make CMYK seperations as well as RGB jpegs from 24bit tiffs.

I often use multipass to get around certain limitations of my scanner but not more than 2x, it doesn't get better with more passes just takes longer.

Very seldom I rescan in 48bit Tiff with more than 2 passes when I have a neg which needs the work and is worth it.

 

[John]

Socke; Is a 24 bit tiff also known as 8 bit colour? 8 bits for each of RGB. The reason I am asking is because the least expensive Noise Ninja version supports 8 bit colour and the professional version does 16 bit.
I would be able to archive in 24 bit as you said you do. The consumer version of Noise Ninja would be fine with this workflow I believe? I just tried the demo version of Noise Ninja and it is doing quite a good job reducing noise, compared to a few other things I have tried.

 

[rich815]

Vuescan - as much as I dislike it - .

George, are you not the same person who only a day or two ago complained about Vuescan because of the noise it made with your scanner, and lamented not downloading and using the trial version first? With all due respect, based on that very limited experience with Vuescan you feel you can pass judgement on it? How can you know whether you "dislike" it in terms of whether it's a good program or not? At least qualify your dislike for what it is: it's makes your own personal scanner make a distasteful noise. Otherwise people may think you actually have a dislike based on some kind of actual experience and use of the program for more than a day or two. Your comment seems to imply some kind of opinion based on enough use of Vuescan to form a viable opinion, and I do not think that's very fair based on you post yesterday.

 

[HansDerHase]

I don't think that what we see in the scan's dark areas is thermal noise of the CCD.

Looks more like a posterization effect (scanner operating at the edge of its value-range; try scanning the dark area with different exposure-setting - making the dark area 18% grey - combining in photoshop later) and/or density effect (scanner operation at the edge of its density-range; can not do much about this).

Those effects tend to look especially ugly when grain-pixel interference kicks in, which happens at around 400 ISO C41 (scanning 3200 w/ SD IV). This interference is due to the fact that grain is unevenly distributed while the pixels from CCD-array are evenly distributed. Grain-pixel interference leads to ugly patterns when the size of the grain is just about the physical resolution of the scanner (CCD+stepper). To avoid interference-patterns one would have to scan at considerably more (> 6400 dpi) or considerably less (< 1600 dpi). Where less unfortunalty means physically less, not just throwing away pixels by (scanner-)software!

Some say that one can fool the scanner for a lower physical resolution by scanning out of focus (manual focus). But I haven't tried that.

Interestingly Sensia 400 scans very smooth for me while Superia 400 usually scans plain ugly.

Sometimes negatives that look very similar in respect to grain whe inspected by a 10x loup scan very differently (usable_for_small_print / notusable_even_for_web).

 

[Socke]

Socke; Is a 24 bit tiff also known as 8 bit colour? 8 bits for each of RGB.

Exactly, there are 8bit per chanel, 16bit per chanel and, if available from the scanner, a version with a 16bit IR channel added to RGB.

 

[sfb_dot_com]

Doesn't actually look too bad to me if that is a 100% crop. Otherwise it's a combination of the exposure and/or grain aliasing. The tip about exposing for the shadows is a useful one if you want shadow detail, or if not so necessary you can use PS Levels/Curves to deal with it another way.

Regards


Andy

 

[John]

Update
See what you think of this scan now. I have wiped out most of the shadow noise with contrast adjust. Just to be sure I rolled it through Noise Ninja. I am very happy with this compared to what I started with. It can only get better with experience.