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Scanning 400H and Green Dots

RattyMouse

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I notice in a LOT of my scans of Fuji 400H negatives, that in the darker areas of the image, a hint of green dots are present. If I boost the shadows, even a tiny bit in Photoshop Lightroom, an ENORMOUS amount of tiny green dots appear all over the darker areas. Absolutely ruins the image. Essentially, my images shot with 400H have no ability to be boosted if they are even slightly underexposed due to the appearance of these green dots.

I see this also, but to a lesser extent, in images shot on Reala film.

I dont really see this in shots made on Porta 400.

Does 400H just scan poorly or is something else going on? What are these green dots then?

Thanks!
 
L Gebhardt said:
Are they on the negative? I haven't shot 400H in a while, but I don't remember ever seeing this problem. However I've only shot a few rolls of it.
Click to expand...

I dont know as I dont own a loupe. I am going to try to get an optical print of one of these negatives to see how they look. I strongly suspect that this is a scanning issue. I dont know if the scans I have are bad or 400H is a poor scanning film. Since I also see this a bit in Reala but not Porta, I dont know what to think.
 

I'm tempted to suggest digital noise particularly as it appears in the dark areas but I'd expect noise to show up in all scans not just those from Fuji negs since it can only be introduced by the scanner. Random thought only, you mention "boosting" in LR - could you also be overdoing the curves/levels in the scanning software for the Fuji frames? This can cause noise in the shadows big time particularly if a bit of neg underexposure exists.

Years ago in my early digital days I used to regularly scan 35mm colour negs of weddings and found that I got the best results by scanning without any curves/levels adjustments in the scanner, preferring to do all that work in Photoshop. Noise was often a problem particularly with dark suits on a neg that was a bit underdone and trying to do any sort of colour/density correction during scanning just made it worse. I think a lot of people would hold the view that the best scan is often one that looks a bit flat because it can be worked on later using better software. OzJohn
 

I am not doing the scanning as they come from a lab. It is quite possible that they way the scans are being done introduces this strange phenomena. It is hard to explain why I only see this mostly in 400H film. That part puzzles me.
 
I would assume that what you see is scanner noise. Note that a few LSB of noise show up a lot more in dark regions. If you can find a way of desaturating dark areas you might have a good chance to tackle this issue for good.
 
Here is my experience:

1. Don't underexpose colour negative film. When in doubt I almost always add a few stops. Underexposed shadows on colour neg are something I find very hard to work with

2. Make sure you aren't clipping any of the channels when you scan. There will be no way to get a decent inversion of the neg if any of the colour channels are clipped at either end

3. If in doubt about the inversion done by your scanner software in "negative" mode do a "positive" scan in linear gamma and invert using Photoshop or the ColorPerfect plugin

4. If using the ColorPerfect plugins make sure you change the black and white clipping thresholds as the defaults clip too soon and will give you crushed and speckled shadows as well as clipped highlights

Hope this helps. This is all applicable to all colour neg material, not just Fuji Pro 400H.

Sam
 
All good stuff if you're a scanning guru but I believe that the OP who has the problem has stated that the offending scans came from a lab. Perhaps having a couple of them rescanned somewhere else will confirm or eliminate the scanner as the problem. OzJohn
 
Yup, have them scanned elsewhere. Also, look at the negs, do they look very thin?
 
I see the same green dots in all my scans of C41 film. I've never had a drum scan done and my scanners are low-budget mass-market. Recently I think I figured out where those green dots come from. As I recently scanned some as positive 48 HDR TIFF files from Silverfast with my Plustek OpticFilm 7400 and then inverted them in PS, I discovered that as soon as I adjust the levels the green dots appear in the shadow areas. The histogram before adjustments show a very narrow range of values for negative color film, thus cranking up the level adjustments for normal contrast really pushes the limits on what my scanner can get out of color negative film. I love the Fuji Frontier SP2500 and SP3000 scans I get from a minilab though. This scanner is definitely in another league as far as noise and Dmax is concerned compared to my own scanners.
 
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