Posted by Robert Bunch on February 17, 2010 at 1:39 PM
In my fairly limited experience with scanning slides to digital files I am coming to the conclusion that one cannot get very satisfactory results. The scans I am working with are either commercial scans (not low grade comm'l scans but also not the highest quality drum scans) or scans a friend made for me on his nikon super coolscan 4000 ED. These are from 40 up to over 90 meg scans. The results vary with some looking pretty good and some not so hot but as a general rule I like the quality of the dslr files from my old D70 and my current D200 (which are about 17.2 and 28.7 megs respectively)much better than these big scans from slides. The original digital files look sharper and "hold together" better at larger sizes on my computerscreen. Also it is really hard or impossible (at least for me) to get the color to look right. The original slides are all sharp and well exposed. On the few large prints(16X20 20X24) I have made from scanned files I have gotten satisfactory results but most of the scanned files look so mediocre on the computer screen that I am reluctant to have prints made from them.
So,is it just not possible to get as good a quality files from scans from slides and negs as you can from digital camera files or is something else wrong here.
I have a lot of slides and negs I would like to scan and I have been thinking about buying a high quality scanner but with my experience so far I am not sure that it worth it.
Any enlightenment you can give me will be appreciated.
Posted by Mel Ladewig on February 17, 2010 at 3:18 PM
I have largely quite digital capture and now do mostly film + scanning.
It is absolutely possible to get great files from film scans, but don't assume it is easy. Scanning is a skillset completely different than raw processing. But when it is done well, you'll have a great 14-16 bit file to start with.
Slides are in my opinion more difficult to get a good scan. The dynamic range tests the capability of the scanner more than negative film. Its hard to get clear shadow details and keep highlights. In general they seem more difficult to get a scan that looks just like the slide on a table and part of the "problem" is that you can look at the slide on the light table and decide that it doesn't match. I've also seen some convincing discussions that point to slides being less sharp than negative for one reason or another. I've seen some of this in my own scans. IT8 scan targets can automate color correction in slides and are used to calibrate your scanner against a known target. But I think this could also neutralize some of the nature of a film in favor of a particular neutral color profile.
Negatives are easier to scan because the range fits easily into the scanner's ability, but more difficult because the density curves for the three channels do not line up and they are more open to interpretation because you cannot directly see what they "should" look like when reversed.
To get the best files from scans I think you'll need to learn some photoshop tools that you don't usually need to use for digital capture.
I usually find color issues in my scans in the neutrals and shadows. The scanner may shift the shadows to red or green and I need to correct that out (happens alot).
The first tool I would recommend you learn is selective color's white, neutral and black controls. Inside each "color" you'll find a control slider for cyan, magenta, yellow and black. This is an important skill for scanning and can be applied both in photoshop and the scanning software. Once you've worked the neutrals, you may need to adjust a particular color. The transmitted colors Red, Green and Blue are paired with the reflective colors Cyan, Magenta and Yellow. This principle applies to most color editing.
Adding cyan reduces red. Reducing cyan adds red.
Adding magenta reduces green.
Adding yellow reduces blue.
Adding black to midtones or white can increase color saturation. Adding black to black = darker shadows. Subtracting black from white clips highlights.
You can take this same knowledge to curves and have a different set of controls.
Curves are RGB+Black driven. If you go into the red curve and pull down red near the center, you're adding cyan uniformly to the image. Pull up red and you're subtracting cyan. Small changes here go a long way.
The next thing I've found in working with film files versus digital is that the film is going to have grain. It doesn't look bad printed (It can actually enhance enlargements), but it can appear a bit harsh on screen. Smart sharpen makes a mess of film grain. Use unsharp masks instead with the threshold at 1 or 2 and you can sharpen the image without sharpening the grain so much.
Mel-
Posted by Robert Bunch on February 17, 2010 at 4:15 PM
Mel,
Thanks for the detailed and very informative discussion. I can see it is not as simple as I thought and I have much to learn. I'm glad that some of the things I experienced are borne out by your experience such as the difficulty getting good colors and the loss of quality or graininess in slide scanned files and it is good to know that it is possible to get good scans if one knows what they are doing.
May I ask what kind of scanner you use?
Thanks again,
Robert
Posted by Mel Ladewig on February 17, 2010 at 4:26 PM
I have an Epson 4990 and Nikon LS-4000 (Coolscan 4000 ED). I've been toying with the idea of getting a used Howtek D4500 drum scanner, but I haven't quite reached the point where I want to dive completely into the deep end.
Robert, I'm using a Nikon 9000 to scan Velvia (50) transparencies in the 6x4.5 and 6x7 formats, and loving it. Some comments:
- At 4000 SPI (the Nikon's resolution) and even when sharpened, my scan files are soft when displayed on-screen at 100% -- softer than digital camera files I've compared with at 100%. They are also much noisier due to the film grain. This is all because a high-resolution scan is pushing the boundaries of what is actually caught on film, I think; that's just the way it is. But that's comparing scanned pixels at 100% to digital-capture pixels at 100%, which is unnecessary. There are so many pixels in the Nikon medium-format scans (about 90 megapixels in 6x7 and 55 megapixels in 6x4.5) that this makes up for it. I find that, after cleaning-up and sharpening both scans and digital-camera files, the scan on-screen at about 60% looks roughly comparable to a typical digital-camera file on-screen at 100%. If you're looking at your high-res Nikon 4000 scans at 100% on-screen, you're asking too much of them. Clean them up and sharpen them and view them at say 50% and they should look good.
- Regarding cleanup, I use GEM (built into the Nikon scanner firmware) and/or NoiseNinja (Photoshop Elements plugin) for grain management. Elements' built-in Reduce Noise filter is also sometimes helpful for light grain cleanup; for more pronounced grain, the other tools are needed. I find NoiseNinja is more forgiving at maintaining detail than the scanner's built-in GEM, and more flexible too since it integrates with my editor. I usually combine NoiseNinja with selections to focus more aggressive cleanup on skies and less aggressive cleanup (or none at all) on more detailed areas. Anyway, some grain reduction is part of my cleanup of almost every scan.
- As for color and density, the Nikon 9000 gives me everything I need, but flatter and more tonally-compressed than on slide. I've heard this is a common behavior of most high-end scanners -- tones and colors are compressed to make space for a wider range, or something like that. In any case, I find it easily restorable through levels, curves, and saturation adjustments. The colors and lighting are much more easily correctable/restorable to my liking when scanned from Velvia on the 9000, than when captured digitally (I like Velvia's saturated color palette, contrast, and limited dynamic range).
- As for sharpening, I find the scans need more sharpening than digitally-captured files. I just use Elements' built-in Unsharp Mask for this. The amount and size vary based on output but for good on-screen appearance at say 24 inches wide (at 96 DPI on-screen) I find 200% and 0.5px usually looks pretty good.
- When all is said and done, my cleaned-up and sharpened 6x4.5 scans seem to me like they would be comparable to slightly under 20-megapixel digital camera files. (Hard to tell as I don't own such a camera; I'm estimating after comparing crops with the smaller digital captures I do have.) Scaling down to 35mm, this would suggest your 35mm scans should give quality somewhere in between the D70 and D200 you're used to. So that's what you should be targeting as realistic.
Hope this helps.
PS. I just started learning this a few months ago. There is definitely a learning curve to scanning and post-processing - similar in degree to what I remember when learning the basics of photography (F-stops, DOF, etc). I'm sure I still have much more to learn, but overall the experience has been positive.
Posted by Robert Bunch on February 18, 2010 at 12:16 AM
Scott,
Thanks alot for this information. I guess comparing the scanned slide files with the files directly from my digital cameras is kind of like comparing apples to oranges. Looking at those scanned slide files on the computer was not very encouraging but now that I have a better understanding of the process thanks to you and Mel I'll probably go ahead and buy a scanner and get started on all those slides and negs. I'm glad to know good results can be achieved if you know what you are doing.
Discussion
5 repliesSo,is it just not possible to get as good a quality files from scans from slides and negs as you can from digital camera files or is something else wrong here.
I have a lot of slides and negs I would like to scan and I have been thinking about buying a high quality scanner but with my experience so far I am not sure that it worth it.
Any enlightenment you can give me will be appreciated.
It is absolutely possible to get great files from film scans, but don't assume it is easy. Scanning is a skillset completely different than raw processing. But when it is done well, you'll have a great 14-16 bit file to start with.
Slides are in my opinion more difficult to get a good scan. The dynamic range tests the capability of the scanner more than negative film. Its hard to get clear shadow details and keep highlights. In general they seem more difficult to get a scan that looks just like the slide on a table and part of the "problem" is that you can look at the slide on the light table and decide that it doesn't match. I've also seen some convincing discussions that point to slides being less sharp than negative for one reason or another. I've seen some of this in my own scans. IT8 scan targets can automate color correction in slides and are used to calibrate your scanner against a known target. But I think this could also neutralize some of the nature of a film in favor of a particular neutral color profile.
Negatives are easier to scan because the range fits easily into the scanner's ability, but more difficult because the density curves for the three channels do not line up and they are more open to interpretation because you cannot directly see what they "should" look like when reversed.
To get the best files from scans I think you'll need to learn some photoshop tools that you don't usually need to use for digital capture.
I usually find color issues in my scans in the neutrals and shadows. The scanner may shift the shadows to red or green and I need to correct that out (happens alot).
The first tool I would recommend you learn is selective color's white, neutral and black controls. Inside each "color" you'll find a control slider for cyan, magenta, yellow and black. This is an important skill for scanning and can be applied both in photoshop and the scanning software. Once you've worked the neutrals, you may need to adjust a particular color. The transmitted colors Red, Green and Blue are paired with the reflective colors Cyan, Magenta and Yellow. This principle applies to most color editing.
Adding cyan reduces red. Reducing cyan adds red.
Adding magenta reduces green.
Adding yellow reduces blue.
Adding black to midtones or white can increase color saturation. Adding black to black = darker shadows. Subtracting black from white clips highlights.
You can take this same knowledge to curves and have a different set of controls.
Curves are RGB+Black driven. If you go into the red curve and pull down red near the center, you're adding cyan uniformly to the image. Pull up red and you're subtracting cyan. Small changes here go a long way.
The next thing I've found in working with film files versus digital is that the film is going to have grain. It doesn't look bad printed (It can actually enhance enlargements), but it can appear a bit harsh on screen. Smart sharpen makes a mess of film grain. Use unsharp masks instead with the threshold at 1 or 2 and you can sharpen the image without sharpening the grain so much.
Mel-
Thanks for the detailed and very informative discussion. I can see it is not as simple as I thought and I have much to learn. I'm glad that some of the things I experienced are borne out by your experience such as the difficulty getting good colors and the loss of quality or graininess in slide scanned files and it is good to know that it is possible to get good scans if one knows what they are doing.
May I ask what kind of scanner you use?
Thanks again,
Robert
- At 4000 SPI (the Nikon's resolution) and even when sharpened, my scan files are soft when displayed on-screen at 100% -- softer than digital camera files I've compared with at 100%. They are also much noisier due to the film grain. This is all because a high-resolution scan is pushing the boundaries of what is actually caught on film, I think; that's just the way it is. But that's comparing scanned pixels at 100% to digital-capture pixels at 100%, which is unnecessary. There are so many pixels in the Nikon medium-format scans (about 90 megapixels in 6x7 and 55 megapixels in 6x4.5) that this makes up for it. I find that, after cleaning-up and sharpening both scans and digital-camera files, the scan on-screen at about 60% looks roughly comparable to a typical digital-camera file on-screen at 100%. If you're looking at your high-res Nikon 4000 scans at 100% on-screen, you're asking too much of them. Clean them up and sharpen them and view them at say 50% and they should look good.
- Regarding cleanup, I use GEM (built into the Nikon scanner firmware) and/or NoiseNinja (Photoshop Elements plugin) for grain management. Elements' built-in Reduce Noise filter is also sometimes helpful for light grain cleanup; for more pronounced grain, the other tools are needed. I find NoiseNinja is more forgiving at maintaining detail than the scanner's built-in GEM, and more flexible too since it integrates with my editor. I usually combine NoiseNinja with selections to focus more aggressive cleanup on skies and less aggressive cleanup (or none at all) on more detailed areas. Anyway, some grain reduction is part of my cleanup of almost every scan.
- As for color and density, the Nikon 9000 gives me everything I need, but flatter and more tonally-compressed than on slide. I've heard this is a common behavior of most high-end scanners -- tones and colors are compressed to make space for a wider range, or something like that. In any case, I find it easily restorable through levels, curves, and saturation adjustments. The colors and lighting are much more easily correctable/restorable to my liking when scanned from Velvia on the 9000, than when captured digitally (I like Velvia's saturated color palette, contrast, and limited dynamic range).
- As for sharpening, I find the scans need more sharpening than digitally-captured files. I just use Elements' built-in Unsharp Mask for this. The amount and size vary based on output but for good on-screen appearance at say 24 inches wide (at 96 DPI on-screen) I find 200% and 0.5px usually looks pretty good.
- When all is said and done, my cleaned-up and sharpened 6x4.5 scans seem to me like they would be comparable to slightly under 20-megapixel digital camera files. (Hard to tell as I don't own such a camera; I'm estimating after comparing crops with the smaller digital captures I do have.) Scaling down to 35mm, this would suggest your 35mm scans should give quality somewhere in between the D70 and D200 you're used to. So that's what you should be targeting as realistic.
Hope this helps.
PS. I just started learning this a few months ago. There is definitely a learning curve to scanning and post-processing - similar in degree to what I remember when learning the basics of photography (F-stops, DOF, etc). I'm sure I still have much more to learn, but overall the experience has been positive.
Thanks alot for this information. I guess comparing the scanned slide files with the files directly from my digital cameras is kind of like comparing apples to oranges. Looking at those scanned slide files on the computer was not very encouraging but now that I have a better understanding of the process thanks to you and Mel I'll probably go ahead and buy a scanner and get started on all those slides and negs. I'm glad to know good results can be achieved if you know what you are doing.