Best practices for scanning slides

February 10, 2013 2:53 PM

My Dad has a collection of nearly 12,000 35mm slides, which I want to digitize. They've been out in the garage for years, and many of them are 30 to 50 years old. I'd like to make them look as good as possible after scanning. Early results are not what I'd like.

I'm familiar with Photoshop, but ironically not for its primary use of photo retouching. Here's some of the scans (unretouched). Most of them look desaturated and color-shifted, but I'd like to know exactly what filters to apply to improve them. I've tried adjusting saturation, hue, and contrast, but I feel like I'm probably missing something.

They don't look so good zoomed... I'm using an Honestech slide scanner at 10 megapixels-- maybe it's not very good? Or do old slides just tend to look like that?

posted by zompist to computers & internet (14 answers total)

There's some basic tips here but in a nutshell you probably need to adjust the colour curves for each channel (R,G,B) separately.
posted by GuyZero at 3:11 PM on February 10

When scanning slides or negatives and looking at "actual pixels", which is tantamount to viewing them at 100% in Photoshop, virtually every flaw in the originals is going to jump out at you, much more so than simply projecting the slides traditionally.

So, you have to realize that your Dad's technique simply may not have perfect on every shot. Given the age of the images, odds are good that some are soft, some have blown out highlights, the original color balance was not optimal on some when they were shot, and so on.

Many (especially those like your first example) will have gunk on them that may or may not be able to blown of with scanned air prior to scanning.

...not to mention the physical deterioration and color shifts that have come with age.

Frankly, the idea of scanning 12,000 slides isn't my idea of a good time; even with a high end scanner with a bulk feeder. At 59, I wouldn't live long enough to optimize each image.

I would suggest that as a first step, you select 10 or so "worst case" slides and send them to Scan Cafe, to get a reasonable idea of what is possible without dedicating the rest of your like to this project.

Also, I have well over half a million negatives and slides from over 35 years as a photographer, and there is absolutely no way, even if I were independently wealthy, that I would deem more than about 20% of my pictures worth preserving for posterity.

Can you edit those 12K images down to something that's actualyl do-able?
posted by imjustsaying at 3:20 PM on February 10 [2 favorites]

Seeing that you're in Chicago, I would suggest that you give Chicago Film Archives a call and see if they can give you any advice. They specialize in motion picture film, but I'd guess that many of the transparency-scanning / color reproduction issues in film scanning also apply to scanning slide film. (Slides really are the neglected siblings of home movies - the original social media!)

Given that they do a lot of home movie transfers, they may also be able to refer you to someone who you can pay to do that job. 12,000 slides is a lot of slides!

Finally, I want to reassure you that slide scans can definitely look better than what you're getting. (Sadly, aside from the CFA tip I don't have any specific advice for how to accomplish that - sorry!)
posted by bubukaba at 3:22 PM on February 10

I think the Honestech scanner is no good. Your examples have major noise reduction artifacts and are over-sharpened. You can't fix these problems in Photoshop like you could correct a color shift.

A film scanner has a lens and a digital sensor in it just like a camera. You can't get a good digital camera for $130 so I wouldn't expect to get a good film scanner at that price either. When I worked in a photo lab we used Nikon film scanners in the $3000 range. If you are prepared to digitize even 5% of those slides, you owe it to yourself to get a high quality scanner that will produce output worth your time. Sadly it seems like Nikon isn't making film scanners anymore so I have nothing to recommend.
posted by scose at 3:38 PM on February 10

I was part of a professional project to digitize a collection of >20k slides for a museum. We used a very expensive scanner capable of scanning a few dozen at a time and at high resolution. Cleaning up slides so they looked really nice was a very time consuming, and one-by-one task. As said above, there were lots of scratches, dust, and imperfections on the slides. Some of the film had undergone significant color shifts. Our primary goal was to obtain archival quality rescue scans (before further damage could occur). The intent was to preserve information, not necessarily create publishable quality images. The second round of improvements to really make the images publication quality only occurred on an as-needed basis. The first-order scanning process took about a year and a half, as I recall. And that only included first-order image adjustment and cleaning. It produced passable images that could be shared with the professional community documenting some very important discoveries.

So I would second the advice above to be selective about the slides you choose to scan unless you are independently wealthy or have lots of free time. I would also encourage you to consider two tiers of digitization: those images that deserve a salvage scan and those that deserve more time investment to really clean up. In the first case, research color curves and dark/white points. Your goal for salvage scanning should be to preserve as much information as possible by not clipping color curves and not over-filtering the images. If you do a good job with the first, you have good material, in the hands of those adept at this sort of thing (I am not one) to uncover truly nice images.
posted by Tallguy at 3:42 PM on February 10 [1 favorite]

Okay, I've done some level of bulk scanning, though to relatively good quality scans on a Nikon 5000 ED, a professional-level slide scanner. The most important features were:

• Manual focus. The film plane will vary slightly from slide to slide, so being able to accurately focus on it is essential in my book.
• Digital ICE. This was an infra-red technology which magically got rid of a lot of blemishes.
• Compressed air. Okay, not part of the scanner, but part of the hardware side of things. Carefully cleaning each slide before scanning was very important.

The other very important part of the process is the software used. We were using the excellent SilverFast. It's extremely capable, but not very user-friendly. Despite that, once you got used to it's numerous quirks, you could do extremely high levels of calibration extremely quickly. Whilst that level might not be necessary for you, some level of pre-scan colour calibration was essential for every photo we scanned. Once a scan had been made some colour correction and contrast correction was usually necessary too, but that was on a per-photo basis.

An unfortunate fact is that the colour can degrade, especially if the slides haven't been stored in very good conditions. An archivist will be able to tell you more about that.

In terms of your hardware, the Honestech sounds pretty bad, tbh. Maybe there's a service which will rent out decent-quality scanners like the Nikon. AFAIK, the top-of-the-range is the Kodak HR-500, but that's likely beyond your budget.
posted by Magnakai at 3:50 PM on February 10

I'm doing the same thing with my Father's slide collection. Am currently using a Nikon CoolScan at work but feel bad monopolizing the machine for long stretches. They come out really well and clean up well with standard editing software. I would like to have a machine of my own but from asking around and internet shopping I've found that the ones with the best scanning properties and best resolution, are *way* expensive. Any scoop you guys share with all of us is very welcome.
posted by PJMoore at 3:55 PM on February 10

There's a few sites which document people using a DSLR with a prime (non-zoom) lens on a bellows or macro extention tubes to copy the slides. Some use a flash bounced off a white card to illuminate the slide. While this set up would not allow you to use "digital ice" to help get rid of scratches/dust, it would let you do things fast. If you can get or make a slide stage things would go faster.
posted by anon4now at 4:03 PM on February 10

I was in the same boat last year: in the interest of money and time I took them to costco and surprisingly the quality was not bad at all.
posted by dougiedd at 5:43 PM on February 10 [1 favorite]

Lots of good advice above. Editing the images to a more viable number is a great start.

Photo Emulsion Cleaner (try it first on less important or disposable slides), + compressed air will save hours of digital touch ups.

The ROC (restoration of colors) + Digital ICE in Nikon Coolscan scanners work surprisingly well. They aren't sold new anymore, but it may be possible to find someone who could rent you a unit.

We have a Coolscan LS-9000 here and 15 years worth of negatives we are still scanning. Proper scans take time and we realise we will never be done, so if if you can select the most important images in your first edit this will make the task less frustrating.

Scan in a good enough resolution that you never need to go back to the original.

A good light table + loupe will help you edit more comfortably.

good luck!
posted by ig at 5:55 PM on February 10

I highly recommend ScanCafe as well. If you choose to use them (which I did for 4000 of my family's 30 to 50 year old slides), there are usually 20% discounts you can find on RetailMeNot. ScanCafe does color correction on slides. And you can choose to discard up to half of the scans if you don't want to pay for them.
posted by ShooBoo at 8:45 PM on February 10

In terms of using Photoshop to improve the resulting scans, I've been wanting to find enough free time to warrant buying Digital Restoration From Start To Finish by Ctein for ages. The improvements he makes in faded and damaged old photos are incredible, and I'd love to know how to do that. Sounds like something like that might be useful to you.
posted by fabius at 7:28 AM on February 11

Here is a Photoshop trick which might help:
1) Use the HDR tool in Images-Adjustment to play with the contrast and brightness. Set radius to 1 pixel.
2) Or, apply the unsharp mask under Filters, then play with brightness and contrast
3) Then, go to color balance, and adjus the 9 combinations for each color in each of shadows, midtones and highlights. It helps to have a color wheel handy so you can consciously build color as opposed to making random adjustments.
4) Once you get it close, use Image-Auto Color on it, and (hopefully) perfection! (Here's the trick) If it's not correct, choose the color which is causing the most problem, and go back to color balance, and put a lot of that color in the image. Then, use auto color again, and it will over compensate in that color.
posted by DpsDave at 9:05 AM on February 11

I took the hint that the scanner I had was crappy, and bought a new one. I can't afford the high end ones, but a medium-range one was doable. It's a Plustek Optifilm 8100; plus it comes with scanning software that allows adjustable color correction. The difference is like night and day. I'm getting good results even with the oldest slides (50+ years). It takes a lot of time though.
posted by zompist at 9:54 PM on April 28