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Film Scanning with a Flatbed (Epson 4870) |
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Introduction In recent years the best flatbed scanners have advanced to where they are competing with high-end dedicated film scanners for quality of results. Flatbeds have these characteristics in their favor:
Principle drawbacks:
So, are flatbeds good enough? If you Google for reviews you will find the following ... A good flatbed such as the Epson 4870 leaves little to be desired with medium format film. On 35 mm, the dedicated scanners win the contest although it is inconclusive whether or not this higher quality is visible in a large print. The comparisons you find are of the "pixel-peeping" variety involving intense magnification of test images. The dedicated film scanners offer slightly more detail and a somewhat superior DMax range meaning they should be able recover more shadow detail from a film image having high dynamic range. In practice there is, again, some doubt this leads to a visibly better result when it comes to final presentation. In short, a good flatbed is just about as good as a high-end dedicated high-end film scanner when it comes to image quality and may be everything you need when it comes to dealing with your film archive. When choosing a scanner look for:
Nothing else matters a whole lot. Check the online reviews for user experiences regarding effectiveness of film holders, reliability, etc. Why Scan? Because film is not forever. In my experience, well-cared for transparencies deteriorate visibly after about 30 years. In particular, there is:
By scanning film images you ensure survival of your archive. Digital may not be forever either but it is pretty certain that CDs and DVDs (which is how you will store your archive) have a longer lifespan than film - 100 years at least and probably much longer. No one really knows just how long but you can always play it safe by periodically copying all your digital media - let's say, every 25 years which ought to be very safe indeed. If any slight deterioration of the bits has occurred, this will be perfectly corrected through the digital regeneration process provided by the recording technology's error correcting and redundancy provisions. There is no equivalent in analog information storage systems. What they lose is gone forever. Don't believe what you occasionally read by so-called "experts" claiming that evolving technology will obsolete your DVDs and CDs, making them unreadable in some distant future. These standards are heavily entrenched everywhere from seismic exploration archives to medical imaging databases to government and business record keeping. You are in good company with influential users highly dependent on CD/DVD data storage. 200 years from now your disks will be perfectly readable. Eventually non-rotating storage will take over but it will be easy to convert and you can bet services will spring up to do the job for you at a low cost. Relax. Another reason to scan is that you may find you still enjoy using your film equipment but want to enhance the images digitally and/or print them yourself without using the chemical darkroom. Digital advances notwithstanding, film remains an excellent imaging medium and for formats larger than 35 mm it is unbeatable. Even 35 mm can deliver excellent results although I find not nearly so easily as with top-line digital cameras. The principle drawback to using images made from scanned film is that they include not only defects resulting from the digital process but from the film too. For example, the images will have some digital noise as well as film grain. In general this is not a serious drawback and there are effective remedies. Any good scanner these days will incorporate "Digital ICE" or something equivalent to remove scratches and dust but you should appreciate just the same that scanned images are not a perfect replica of the film image. You may have to deal with that in processing. In my experience it is better to have images digitally rendered to begin with, by using a high quality digital camera, and eliminate the "middle man" - film. This applies mainly to small formats such as 35 mm. At today's state of the art medium format film, at its best, is superior 35 mm film and most digital formats whether scanned or traditionally prepared for presentation. Commercial or DIY? You can have your film scanned commercially and this is doubtless the best way for dealing with large numbers of images. Furthermore, most film developers these days offer simultaneous scanning although the standard option will be a lower quality JPEG. High quality scanning is available from a vast number of suppliers and probably your preferred film processor as well - at a price. A quick check of the Internet suggests that 4000 dpi/16 bits per channel scanning will cost you about $1 per 35 mm image, storage media and Digital ICE included. Doing it yourself can make sense - for the greater control available and lower cost. The typical amateur scanner is quite slow, however. With Digital ICE engaged the Epson 4870 will take almost 15 minutes to scan a 35 mm transparency at full resolution and bit depth. Obviously, you won't want to scan everything (unless you go the commercial route where the equipment is much faster) - a 36 frame roll of film would take 9 hours on the Epson. Some triage is usually necessary as a first step wherein you are merciless regarding duds and mediocre shots. The rest of this document explores some findings obtained using the Epson 4870. This unit has been replaced by new models but if the reviews are reliable, improvements are subtle. Most of these observations should prove useful when considering the latest equipment, including other makes and models.
Film Preparation and Positioning Owing to the great magnification required to reach a reasonable presentation size, 35 mm film images are notorious for revealing defects such as specks of dirt and scratches. Medium format is much more forgiving but even so, you will want to be careful.
Dust, dirt and scratches Many dust specks can be removed using compressed air. Brushes are useful for more stubborn stuff but sometimes do more harm than good. Being a good insulator, film is terrible for acquiring a static charge which attracts and holds dirt. I find indispensible one of those piezo-electric hand-powered ionizer guns formerly sold to de-pop vinyl LP recordings. This produces a stream of ions when squeezed and your film is instantly neutralized. Dirt falls off all by itself. If you can find one of these units it is one of the most useful photo gadgets you will ever have. Why not forget about film cleaning and rely on Digital ICE? It only makes sense to exercise some care. ICE is wonderful but throw it too much gunk and it may start leaving artifacts you must clean up manually. Nothing is fool-proof.
Positioning Reviews of scanners usually get into the matter of what is the optimum height of the film above the glass and how much does curvature of the film matter. I did some tests with an engraved metal scale set up as a shallow ramp over the scanner glass. You have all seen that sort of thing in the reviews. I could not see any significant variation in scanning quality from almost touching the glass to an altitude well above where the carrier would position the film. In a word, relax. There is a generous range of sharp focus and even some film curvature does not take you outside that range. The only position I found somewhat compromised was with the film in actual contact with the glass. This produced a faint haze in images so there must be some effect such as flare exacerbated by the film and glass surfaces being so close together. Intimate contact also encourages the appearance of "Newton's rings" - a contour-like patterning of the image resulting from mutual interference by light waves reflecting from the closely spaced surfaces. If you really want to pixel peep where the individual pixels become visible at highest scanning density, you will find a very, very slight advantage at the height the film carrier positions your material if the latter is perfectly flat. Quite shocking, really, to discover that Epson know what they are doing. Speaking of film carriers, Epson's are excellent, clamping the film along the edges so it lies substantially flat. Be sure the emulsion side of the film faces downwards. This helps avoid imaging of defects in the non-emulsion side because they are now partially masked by the image itself.
Cover Plates If you are the fanatical type or in the very unlikely event your film is severely buckled, a cover plate works well. Cut a piece of hard, colorless clear plastic to fit just inside the opening of the film carrier where the transparency lies. The weight of this cover plate will partially flatten the film (or you could tape it down. Some ingenuity will come in handy). To avoid Newton's rings, abrade the surface of the plastic in contact with the film. An electric toothbrush charged with toothpaste is perfect for this and it will take about 5 minutes to get a nice, even haze on the plastic. Get this as uniform as possible by moving the brush a lot and in a random pattern. Even better is a glass plate because it is much heavier. This will require you know how to cut glass and have a cutter. Be sure to wear goggles when cutting and possibly gloves - there is significant risk of splintering. Smooth the edges of the cut piece with an old file or sandpaper. If you don't you are sure to draw blood before long. A framing shop can do all this for you for a few dollars. Abrading the glass surface takes much longer than with plastic and it helps to use a household cleanser such as "Old Dutch" (but don't use this on your teeth). With plastic or glass you do not need intense abrasion of the surface - a fine haze will do the job. With 99% of my material a cover plate has never proved necessary. It's useful only in extreme situations. When using a plate, I have never been able to detect the abraded surface being imaged. The scratches resulting from fine abrasive are simply too small, too close together and too shallow to be resolved (if you did this right). There are probably commercial diffusion plates available and it should be possible to cut one of these to size. Needless to say, a cover plate should be thin enough it does not contact the glass underside of the scanner hood.
Scanner Setup Strategy As with most things in life there are a number of ways of getting to a desired objective. A good deal of other advice on the web suggests scanning to your desired presentation size at an adequate sampling density (let's say 300 dpi = 150 line pairs per inch which at presentation size is about all the eye can resolve). The problem with this approach is that it commits your scan to a certain size and resolution and the choices made by the writers of the scanner utility software. After that you are stuck with what you got. Furthermore, the scanner software invites you to invoke its various imaging processing facilities such as color balance adjustment and defect removal. These processes are liable to prove irreversible, should you wish to do something else at a later time. After much experimentation leading to great results my approach is this - treat the scanner as just another digital camera (which it is) and the film image as just another sensor (which it is). You have already invested significant money in imaging software such as PhotoShop, Paintshop Pro, SilkyPix, etc. This is the place to do most, if not all image processing. Of course, if your main interest is in producing small snapshots for the web or a photo album, there is little point in taking great pains on behalf of image quality. The automatic settings of the scanner will do an adequate job besides saving you a lot of time and you might as well just pump out JPEGs too. You can save even more time by not reading the rest of this and by having your scans done commercially.
Scanner Settings This discussion assumes you are familiar with scanner software settings and know where to find them. The following are my settings, done in "Professional" mode:
You are now ready to scan (but do a preview first to select scanning area). The whole point of these settings is to produce the scanned equivalent of a digital camera RAW or NEF file with as little contribution from the scanner software as possible. If you let the scanner software do anything at all to this original image it will be irreversible in future. About the only things we are letting the scanner do is:
Everything else we do on the PC where we have much better facilities. Furthermore, if we mess up there, we still have that original, unprocessed scanner image to go back to which will not be the case if we let the scanner software muck with it. This is not to disparage scanner software entirely. In fact, it is pretty good but one objective of this site is to encourage craftsmanship. You will always get better results by exercising as much control as possible yourself.
Processing You are mostly on your own here and probably know what to do already. Your existingl workflow for camera images should do the job. Attend to the usual requirements, in more or less the following order:
Some iteration is often required for best results. There is some variance in advice from experts concerning the order of processing steps. In general though, leave sharpening toward the end. If you use a stand-alone printing package like QImage do not re-size/re-sample. Leave this to the package when you drag the image into the printing template. If you scanned at the recommended high resolution there is an excellent chance film grain will be visible at print size. Your noise reduction software can almost certainly deal with this but beware over-kill. It is better to leave some grain than to destroy fine detail in an effort to remove all of the former. Silverfast and Other Scanner Add-on Software I used Silverfast for awhile and could find no advantage. This product (and possibly others like it) incorporate custom algorithms to automatically massage the output from a particular scanner for best color balance, contrast, etc. That is, SF functions as an improved replacement for the scanner software. This seems to me of considerable usefulness to someone like a "pro" photographer doing high volumes of scans and not wanting to do any post-processing himself. I discovered I could mimic whatever Silverfast does with a script in Paintshop or a customized Development Parameter suite in Silkypix with the advantage I still had my original scanned image to go back to. To each his own. Silverfast has a great reputation and there are many who love it. It may be just the ticket for you but it's not for me.
Conclusion This article is based on experience. I routinely obtain excellent scans from both 35 mm and medium format film. After processing they are extremely sharp and have all the technical merit I look for in a properly taken photograph (providing the original material was good). The trick for me is restrict the scanner to delivering the raw image (TIFF format), reserving most, if not all processing to the much more sophisticated software on the computer.
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