FAQ Topics

What is drum scanning? || What is a RAW scan? || How do I get a scan done? || How big? || RBG or grayscale? || 8 bits or 16 bits? || CD-ROM or DVD-ROM? || What do I get back? || What do I do with it after I've gotten it back? || How do I optimize film for scanning?

What is Drum Scanning?

Drum scanning is a method of digitizing photographic film. The result of a scan is a file that contains a raster image of the film. This file can be edited in a photo editor such as Photoshop and printed using any of dozens of digital printing technologies.

Drum scanners are unique among scanners used to scan photographic film in three important ways:

All of these advantages are easily seen in the final prints. Even prints with as little as 2x enlargement show the results of a good drum scan, while prints with 10x enlargement and even higher can be extraordinarily sharp with smooth tonality and excellent shadow and highlight detail.

The bottom line: drum scanning is the best technology for scanning photographic film.

What is a RAW Scan?

A RAW scan results in a file that is similar to a RAW file from a digital camera except that you don't need a RAW converter to use it. It's a standard TIFF file that is ready for photo editing with a program like Photoshop. It needs to be cropped, cleaned up, color corrected, and in general edited to express your artistic vision. See FAQ topic What Do I Do with It after I've Gotten It Back? below.

How Do I Get a Scan Done?

Easy enough. You use the get quote / place order pages. First, specify the type of scan you want. Then review the results. Modify your specifications and repeat until you get just the scan you want. Finally, fill out and print the order form. Sign the form and send it with your film and a check for the full amount to the address on the printout. If you want different batches of film to be scanned differently, just repeat the process. The shipping fee covers all the scanning in one combined order.

Do make sure to pack the film carefully. Do cut roll film and send only the frames requiring scanning. It has to be cut to be mounted on the drum and it's better for you to cut it than me.

How Big?

Bigger takes more scan time and therefore costs more. Is it worth it?

There are a couple of schools of thought on this. One says you should scan for the print size you expect to use now. Another is to scan for the biggest print size you expect to ever use, and downrez this big master file to the print size you want to use at print time.

I really can't advise on this. Everyone works differently. I will say this though. If over time you scan the same film twice for two different print sizes, you also end up spotting twice. And for color work, color correcting twice.

RBG or Grayscale?

It takes longer to run an RGB scan than a grayscale scan of the same size, so it costs you more. Is it worth it?

A grayscale scan captures all the sharpness and detail from the film along with the vast majority of the luminance detail (the range of tonalities from black to white). What an RGB scan adds to this is hue and saturation information. So an RGB scan is worth it if you need that hue and saturation information; you'll certainly need it for full-color prints.

Color Films

If you intend to make a color print, then clearly you need an RGB scan.

If however you intend is make a B&W print from a color image, it is probably still best to scan it in RGB. The reason for this is there are numerous ways to convert from RGB to grayscale in Photoshop, including plugins for just this purpose. Also, if you want to explore simulating filters in your image editor, as if you had exposed B&W film using a yellow or red filter, you'll need all three channels.

Black and White films

If you use a non-staining developer for your B&W negatives such as D-76 or XTOL, there is little to be gained by scanning the film in RGB. This is because B&W films processed this way have very little hue and almost zero saturation information.

I've tried many different methods of converting to grayscale from RGB scans for these film and developer combinations. It's possible to equal or just barely exceed the image quality from a straight grayscale scan, but it takes painstaking work and the workflow has to be customized for each image. But if you want that final 1%, that's how to get it. As a result of my experiments, I recommend a straight grayscale scan for B&W films processed with non-staining developers. It's what I do for my own film.

If you are using a staining developer such as Pyro or Pyrocat HD, scanning in RGB vs. grayscale is a somewhat more difficult call. The reason for this is the color of the stain and the fact that there is more hue and saturation information available. The stain color can shift the tonalities a bit so there is somewhat more difference between a straight grayscale scan and an RGB to grayscale conversion. With staining developers you might want to go through the effort to scan in RGB and convert to grayscale in Photoshop. It depends on your intent and your workflow.

8 Bits or 16 Bits?

A classic question, this. It takes a bit longer to run a 16-bit scan over an 8-bit scan of the same size. So it costs you more. Is it worth it?

If you make large manipulations and corrections in an image editor like Photoshop, you'll want the extra head room that a 16-bit scan provides. It's easy to get posterization in an 8-bit file with moderate manipulation.

The general rule of thumb is that due to the WYSIWYG nature of transparencies, the file should look substantially like the film. This means that you probably won't be making big changes, so 8 bits will probably be fine.

For negatives, both color and B&W, I highly recommend 16-bit scans. The reason is that most negative scans will be somewhat flat. A typical image-editing workflow usually includes clipping some of the non-relevant data (specular highlights for example), then applying a curve to increase over all contrast. It's not unusual to see some posterization occur with an 8-bit scan at this point.

CD-ROM or DVD ROM?

Your files will come on CD-ROMs or DVD-ROMs, depending on what you specify. Both can be read by either Macs or PCs. The CD-ROMS conform to ISO-9660 and can hold up to about 700 MB.

What Do I Get Back?

You get back your film and at least one CD-ROM or DVD-ROM (depends on file size and your preferences). If possible I'll reuse the packaging that you used in sending the film to me.

The files you get back will be very clean, but they will not be spotless. Let's face it: dust is everywhere. It can get on your film when you are loading film holders, when you are drying it, or as you are slipping it carefully into a sleeve. Loose dust can be removed, but if you dry B&W film in a dusty environment, the emulsion acts like glue and glues the dust to itself. Once embedded, always embedded. And even though I work carefully in a very clean room, it's not a cleanroom, so I can get dust on the film too. This is why dust busting is one of the steps artists usually perform on scan files.

The files you get back will contain some rebate (unexposed film that was under the film rails in the film holder when you made the exposure). I do this to avoid inadvertently cropping any of your image from the scan. You can control this to a large extent. You can tell me that you don't want it, or that you want all of it when you order. I'll try to give you exactly what you want.

Until you are used to them, some full-range scan files may seem to be visually flat. This is done on purpose: these scan files capture the full range of tones on the film. During the editing process, the artist often decides to modify the black and white points for the file and to adjust the tonal relationships to increase or decrease contrast in the print or in just in certain areas of the print. I make a full-range scan to insure that the artist has the maximum amount of image information to work with. I don't want the scan to limit what the artist can do, I want the limit to be the artist's imagination.

The files themselves will be uncompressed TIFF files. Compression of large files is somewhat risky. The LZ-based algorithms used by many compression schemes can be fragile: one flipped bit can render the file unopenable. Compressing the data is not worth the risk.

What Do I Do with It after I've Gotten It Back?

The next step after obtaining a scan file is to prepare the file for printing. The workflow you choose to accomplish this is a personal choice. The important thing is to find a workflow with which you are comfortable. I personally like to crop the image first thing, then apply a light capture sharpening step (in some cases none), then do my dust busting up front. Others will council to save dust busting until last just before output sharpening. Whatever works for you is fine.

In any case, the typical workup for an image file after scanning includes the following, not necessarily in this order:

This is the basic idea. Again, there are numerous workflows, all with their advocates.

How Do I Optimize Film for Scanning?

If you are ever planning on using your film for darkroom printing, then you should optimize your film for darkroom printing. It will scan just fine if you do this. If, on the other hand, you plan to only scan your film, then you can optimize the film to get better scans.

Black and White Negatives

The sharpness and graininess of film is directly related to density. Less dense films scan somewhat more easily than more dense film in my experience, and result in scans that appear sharper and less grainy. This is particularly true of B&W films. The metallic silver in the highlight areas tends to scatter light. This is called the Callier Effect. The effect is to decrease local contrast in the more dense areas of the negative.

When you lower the Dmax of a B&W film, you get three benefits. First, you increase local contrast in the most dense areas by decreasing the Callier Effect. Second, you decrease the amount of graininess of the scan and therefore the final print. Third you increase the potential for a sharper image on film, and therefore a sharper final print.

Now, you can take this too far. If you decrease density too far you lose some of the benefits of large format film. Namely, you compress the tonality of the film and lose some of the richness you get with the extra film area of large format.

So, where is optimum?

For my B&W film I've found that a Zone VIII density of around 1.0 gives excellent results. This would of course be thin enough that it would be difficult to print in the darkroom, but it scans quite well for me.

Color Films

Color films, both negative and transparency, tend to be more dense than their B&W cousin. While the image in modern color films is made of dyes instead of metallic silver, this density of the dyes has its effects. The scanner sees an area of high density in the film as an area of low signal (less light makes it through to the photo detectors). This in turn lowers the signal-to-noise ratio. It is theoretically possible to introduce some noise artifacts into the scan because of high density in the film. On the practical side, however, I haven't seen it yet with my scanner, so I don't see much utility in working to decrease density in color films.

For color negative film, the best optimization you can do is to nail the exposure for the shadows. If there's not enough exposure for the shadows, then they won't record on the film. If they aren't on the film, then the scanner can't read them. So expose for the shadows and let the highlights fall where they may for color negative film. The reason for this is that the C-41 process doesn't lend itself to push and/or pull processing like B&W film processing does. Pull processing C-41 can result in undesirable color casts for example. Since the dye clouds in color film don't generate any Callier Effect, and there is usually no noticeable noise added by the scanner due to the density anyway, there's little reason to try to optimize the film's density.

For color transparency, the best thing you can do is nail the exposure for the highlights. If the highlights blow out so that there's nothing recorded on the film, then the scanner can't read them. So expose for the highlights and let the shadows fall where they may for color transparency film. If the drum scanner generates any noise due to the highly dense shadow areas of the film, it will be in the shadows where it will be very difficult to see.