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Learning Lab






The Ideal Digital Photographer's Workflow, Part 4
Pages: 1, 2

The one adjustment tool you do want to use is the histogram to set the minimum black point, maximum white point, and (possibly) overall brightness. You should use exactly the same procedure you would use to do this in Photoshop. You’re only doing it in the scanning software in order to scan the maximum dynamic range from the original film image by eliminating the pixels that otherwise would be devoted to completely blocked highlights and shadows. If you’re not familiar with the basic histogram procedure, here’s the drill:



  1. Look for a command, tool, or icon called histogram (also known as levels). If there isn’t one, you can do this in your image editing program. The advantage in doing it in the scanner software is simply that you’ll start your image editing application (Photoshop, etc.) with the best-looking image you can get from the scanner without throwing out any data. Once the histogram palette has opened, it will look like the figure shown immediately below.

    Screenshot.
    Figure 2. A typical histogram palette, showing the sliders for black point (deepest shadow), midtone brightness, and white point (brightest highlight without detail)

  2. If either end of the histogram diagram (the thing that looks like the silhouette of a mountain) touches the baseline before reaching the nearest side of the frame, move the corresponding shadow or highlight slider to that point. If the image still seems too bright or dark overall, drag the midtone slider until you’re reasonably satisfied with the result. However, don’t do this to any extreme degree that might cause clipping. Clipping is what occurs when you’ve over-adjusted the midtone slider to the point where the pixels stack so high in the diagram that they are shown as cut off by the top of the histogram frame. If that has occurred, then you have lost image information. The figure below shows how the histogram dialog will look after the sliders have been properly adjusted.

    Screenshot.
    Figure 3. The histogram palette, showing the proper adjustment for maximum data capture.

Color balance isn’t very important if you’re scanning RAW, because you can correct it visually when you interpret the RAW file later.

It’s usually a good idea to do mild Unsharp Mask sharpening -- just enough to make the image look reasonably professional in respect to sharpness, but leaving room for further sharpening later before any halos or artifacts are created. I will soon do an entire article on sharpening that tells you which sharpening tools you should use at each stage of image editing, and to what degree. Meanwhile, you’ll find quite a bit of information in Digital Photography: Expert Techniques that will at least get you started in the right direction.

Be sure you embed the Adobe RGB color profile in every scanned image. Actually, this is to give you a reasonable amount of interpretative flexibility while conserving your time. Otherwise, you should just pick the widest possible gamma for your color profile and then convert that to whatever profile is most suited to the application used for any specific interpretation of the scan.

7. Open the Files in the Photoshop CS File Browser

If you followed steps 1-6, you have easily, quickly, and successfully converted your film to digital files that contain enough resolution and information to make prints of virtually any size. The first thing you should do is to use the File Browser’s Batch Rename command to rename your files according to the guidelines found in Digital Photography: Expert Techniques and in the second of my workflow articles on the O’Reilly site, "The Ideal Digital Photographer’s Workflow, Part 2."

Once you’ve renamed the files, use the File Browser’s Flag icon to mark all of the files you think you’re likely to want to present immediately. Once you’ve done that, use the Show Flagged command to show only the files you’ve flagged, and then duplicate and rename each of those file by adding “edit” to the end of each file name (see Figure 4, below).

Click for full-size view Figure 4. The Photoshop CS File Browser, showing the flagged and renamed scanned files. (Click for full-size view)

Next, apply the steps recommended in "The Ideal Digital Photographer’s Workflow, Part 2" to all of the images you’ve just duplicated. Note that you haven’t lost any of the data you were so careful to preserve in scanning the original files.

Summary

You have just learned that the most efficient way to scan your images is also the best way to ensure that you’ve preserved as much of the data that was in the original image as possible. The big surprise: as complex as some of today’s scanning software is, the secret to successful scanning is applying the KISS (Keep It Simple, Stupid) principle. That is, aside from the histogram (levels) command, sharpening, and the procedures for removing dust and scratches; you’re much better off (and the procedure is much faster) if you do your more refined image editing in a professional image editor such as Photoshop CS.

Finally, many of you are going to ask, "What are we supposed to do when friends, clients, or buyers want us to scan our film so that they can see our pictures digitally on a contact sheet, in an email, or on a web page?" The answer is simple: scan your image as I’ve recommended and then do the best job you know how to do using Photoshop to make the image as visually exciting as possible. Then use Photoshop or Album -- not your scanning software -- to batch convert and export your files to a directory intended for making your web pages or slide shows. Then use Photoshop or Photoshop Album to automatically make web pages or slide shows from the images in that directory.


In March 2004, O'Reilly & Associates released the Digital Photography: Expert Techniques.