Digital Photography by Anthony Meadow
The Education Committee will be writing a column in the newsletter to provide you with information about how to learn technologies and tools that will help in IA activities. We’ve got ideas for the first several columns but we’d like to hear from you about what tools and technologies you’d like to learn more about.
We’re starting with an update on digital photography in this first column and point you to some resources to help you learn more about digital photography.
There are still good reasons for using film, such as documenting structures to meet HABS/HAER standards or perhaps you like using a view camera. For most people photography is now digital. Many skills needed for digital photography are exactly the same for film photography, such as the relationship between aperture and exposure time. But there are technical issues and skills that film photographers never had to deal with.
A few decades ago when I was in high school I learned to develop Plus-X black and white film. The memories of the strong smells in the darkroom are still with me, as well as the magic of watching a print emerge from the shiny white paper. Ten years ago I could see that the mediocre digital cameras were the first step towards the future of digital imaging. I quit film cold turkey and bought my first digital camera. I’ve learned a lot on the way and would like to pass along some of the lessons I’ve learned.
File formats: Almost all cameras support the JPEG format for images. It’s certainly convenient – it’s easy to copy images onto your computer, resize them, email them and even print them. But there are some limitations to the JPEG format that are important to understand. JPEG is a lossy format, that is, when your camera created the JPEG file using the raw sensor data it threw away some of the image data. This may not be important if you are taking family snapshots. When you enlarge a portion of the image, adjust the contrast, apply a filter or adjust the white balance more than once there may be artifacts created in the image. These artifacts are a result of the JPEG compression process that throws away information every time the image is saved, quickly reducing the quality of the image.
What’s the alternative to using JPEG? There are other ways in which images can be saved and edited that preserve the maximum amount of information in the image. First, you can use your camera’s raw format such as the Canon CR2 or Nikon NEF format. These files are compressed but in a lossless manner – no information about the image is thrown away when the file is created. There are few image editors that can read and write these proprietary formats though, so you’ll need to convert the image into another format to edit it.
Images can be converted to lossless formats either from the raw camera format or JPEG. The Photoshop format (PSD) and the Tagged Image File format (TIFF) are the best known lossless image formats.
Adobe has been promoting a lossless image alternative called the DNG (Digital Negative) format which is a third alternative that was designed to support editing and long-term archiving of images. DNG is a lossless format that is widely supported by many image editing programs. At this time some camera vendors support DNG as a native format (Leica, Ricoh and Samsung) but other major vendors (Nikon and Canon in particular) do not. One advantage of DNG is that it contains a checksum that can be used to verify the file integrity, a capability that no other image format offers today. You can read more about the DNG format at <http://www.adobe.com/products/dng/index.html>.
Backups and Archives: Film negatives can last over a hundred years if processed properly. How can we ensure that our digital photographs will be preserved for posterity? For a start you’d better backup your image files regularly so that when the hard drive fails in your computer that all of your images don’t disappear. Offsite backups provide another level of insurance.
Metadata: Metadata is information about an image. Your camera automatically creates some metadata about each image including the camera name, shutter speed, aperture, image size and so on. You can add additional metadata to your images such as copyright information and keywords that describe the image including category, project name, people and objects in the image. The location where the image was taken can added to the metadata automatically or manually (this known as geotagging). The purpose of metadata is to make it easy to search for images in whatever ways you – or others – might need to locate them now as well as in the future.
Digital Asset Management (DAM) Systems: As the number of images you take grows into the thousands or tens of thousands it’s easy to lose track of where your images are and which is the current version of a particular image. One image may be used for a project more than once. Digital Asset Management (DAM) systems are software programs that allow you to catalog, process and print images.
There are quite a few DAM programs on the market. Some are intended for individuals and others for organizations. The more popular products used by serious amateur and professional photographers are Adobe Lightroom, Aperture (Apple), Bibble (Bibble Labs), and Expression Media (a Microsoft product recently acquired by Phase One). All of these products are less than $300 for a license.
Although none of these applications can offer all the capabilities of Adobe Photoshop, the twenty-year old standard, they are rapidly increasing in capabilities. And they offer advantages over Photoshop. These DAMs provide parametric image editing. Unlike Photoshop which directly manipulates the image file, a parametric editor like Lightroom captures your edits as a series of operations performed on the image; the original image is not modified at all. Lightroom also allows you to make virtual copies of an image, making it easy to use prepare image for use in different projects.
DAMs, particularly parametric image editors, enable digital photographic workflow that ensures that all of your images are secure, backed up, searchable and editable. It also makes it possible to process an image in different ways and then compare the results. With Photoshop and older image editors you can quickly find yourself with two – or ten – copies of an image. A year later you may have a very difficult time figuring which one is which. This does not happen with parametric editors such as Lightroom that only have a single copy of an image.
We’ve just scratched the surface in this brief look at image file formats, backups, metadata and image editors. There’s a lot to learn about these topics and more. The good news is that we’re not alone in making this transition to digital photography. The American Society of Media Photographers (ASMP) and the Library of Congress have been concerned about this and have organized a large effort to assist professional photographers. They offer a variety of resources for photographers including (seminars given all over the country) and a blog. Their largest resource is an extensive website that provides detailed tutorials, including hours of video. This site explains how to set up and use a digital workflow that works for you. This website can be found at <http://www.dpbestflow.org/> and is worthy of many hours of your time. And did I mention that it is free?
Two excellent books on digital workflows are “The DAM Book” by Peter Krogh (2nd edition, O’Reilly Press, 2009) and “Digital Photography Best Practices and Workflow Handbook” by Patricia Russotti and Richard Anderson (Focal Press, 2009).