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Digital Work Flow

by Roger N. Clark

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In the new digital imaging era, there are many ways to process an image. On this page, I'll discuss the work flow I generally use in processing my images. I must stress that these are my opinions. There are often multiple "correct" ways to process digital image data. and many can produce excellent results.

Digital work flow starts at the point the data are converted from analog to digital. With film this is the step starting at the digital scan. With a digital camera, it is the settings of the digital camera that begin the work flow.

Film. I scan all my film at the full precision of the scanner. Good scanners are at least 12-bits/channel. The output file is 16-bits per channel TIFF images. I do the minimum processing at the time of the scan and save corrections for the photo editor where I have more control. Scan parameters include:

Digital Cameras. I do both jpeg and raw format output. Jpeg is only 8-bit, while raw on many cameras is 12 bit and a few now have 14-bit output. Raw files are converted to 16-bits/channel TIFF files. Critical to the digital work flow is backing up the digital files.

Archive the Original Image Files

It is very important to archive all original image files without any modification, whether they be film scans, jpegs from a digital camera, or raw files from a digital camera. You will see below that I save copies of the original in directories I call "orig." I never modify the original image files. I only modify copies of those files, and I never use the same name in order to prevent any version from copying over a different version. The reason for archiving the original images is that in case you want to go back and redo the processing, you can go back to the original file. Maybe your expertise will improve, or maybe a new processing algorithm with be invented that makes the image better. You need that original file to take advantage of these possibilities.

Digital Image File Management

People often ask about image management software. I do not use any. One reason is that I do not want to be locked into a proprietary system that may not be around in a few years. I want to be able to find my images in 1 year, 2 years, 10 years, 30 years, and for my descendants to find them too, without special software.

I could use an emerging technology of embedding keywords into the image itself (called tags) and then using programs that build ascii lists of file names and key words. That would work and be portable and readable far into the future, except for one problem. Some programs I use do not propagate the embedded tags, so the tags would get lost. There is no single software package that does all tasks. For example, photoshop does not do sophisticated sharpening (e.g. Adaptive Richardson-Lucy deconvolution), and software that does ignores some metadata.

So I organize my photos according to subject by using long descriptive file names and using a directory structure that isolates subjects. For example, I may do something like the following.

where the "/" means directory boundary, so colorado.2005 is a directory. The image catalog number, e.g. c12.25.2005 is the month, day and year, and the 4-digit number is the camera's image number. The letter code before the file extension is the processing version. The brown bear image above with b.tif is the final processed image, version b, the b-700.jpg file name means version b with 700 pixels, signifying my web image. The brown bear image with b-16x24LJs.tif is version b scaled to a 16x24 inch print file for a Lightjet Fuji Crystal Archive ICC profile with signature. The "orig" directory holds the original untouched files, whether jpeg, tif, or raw (e.g. .crw).

The above scheme allows me to quickly find any of my tens of thousands of images. Between directory names and subject file names, I can use the operating system's search tools to search key words and find what I need among all images. In January 2006, I have over 144,000 images online on my system. In December 2015 I had 582464 images (it takes my several year old 3.07 GHz I7-950 computer less than 1/4 second to find images). With a few line linux/unix script, I build a simple ascii listing of images anywhere on the system. I can then search that database in a fraction of a second with a one line unix grep command. Example scripts are shown here. These scripts work on linux, macs and can work on windows 10 if you install the linux tools from microsoft: which gives a linux bash shell and common linux commands.

In the photo editor

Backup the Image Data. I make multiple copies of the images I want to archive. I write images to DVD and hard drives. I employ USB/Firewire external hard drives and back up my images to the hard drive. I make a minimum of 2 sets of backups on DVD and hard drives and keep one set off site. This means I have 5 copies of the data: 2 DVDs, 2 offline hard drives, and on the desktop computer. I also have converted my old PC to Linux servers with large disks. I back up images to the servers for more copies, resulting in 3 different media/format types. This ensures against loss due to changing technology and changing formats/file systems.


DN is "Data Number." That is the number in the file for each pixel.

16-bit signed integer: -32768 to +32767

16-bit unsigned integer: 0 to 65535

Photoshop uses signed integers, but the 16-bit tiff is unsigned integer (correctly read by ImagesPlus). Thus, Photoshop has 15-bit precision with 16-bit files.

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First Published 2005.
Last updated November 3, 2016