The first step was finding old pictures of familiar sites. Most of the images came from the large and well-organized collection of the Oregon Historical Society. Independent photographic archivist Thomas Robinson provided several images, as did Portland historian Kim MacColl.
After choosing suitable images, I went out and tried to take the same picture. I experimented with a 4 x 5 view camera but all the pictures I used were taken with my 35mm camera. In some cases, I took multiple exposures from the same spot at different angles, then stitched together the images into a single semi-panoramic image on the computer.
Most of the time, it wasn't too difficult to match the historic picture, although several times I had to return to the site and take another group of pictures after seeing the first set would not match. The bicycle was an enourmous aid in this process. I found being able to wheel right up to a site much easier and less time-consuming than trying to find a parking place, and then lugging the cameras and tripod from the truck to the site.
The historic photos were scanned on a laser scanner at a publishing service bureau, and the contemporary photos were scanned using the Kodak Photo-CD process at Lazerquick and Wy'east Color.
With scans in hand, I began combining the photos using Adobe Photoshop software on the Macintosh computer. Some of this work was done on my now obsolete C610 but most was done using the high-performance Macintosh workstations at the Pacific Northwest College of Art.
Photoshop is a wonderful program for combining images. In fact, I like it so much I wrote a book about it called Photoshop Collage Techniques. Take a look at it at any major bookstore, or you can order from Amazon through me and get a 20% discount (I get a bonus too, but only if you follow one ot the links from here.)
After combining the old and new photos, I had Citizen's Photo create a 35mm or 4 x 5 negative of the digital image using their film recorder. I then used these negatives to create traditional limited-edition photographic prints.
To create the interactive movies used in this web site, I first collected all the data (e.g. title, location, image source) about the various images into a Filemaker Pro database. Then I exported three versions of each image from Photoshop: The old image, the collage, and the new image. This was easy to do by telling Photoshop to reveal or hide specific 'layers' from the collage.
The three images were imported into the multimedia authoring program Macromedia Director. I created a script that told Director to blend the images according to the position of the slider. Director then created a Shockwave movie which allowes people to manipulate the images using their web browser.
But I didn't have to repeat all this effor for each image. I only did it once, then had Filemaker Pro repeat the process for each of the images. Filemaker sent instructions for each movie to Director using Applescript, and also generated the html code for each image.