From mid-October through November 2005, approximately 6200 photographs that were available for sale at the store DV33 Vintage Photographs were examined. Of those, 76 that were thought to be the most interesting were selected and purchased. Each was used to create one two-part image.

The photos were scanned using an HP ScanJet 4200C scanner and the software program HP PrecisionScan LT Version 2.0.3cu. The resolution used for a given photo was the maximum for which the resulting JPEG image would be no wider than 300 pixels and no taller than 320 pixels.^* In most cases, the output type was set automatically by the program to either "Black and White Photograph" or "Best Color Photograph (16.7 million colors)", depending upon the photo. If instead, the software selected "Black and White Drawing" or "Color Drawing", this was changed manually to "Black and White Photograph" or "Best Color Photograph", respectively. The images were saved as JPEG files. To obtain maximum quality, the lowest possible degree of compression was used.

After all photos had been scanned, the two-part images were created, one per day, from February 11 through April 27, 2006. These were made in the order in which the photos had been selected. In what follows, the procedure used to create the two-part image for a given photo is described.

First, the software program LView Pro 1.B2/386/16-bit for Windows 3.1 was used to crop the photo border from the image generated by PrecisionScan LT. The cropped image was saved as a JPEG file. To produce high quality images, a maximal "compression quality" setting of 95 was used for minimal compression.

Next, some number of yellow lines were drawn on the cropped image using the "Single Line" tool of the software program Ultimate Paint Version 1.91f by Megalux. This tool automatically draws a line from one user-specified point to another. The resulting image was saved as a GIF file. Here, the GIF format was chosen (over JPEG) to ensure that the color of the lines would not be altered through the process of saving the image to a file.

A governing factor in creating line drawings was the degree to which the resulting two-part images were thought to be interesting; images that were thought to be the most interesting were selected over others. For a list of factors that affected the degree to which a two-part image was thought to be interesting, see Considering a Two-Part Image: A Factorial Poem. (Note: All decisions concerning lines were made using a screen resolution of 640 by 480 pixels on a 17-inch CRT monitor attached to a computer running Windows XP Home Edition 2002 Service Pack 2. Final decisions were made while viewing the two-part image in the "full screen" mode of LView Pro for which the image is centered on the display against a black background.)

Finally, a two-part image was constructed from the photo and line drawing. To this end, the cropped photo image was opened in LView Pro. The width of the image was doubled (plus 6 pixels for space between the line drawing and photo) and the photo was moved to the right. To accomplish this, the following sequence of operations was performed on the cropped image: flip horizontally, redimension to be twice the original width plus 6 pixels, and flip horizontally, again. (Note: In LView Pro, when the size of an image is increased by using the "redimension" operation, an exact copy of the original image is placed in the top left corner of the enlarged image. The remainder of the enlarged image is filled automatically with the current background color, which in this case was black.)

A second instance of LView Pro was executed to open the GIF file containing the yellow line drawing superimposed on the photo. The following steps were used to change the color of all pixels, except the yellow lines, to black: select "Color Depth" from the "Retouch" menu; on the "Color Depth" dialog box, select "Palette image", "Windows palette (16 colors)", and deselect "Enable Floyd-Steinberg Dithering"; select "Gamma Correction" from the "Retouch" menu; set the scroll bar for each color on the "Gamma Correction" dialog box to -99; select "Palette Entry" from the "Retouch" menu; and change the color of the white palette entry to black. The color of the yellow lines was changed to the average color of the cropped photo.^† To complete the two-part image, the line drawing was copied and pasted to the left of the photo in the other instance of LView Pro.^‡

The two-part image was copied and pasted into Microsoft Paint 5.1. Then, it was saved as a PNG file. (Note: Microsoft Paint was used because LView Pro 1.B2/386/16-bit for Windows 3.1 cannot create PNG files.) The PNG format was chosen (over JPEG and GIF) to ensure that the image would not be altered through the process of saving it to a file. Finally, the size of the PNG file was reduced using the software program OptiPNG 0.5.2 by Cosmin Truta.

A random 2-digit number was assigned to each of the 76 two-part images. To generate a number, a 10-sided die (with faces labeled 0 through 9) was rolled twice. The first roll was for the most-significant digit; the second was for the least-significant digit. In some cases, the same number was assigned to more than one image. For such images, the 10-sided die was rolled one more time. The resulting digit was appended as a decimal digit after the image's 2-digit number. Additional decimal digits were generated and appended as needed until a unique number was assigned to each image. The images were sorted in numerical order using the randomly generated numbers. Then, they were numbered in that order from 1 through 76.

An HTML page was created for each two-part image. The images were placed on a black background at the top of the pages. The color of the bottom section of the pages was set to the average of the colors used for line drawings.

* The JPEG image size for photos was constrained to ensure that two-part images would be entirely visible (without scrolling) in a typical Web browser window at a screen resolution of 640 by 480 pixels.

† The software program Color Average Calculator by VDT software was used to determine the average color of the cropped photo image.

‡ Line drawings were placed to the left of photos rather than to the right because this arrangement was thought to be more interesting. Perhaps the following two factors play a role here: (1) information that is in the right visual field is routed to the left brain while that which is in the left field goes to the right brain and (2) there is reason to believe that the left and right hemispheres have different abilities (The Nature of Human Consciousness: A Book of Readings, ed. Robert E. Ornstein [New York: Viking Press, 1974]).