Technical Issues — Photographica

apturing the image is just the first step. The images in this site have been captured a few different ways. Most of the images that are scenics were captured on 35mm transparency film using a Nikon N90 camera and one of several lenses. Many of the snapshot images were captured on 35mm print film using a Nikon 35ti camera (the yuppie camera since it's overpriced and sometimes annoying in its features). Some of the black and white portraits were made using a medium format camera. Some of my newest "snapshot" stuff uses a digital camera.
   The method of capture is very important especially if you intend to enlarge and print the images. If my primary purpose was to produce poster quality images the choice would be clear - medium format or larger. Since the production is for the Internet any of the capture methods will produce very fine results. More on that in a sec.
    For web display all the film camera images need to be digitized. There are many ways o do that. If the output were magazine quality print, the choice would be a drum scan. At $75 a pop you better be serious. I've chosen to scan my slides using Kodak PhotoCD. The advantage of this format is you get scans of several image matrices so that you can choose the one best for your output. The prints are scanned using a HP IICX scanner. Consumer quality scanners have become very good in the last three years.

  I recently purchased the Olympus 600L digital camera. This camera has the capability of capturing about 1200X1100 pixels. As you will read in the next paragraph, a 1.4 megapixel image matrix is too much for simple website design (and too little for good printed enlargements).
    Images that are scanned will be displayed on monitors at full resolution. By that I mean that every pixel that is captured will be displayed as exactly one pixel on the display monitor. If I capture a 4 inch image at, let's say, 150 dots per inch, the 100% image resolution on a monitor will be roughly 8 inches, since the typical monitor has about 75 dots per inch. This is important to keep in mind for your web site (or e-mail) images.
    I've done considerable experimentation and I am convinced that if you attempt to capture at a high resolution and then reduce the image size, the resulting image sharpness will be worse than scanning at full resolution (i.e. ~75 dpi). My friend and teacher, thedude.com, agrees on the sharpness front, but is convinced it is better to capture at least 300 dpi and reduce to web size because of other image quality considerations.Certainly if any image manipulation is done in Photoshop, larger files are needed. The controversy swirls.
    When producing for the web you've got to decide how wide to make text and images. The width of this site is not geared to the smallest displays, but if you go too far only power users would be able to view it. The typical display settings on the laptops that most Sterling field personnel have are 800x600 pixels. That is my website target.
    The scanned images are prepared in Adobe Photoshop. The images are compressed, usually in JPEG format. Most images are around 450 pixels wide, but occasionally I'll include a larger image for power users. This is the rub in the digital world. The larger the images, the more the data, the longer the transmission times, the more memory requirements. JPEG is an industry standard compression algorithm. (In the radiology world, Sterling uses a FDA approved wavelet compression algorithm).
    So that's the way the images are captured and prepared for transmission. The speed that they are painted on your screen is dependent primarily on the transmission speed of your modem or network. I said on my home page that I believe the speeds will be increasing for most users by next year. The typical speed right now is 28.8 kilobits per second. At my loft we are networked via T1 lines, which is 1.5 megabits per second, 50 times faster. When you can get wired at this speed, do it. Surfing the Internet will become a pleasurable experience. For example, the images from this site typically load onto a computer with a 28.8 kbs modem in 15 seconds (if the server's slow or you have bad lines it will be even slower). On my computer they load in less than a second.

    One last word on displays. Laptops are great for many things, but not for displaying images. Most don't support more than 256 colors (unless you go to very low resolution), which can result in posterization - contour lines - in the image. If you are viewing images on a monitor, be sure the colors are set to "Millions of colors" (or the equivalent ). [Start-Settings-Control Panel-Display-Settings in Windows 95].