Transfer process
A cartridge of ink is attached to a print head with up to hundreds of nozzles, each thinner than a human hair. The number of nozzles and the size of each determines the printer's resolution. As the print head moves across the paper, a digital signal from the computer tells each nozzle when to propel a drop of ink onto the paper. On some printers, this is done with mechanical vibrations. Piezoelectric crystals change shape when a voltage is applied to them. As they do so, they force ink through...
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All Rights Reserved Click for Contact and Legal In forma lion Tli-T n'i-tiiihr CqLd FlcJn-n j lr,' Diicufcii-Mfl FtirkJrtit S Nruv Original Etabk* Oh Digilal Phola l-Bphy And Many, Many, FiiU'c Titles on D gte Photography Book Contents Previous Page Next Page A Short Course in Digital Photography
Scanning an Image for Printing at a Specified Size
There are times when you know what size you want a print to be and need to calculate backwards to what size the image file should be. For most purposes, you can expect to get photorealistic quality with a print having about 300 dpi. This means, a 4 x 6 print needs an image file of 1200 x 1800, and an 8 x 10 print needs one 2400 x 3000. You can stretch or shrink images you've imported into programs such as PageMaker and QuarkXPress. Because the number of pixels in the image don't change, the...
Image Sensors
Just as in a traditional camera, light enters a digital camera through a lens controlled by a shutter. Digital cameras have one of three types of electronic shutters that control the exposure Electronically shuttered sensors use the image sensor itself to set the exposure time. A timing circuit tells it when to start and stop the exposure Electromechanical shutters are mechanical devices that are controlled electronically. Electro-optical shutters are electronically driven devices in front of...
Editing Formats
When editing photos, you usually preserve the original file and save the one on which you're working in an uncompressed or lossless format. One such format, TIFF has already been discussed. Here is a brief discussion of some other leading file formats. None of these formats are compressed, so their file sizes are quite large compared to JPEG images. When working on images in Photoshop, there are many features, such as layers, that serve a purpose only when editing. For this reason, Photoshop...
Image Sensors and Colors
When photography was first invented, it could only record black & white images. The search for color was a long and arduous process, and a lot of hand coloring went on in the interim (causing one author to comment so you have to know how to paint after all ). One major breakthrough was James Clerk Maxwell's 1860 discovery that color photographs could be formed using red, blue, and green filters. He had the photographer, Thomas Sutton, photograph a tartan ribbon three times, each time with a...
Screen Resolution and Image Size
On any given monitor, changing screen resolution changes the size of displayed objects such as icons, text, buttons, and images. As the resolution increases, object sizes decrease but they do appear sharper. Take a look here at the same image displayed at three different resolutions 640 x 480, 600 x 800, and 1024 x 768. 640 x 480. At this resolution, an image in Photoshop fills the screen. 800 x 600. When the screen resolution is increased, the image gets smaller. 1024 x 768. When the...
Photography Web Sites
There are thousands of Web sites dealing with photography. They include photographers, galleries, museums, and companies. Since the list is ever changing and always expanding, the best approach is to use a search engine such as Yahoo or Alta Vista to find what you want. ALL-IN-ONE Search Page is a compilation of various forms-based search tools found on the Internet. Alta Vista is one of the most powerful search engines. HotBot is one of the latest and greatest. Yahoo is one of the first Web...
Introduction
All great images, digital or otherwise, start by capturing a great photo and capturing great photos requires an understanding of your camera. It's these aspects of digital photography that this book is all about. - To browse through chapters, click the Previous Topic or Next Topic button on the navigation bar. - To jump between chapters openers, click the Previous Chapter or Next Chapter button on the navigation bar. - To display the book's table of contents, click the Book Contents button on...
CCD And CMOS Image Sensors
Until recently, CCDs were the only image sensors used in digital cameras. They have been well developed through their use in astronomical telescopes, scanners, and video camcorders. However, there is a new challenger on the horizon, the CMOS image sensor that promises to eventually become the image sensor of choice in a large segment of the market. Charge-coupled devices (CCDs) capture light on the small photosites on their surface and get their name from the way that charge is read after an...
How are Digital Photos Used
Most of us take lots of photos and then chuck them in a drawer. If we care enough about some, we may even put them in an album. The problem is, we rarely share them with others and after awhile forget a lot about the circumstances under which we took them. Digital images change all of that. They are easy to insert into documents or Web pages along with captions or text. This makes it easy to create journals for personal memories or to share with others. You can post them on the Web for anyone...
Incrementing the Images
When you take a series of images, you nave to be sure they cover the entire 360-degrees and overlap by 50 . You can guess-timate this but it helps to have a tripod head designed for the task. Some come with degree marks to guide you, but better ones come with detents so the camera snaps into place at the exact position. The Kaidan Landscape Bracket (QPLB-1) uses detent discs with click-stops to let you easily rotate the camera the correct increments. Image courtesy of Kaidan. A wide angle lens...
Mailing lists
Mailing Lists use e-mail to keep groups informed on topics or events such as when a particular Web site has been updated. A mailing list is managed by a program called a listserver, the most popular being Majordomo, Listproc, and Listserv. A good place to locate mailing lists is Liszt, the mailing list directory. While some mailing lists accept mail from anyone, most are set up to only accept mail from subscribers. There are also moderated lists and mail can be obtained in digest form or...
GIFs GIF
GIF (Graphics Interchange Format) format images, pronounced jiff, are widely used on the Web but mostly for line art, not for photographic images. This format stores up to 256 colors from an image in a table called a palette. Since images have millions of colors, a program such as Photoshop selects the best ones to represent the whole when you save the image in this format. When displayed, each pixel in the image is then displayed as one of the colors from the table, much like painting by...
Image Sensors Capturing the Photograph
The Development of the CCD Image Sensors and Pixels Image Size Resolution of Digital Devices Image Sensors Image Sensors and Colors Area Array and Linear Sensors CCD and CMOS Image Sensors Unlike traditional cameras that use film to capture and store an image, digital cameras use a solid-state device called an image sensor. These fingernail-sized silicon chips contain millions of photosensitive diodes called photosites. In the brief flickering instant that the shutter is open, each photosite...
Panoramic Stitching Software
After you shoot a series of images for a panorama, you then have to digitize them if you didn't use a digital camera to capture them. Once in a digital format, you use software to stitch the digital images together into a seamless view. Here's how you do it with Rounabout Logic's Nodestar program. You first acquire and arrange your Nodester then calculates the frame source images in the Framespanel overlap in the Correlatepanel. You Courtesy of Roundabout Logic. can fine-tune the results if...
Orientation
Image courtesy of Apple. Portrait Orientation Image courtesy of Apple. To shoot with the camera in a vertical position, you'll need a bracket that keeps the axis of rotation centered on the optical center of the lens as you rotate it. These brackets hold the camera vertically and allow you to side it sideways to position the lens over the center of the tripod. The Peace River 3Sixty is an indexing panoramic mount compatible with most standard 35 mm SLR film and digital...
Early Panoramic Photographs
The first panoramas, taken in the 1840s, were made by taking a series of daguerreotype images that could then be framed or hung side-by-side. The same approach was later used with tintypes and paper prints. An early panorama of Chicago before the fire. Courtesy of the Library of Congress. An early panorama of Chicago before the fire. Courtesy of the Library of Congress. By the late twentieth century, motorized cameras were being made specifically for panoramic photography. In one type, the lens...
Leveling the Camera
The camera must be as level as possible as you rotate it in a circle so the photographs will line up when they are later stitched together. Some tripods have twin-axis bubble levels to guide you, but you can also use a small handheld level. One of the problems with leveling a tripod is that the place where you mount the camera and the join where the head rotates aren't necessarily aligned. This means that you can level the mounting area and it will become out of level as you rotate the head....
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The CCD shifts one whole row at a time into the readout register. The readout register then shifts one pixel at a time to the output amplifier. It is technically feasible but not economic to use the CCD manufacturing process to integrate other camera functions, such as the clock drivers, timing logic, and signal processing on the same chip as the photosites. These are normally put on separate chips so CCD cameras contain several chips, often as many as 8, and not fewer than 3. Image sensors are...
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When it's cold out, keep the camera as warm as possible by keeping it under your coat. Always carry extra batteries. Those in your camera may weaken at low temperatures just as your car battery weakens in winter. Prevent condensation when taking the camera from a cold area to a warm one by wrapping the camera in a plastic bag or newspaper until its temperature climbs to that in the room. If some condensation does occur, do not use the camera or take it back out in the cold with condensation...
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Cleaning the Camera and Lens
The outside of the camera can be cleaned with a soft, lint-free cloth. Open the flaps to the memory and battery compartments occasionally and use a soft brush or blower to remove dust. Rubbing alcohol (isopropyl alcohol) on a Q-tip can be used to clean metal parts of the camera if necessary. The first rule is to clean the lens only when absolutely necessary. A little dust on the lens won't affect the image, so don't be compulsive. When needed, use a soft brush, such as a sable artist's brush,...
Compression
When you take a photograph, the size of the image file is huge compared to many other types of computer files. For example, a low-resolution 640 x 480 image has 307,200 pixels. If each pixel uses 24 bits (3 bytes) for true color, a single image takes up about a megabyte of storage space. As the resolution increases, so does the file size. At a resolution of 1024 x 768, each 24-bit picture takes up 2.5 megabytes. To make image files smaller and more manageable, almost every digital camera uses...
Dye Sublimation Printers
At the high end where quality is very important, you'll find dye-sublimation printers (called dye-subs, but more accurately dye-diffusion). The dye in the name comes from the fact that the process uses solid dyes instead of inks or toner. Sublimation is the scientific term for a process where solids (in this case dyes) dyes are converted into a gas without going through an intervening liquid phase. The Olympus P-400 is a high-speed dye-sublimation printer that prints an A4-size ( 8.25x 11.7)...
Email Someone an Image
Once photos are in a digital format, there is almost no end to what you can do with them. One of the most popular uses is e-mailing them to friends and family. To do this, you just create an e-mail message the way you normally do and use your e-mail program's Attach command to select the image file you want to send (most programs will let you browse to find it on your system). When you e-mail a message with a photo attached, it is sent to the recipient's service provider where it is stored on a...
Evaluating Your Prints
The first step in evaluating a print is to examine it carefully. Ideally, the brightness and color of the light should be the same as that under which the picture will finally be viewed. This is seldom completely practical, but you should at least be aware that viewing conditions affect the way a picture looks. When viewing your prints, you can use either window or electric light as long as it's bright enough to see details clearly. Avoid very dim light, not only will the print be hard to...
Exploring Color Depth
This figure and Part 4 on the Excel worksheet 'Image Size Calculator calculate the total number of pixels in an image when you enter the images width and height in pixels. 1,920,000 pixels 46,080,000 bits 5,760,000 bytes Black and white Windows display Gray scale or 256 colors High color True color 1. Enter any bits per pixel from the table of color depths (on line 7 and following) on this line. 2. A formula on this line calculates the number of possible colors by raising the number 2 to number...
Exploring Print Sizes
This figure and Part 3a on the Excel worksheet Image Size Calculator calculate the size of print you can expect from a given file size and printer resolution. 1. Enter the width of the digital image in pixels on this line. 2. Enter the height of the digital image in pixels on this line. 3. Enter the number of dots per inch (dpi) printed by your printer on this line. 4. A formula on this line calculates the horizontal size (width) of the image in inches by dividing the image's width in pixels by...
Flash Pix File Format FPX
Most file formats present photographers with a dilemma. Low-resolution images are fine for display on the Web but high-resolution images are much better for printing and publishing. Large high-resolution files make both editing and display time-consuming. The FlashPix format developed by Kodak, Hewlett-Packard Company, Live Picture Inc., and Microsoft attempted to solve these problems. Images in the FlashPix format are stored at multiple resolutions, and each resolution is further subdivided...
Forums and Discussion Groups
Similar to Newsgroups, forums or discussion groups are generally offered on various Web sites and deal mainly with topics related to the site manager's interests. You can read posts by other users or post you own questions or comments. HindSight Forums are sponsored by a company that publishes image management software for the Macintosh. Kodak Discussion Forums where you can discuss digital photography and Kodak products and services ACE Photographic and Imaging Forum. Feel free to post...
Get Yourself an Image
If you don't yet have a digital camera, get some of your own film images put on a floppy disk or even posted to the Web where you can let others see them. Just call around your local photofinishers and ask if they can put images on the Web or on a disk for you. They can usually do this when the film is developed or later, after you have had time to select only the best images. There are a number of companies that offer these services. To learn more about how they work, just visit the PhotoNet...
Halftones and Dithers
On most printers (dye-sub is an exception), each printed dot has the same density of color. If the printer only combined these solid colors, it would be limited to the eight primary colors describe above. To get the millions of colors in a photograph, the printer has to fake it by generating a pattern of small dots that the eye blends to form the desired shade. This process is called halftoning or dithering and designing printer software that does it well is as much art as it is science. As a...
Inks and Longevity
As with papers, there are two important points about inks their quality and their durability. Most inks fade very quickly when exposed to direct sunlight. However, most also fade in dim light so you can't count on hanging them on the wall for years like you can traditional photographs. Inks are improving and some, like Ilfojet Archiva Ink will last 20 years before fading 25 . Some printers place a protective film over the final image to protect it from mechanical abrasion and from UV light that...
Internet Photography News Groups
Usenet (Users Network) is a collection of thousands of ongoing topical discussions called newsgroups. Each newsgroup covers a specific topic such as alternative living or zoology. Also known as bulletin boards or discussion groups, newsgroups are used by people to share common interests. Usenet is not a part of the Internet, or even a network of any kind. It is system for carrying on discussions that can be delivered in a number of ways, the Internet being just one of them. A complete listing...
Internet relay Chat IRC
IRC is a very popular way to chat with other users in real time. In IRC, the chat rooms are called channels and there can be any number of people on a channel at any one time. Since so many discussions can be interleaved, this isn't for everyone. It's like an Internet CB radio. To chat, you first need to download and install chat client software. One of the most popular Windows chat clients is mIRC. Once the IRC software is installed, you then need to find a channel that's discussing something...
Kodak Picture Makers
In camera stores, you may have seen Kodak Picture Makers. These easy to operate, self-service printers make prints from prints, slides, negatives, photo CD discs, Digital camera memory cards, and JPEG and FlashPix-format floppy diskettes. To do this, the station has integrated drives, scanners, printers, and a display monitor. Before making a print, you can zoom and crop, use red-eye reduction, adjust color and density, and add mattes and borders. You do all of this by making simple choices...
Large Format
When you want poster-sized prints, you have to locate a large format ink-jet printer. These printers feed large sheets of paper much like a plotter and the ink-jet printing head lays down lines of ink as the paper passes through the printer. One large format printer from HP prints 2' by 3' images at 600 dpi. Generally you'll find these printers at service bureaus where they'll charge you by the size of the print. The Tektronix Phaser 600 is a solid ink printer that can print a 34 x 44 print in...
Lossy compression
Although it's possible to compress images without loosing some quality, it's not practical in many cases. Therefore, all popular digital cameras use a lossy compression (rhymes with bossy) that degrades images to some degree and the more they're compressed, the more degraded they become. In many situations, such as posting images on the Web, the image degradation isn't obvious. However, enlarged prints show it off. Although lossy compression does not uncompress images to the same quality as the...
Native and Transfer Image Formats
Bitmap file formats fall into two subclasses native and transfer or exchange formats. Native Formats As new programs are introduced, developers have a tendency to create proprietary, or native formats that can be read only by their programs. Part of this desire is to have a competitive advantage. But there is also a need sometimes to design a new format to accommodate new procedures or possibilities. However, native formats present serious problems for users who want to...
Object Photography
Object photography is the opposite of panoramic photography. Instead of standing in one place and rotating to see a 360-degree view, object photography rotates an object for you so you can see all of its sides. To create a rotational object, you start with a series ofimages showing the object from various angles. Images courtesy of Peace River Studios. To create a rotational object, you start with a series ofimages showing the object from various angles. Images courtesy of Peace River Studios....
One Shot Panoramic Camera
Be Here's Portal S1 panoramic lens system uses a standard 35-mm camera body mounted facing straight up and shooting through a hole in a parabolic dish. The surrounding 360 degrees image is reflected off the top of the parabolic dish, then bounced off a small mirror that focuses it down into the camera lens. When taking a photo, you have to stand under the dish to stay out of the field of view. (In 1998 a digital video camera will be introduced so it can be used in place of the 35-mm camera.)...
Panorama Viewing Software
You can post static panoramic images on the Web in the usual JPEG format. However, it you want to add interactivity to them, you need to choose an interactive format to save them in. The great thing about panoramas, especially 360-degree views is that you can pan and zoom them. From a central observation point, called a node, a viewer can look in any direction and may zoom into or out from a particular view by changing the zoom angle of their view. Panoramic viewing is similar to, but different...
Papers Inks and Longevity
Papers and inks have affects on both the initial image quality and eventual archival quality. When images fade, memories are lost. This has been a problem throughout the history of photography. Most papers, inks, and toners have unknown archival qualities. If you have the original digital file, this is no problem. But will you be able to find it ten years from now And if you can, will the media still be readable. No media is permanent and you may be out of luck. To check on the archival quality...
Pinhole Panoramics
Surprisingly, lenses are not actually needed to take a picture. You can make a camera out of a shoe box with a small hole in one end. Known as a pinhole camera, this primitive device can actually focus an image and record it on film. To make a photograph, the box is loaded in the dark with a light-sensitive film or paper and the pinhole is covered with opaque tape. Peeling the tape back (much like a shutter) to uncover the pinhole (much like a lens aperture) begins the exposure, recovering the...
Point and Shoot Panoramic Cameras
Point-and-shoot 35mm panoramic cameras, including the latest APS cameras in panoramic mode, just mask out the top and bottom of the ordinary 35mm frame, leaving a long thin image in the middle of the frame. This doesn't change the horizontal angle of view, it just crops out the top and bottom of the image to give a panoramic look kind of a faux panorama. Kodak MAX panoramic one-time use cameras are an inexpensive way to experiment with panoramic photos. Courtesy of Kodak. A slide from a point...
Preparing Images for the
When creating images for the Web, the most important thing is to keep the images small maybe 20 Kilobytes or so. If one takes longer than a few seconds to load, the viewer has probably moved on. Here are some other things to consider that either improve the image or make it smaller. When editing an image, use the highest possible resolution and color depth. Be sure to save this file in the program's native format or a format such as BMP or TIF that uses lossless compression. Use your program's...
Protecting Your Work
Watermarks were first used in Europe to identify the guild that manufactured paper. They were like trademarks or signatures. Watermarks in paper are created by varying the paper's density. Normally invisible, a watermark image becomes visible as darker and lighter areas when the paper is held up to the light. Wire or relief sculptures are placed in the paper mold and when the paper slurry is drained of its water and dried the thinner areas created by the wire or sculpture show clearly when held...
R t
These sample images were scanned into the computer from contact prints. The actual images are of photographic quality since they are made from the actual negatives. Click to enlarge the image. Courtesy of photographer Everen T. Brown. David Grenewetzki takes digital photos from rockets and remote control airplanes. To take panoramas with a remote control and a Kodak DC20 camera he designed and built this device that repeatedly turns the camera 45 degrees and takes a photo until eight pictures...
Resolution and Resolving Power
As you saw in Chapter 2, there are two types of resolution. Optical resolution is the native resolution of your scanner as determined by the optics in your scanner hardware. Interpolated resolution is resolution enhanced through software, and is useful for certain tasks such as scanning line art or enlarging small originals. However, in photography interpolation adds no new detail to the image yet makes the file size a lot larger. For these reasons, you should never scan a photograph at a...
Rotating Cameras
Rotating cameras can capture a 360-degree image by revolving in one direction while the film moves in the other so it's synchronized with the lens motion. As in a swing-lens camera, light focused through a narrow slit paints an image on the film. Cameras in this category include the SpinShot. Hulcher, and those made by Roundshot and Globuscope. The Spin Shot 35 S captures an entire 360 degree scene. As the Spin Shot 35 S rotates, it automatically pulls the film across the shutters narrow...
Scanning an Image for Screen Display
Scanning an image for the screen is the same as scanning one for printing except the output is usually specified in pixels, not inches. Although the actual number of pixels per inch on a monitor vary depending on its size and resolution, images are generally scanned at 72 ppi for screen display (although they are sometimes scanned up to 96 ppi). Making them any larger doesn't add any information to the image and just makes the files larger. 4. Scanning an Image for Screen Display 1. Enter the...
Scanning Black Magic
Scanning on one level is simple, plop a print on the copyboard and click the Scan button. However, to get the best results, there are lot's of little things that need tweaking. Here are some of them. Two terms are used interchangeably when scanning and printing dots per inch (dpi) and pixels per inch (ppi). This has been done to add a little confusion to all discussions. Image quality improves as resolution increases. However, there is a point of diminishing returns at which the image file just...
Scanning and Files Sizes
1 Size of Original Horizontal 10.00 inches 2 (in inches) Vertical 8.00 inches 3 Scanner's Resolution 1,200 dpi 3 Scanner's Resolution 1,200 dpi 1. Enter the width in inches of the art to be scanned. 2. Enter the depth or height of the art to be scanned. 3. Enter the scanner's optical resolution or the resolution to intend to scan at. 4. The scanned pixels horizontally are calculated by multiplying the scanner's resolution (line 3) times the horizontal size of the original (line 1). 5. The...
Scanning Images Yourself
When you first start scanning and printing images, it seems like there is a black art involved. Actually, it's not that at all, you just have to understand some relationships between pixels and inches. Here we'll try and explain those relationships so they're understandable. To follow these discussions better, and to calculate your own scanning and print sizes, download the Scan Calculator by clicking the link below. It was created with Excel 97. Download Excel Scan Calculator Scanning and File...
Shutter Glasses
An increasingly popular way to view 3D images on the screen is using shutter glasses. These glasses have high-speed electronic shutters that open and close in sync with the images on the monitor. Liquid Crystals are used for the shutters because an electronic signal can make the crystal turn instantly from transparent to opaque. When the left image is on the screen the left shutter is open and the right shutter is closed which allows the image to be viewed by your left eye only. When the right...
Start Your Own Web Page
There's nothing quite like having your images up on a Web site where anyone in the world can see them. Surprisingly, you can do this without spending a dime because there is a slew of sites that offer you free hosting for personal web pages. All you have to do is register for one of these and then post your images to it. Some sites even provide you with the software you need to lay out your page. Once your images are up on the site, they can be seen by anyone you want to see them. Just send...
Stereo Photography
The First Stereo Photographs Taking Stereo Images Viewing Stereo Images Web 3D Viewers Making 3D Images Stereo Panoramas Photographs are great at rendering the details in a scene but don't readily convey the impression of depth. Everything is rendered on a flat plane. Ever since photography was invented, people have been trying to correct this. There have been hundreds, if not thousands, of stereo patents filed and demonstration devices built. Sir Charles Wheatstone discovered the principles of...
Super Wideangle Cameras
Specially designed cameras with super wide-angle lenses can capture wide slices of a scene but no more than 180-degrees. There are many models of these cameras including the Hasselblad Xpan, Linhof Technorama 617 (115 ) and the Fugifilm Panorama GX617. The Hasselblad XPan provides both a panoramic 24x65 mm format and the conventional 24x36 mm on the same 35 mm film. Its the first and only dual-format camera that expands the format instead of masking it, ensuring that every exposure utilizes the...
Swinglens Cameras
Swing-lens cameras use a lens that rotates from one side of the scene to the other during an exposure. As it does so, light focused through a slit sweeps along the film and paints an image. Since the film plane is curved the image doesn't show any distortion. Lines that are straight in the real world are straight in the image One big advantage of this type of camera is that the lens isn't expensive. It only has to cover the vertical dimension of the film and the width of the slit. Cameras of...
Taking Stereo Images
Almost all-stereo images start with a pair of photographs taken a few inches apart. The effect is to duplicate the spacing of our eyes that gives us stereo vision. Although it's possible to take a pair of stereo images with a single camera and lens, it's not the easiest way and the results are somewhat unpredictable. It's important that the lenses be the same focal length, exactly parallel, and offset by just the right amount called the stereo base distance. For this reason, special cameras are...
The Arithmetic of Image Sizes
A pixel begins its life on the camera's image sensor during that flickering moment when the shutter is open. The size of each photosite on the image sensor can be measured, but the pixels themselves are just electrical charges converted into digital numbers. These numbers, just like any other numbers that run through your head, have no physical size. Although the captured pixels have no physical dimensions, a sensor's size is specified like those in a digital photo, except the count is the...
The Development of the CCD
Based on a press release by Patrick Regan Lucent Technologies, Murray Hill George Smith and Willard Boyle invented the charge-coupled device (CCD) at Bell Labs. They were attempting to create a new kind of semiconductor memory for computers. A secondary consideration was the need to develop solid-state cameras for use in video telephone service. In the space of an hour on October 17, 1969, they sketched out the CCD's basic structure, defined its principles of operation, and outlined...
The First Stereo Photographs
As soon as Henry Fox Talbot's and Daguerre's photographic processes were introduced in 1839, people started making stereo views. In many respects, the results were as good as those we get today. The problem was that the process of making the photos was expensive and there weren't any special or widely available viewers. The big breakthrough came in the 1850s with less expensive albumen prints and viewers the first invented by David Brewster, and a later and less expensive one by Oliver Wendall...
The Screens Resolution
The size of each pixel on the screen is determined by the resolution of the screen. The resolution is almost always given as a pair of numbers that indicate the screen's width and height in pixels. For example, a monitor may be specified as being a low-resolution 640 x 480, a medium resolution of 800 x 600, or a high-resolution of 1024 x 768 or more. (The first number in the pair is the number of pixels across the screen. The second number is the number of rows of pixels down the screen. ) This...
TWAINDont Leave the Store Without It
There's an old expression never the twain shall meet. When scanners were first connected to PCs, that's pretty much the way it was. Everyone had their own proprietary set of protocols that made scanning possible with their hardware or software and a few other products that they choose to support. The problem with this approach was that scanners from different manufacturers were incompatible with many application programs. Before buying a scanner, you had to check if your applications worked...
Two Shot Panoramic Camera
IPIX images are amazing sphere-like images that include every horizontal and vertical aspect of a scene. To create the images, you take two back-to-back photographs using an 8mm lens and a special IPIX tripod mount called an IPIX rotator. You then use IPIX software to stitch the two images into a seamless 360-degree sphere. In addition to viewing these images with a browser and the IPIX plug-in, you can also use a separate viewer. IMEDED IPIX image (http www.ipix.com index.html). Don't expect...
Vector graphics
Vector graphics are really just a list of graphical objects such as lines, rectangles, ellipses, arcs, or curves called primitives. Draw programs, also called vector graphics programs, are used to create and edit these vector graphics. These programs store the primitives as a set of numerical coordinates and mathematical formulas that specify their shape and position in the image. This format is widely used by computer-aided design programs to create detailed engineering and design drawings. It...
Viewing Stereo Images
There are several methods that can be used to create stereoscopic images for viewing on a PC or web page. The most common images are Page flipped images viewed with shutter glasses Line alternate images viewed with shutter glasses and head mounted displays Squished Side by Side images viewed on lenticular displays Polarized images viewed with polarized glasses
What are copyrights
Copyright is a form of protection provided by the laws of the United States (title 17, U.S. Code) to the authors of original works of authorship including literary, dramatic, musical, artistic, and certain other intellectual works. This protection is available to both published and unpublished works. Section 106 of the Copyright Act generally gives the owner of copyright the exclusive right to do and to authorize others to do the following To reproduce the copyrighted work in copies or...
What is fair use
Is copying that article from a Web magazine or newspaper into an e-mail message to a friend fair use Nope, you're infringing the owners copyright. Basically, the copyright law says the fair use of a copyrighted work, including such use by reproduction for purposes such as criticism, comment, news reporting, teaching (including multiple copies for classroom use), scholarship, or research, is not an infringement of copyright. Even for these uses, whether a specific use is fair or not depends on a...
What is public domain
When something is in the public domain, you're free to use it any way you see fit. However, you are still expected to credit the source and not claim it as your own. How do you know if something is in the public domain Partly it is common sense. Recent ads, logos, cartoon characters, illustrations, or photographs are almost certainly not in the public domain. However, 18th-century photographs and illustrations most likely are. In that gray area from 1900 through 1970 or so, some things remain...
Whats a Color Model and Color Space
As a photographer, you've seen colors change as the source of the light changes. It even changes out of doors as the sun makes it's arc across the sky. If colors change so easily, how then do we get an absolute handle on them We do so, by measuring them under very controlled conditions and assigning numbers to them. The first such system was the CIE color system developed in the 1930s. Colors are read by colorimeters (color light meters) and plotted on a chromaticity diagram. This assignment of...
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Image sensors record only the gray scale a series of 256 increasingly darker tones ranging from pure white to pure black. Basically, they only capture brightness. 0 10 20 30 40 50 60 70 G0 90 100 The gray scale contains a range of tones from pure white to pure black. 0 10 20 30 40 50 60 70 G0 90 100 The gray scale contains a range of tones from pure white to pure black. How then, do sensors capture colors when all they can do is record grays The trick is to use red, green, and blue filters to...
So you Have to Know Arithmetic After
The Arithmetic of Image Sizes The Arithmetic of Displaying Images The Arithmetic of Printing Images Understanding Pixels Per Inch The Arithmetic of Color Depth Let's start with one surprising fact A pixel has no size or shape. At the time it's born, it's simply an electrical charge much like the static electricity that builds up on your body as you shuffle across a carpet on a dry day. A pixel is only given size and shape by the device you use to display or print it. Understanding how pixels...
Image Sensors and Pixels
Digital photographs are made up of hundreds of thousands or millions of tiny squares called picture elements, or just pixels. Each of these pixels is captured by a single photosite on the image sensor when you take the photo. Like the impressionists who painted wonderful scenes with small dabs of paint, your computer and printer can use these tiny pixels to display or print photographs. To do so, the computer divides the screen or printed page into a grid of pixels, much like the image sensor...
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Your photofinisher can arrange to have your slides or negatives scanned onto a Kodak FlashPix CD, or a Picture Disk Plus floppy disk. The PictureWorks FlashPix Format Viewer is included on every Kodak FlashPix CD so you can view the pictures and make minor picture enhancements. To view FlashPix images on the Web, you need a FlashPix viewer. To edit and save FlashPix images with Photoshop you need the FlashPix plug-in. Both are available in The Digital Photographer's Toolbox. The FlashPix format...
Scanning Formats
This is something of a made up category since it has only a single entry Photo CD disks. Although film and print scanners have become very common and are widely used to scan images for storage on CD disks, the Photo CD from Kodak was the first widely available such format. Kodak originally hoped that these discs would catch on in the consumer market. The plan was to have mom or pop select the best photos from their vacation and have Kodak scan them onto a CD disc. The family would then gather...
What Kinds of Digital Photos are being Taken
People like David Grenewetzki think nothing of strapping their new digital camera to a remote control airplane, or even a rocket, and launching it into the wild blue yonder to capture photos from a bird's-eye view. Until camera prices come way down, you might want to find other applications for your new camera. What could be more fun than strapping your new camera onto a remote control airplane for pictures from hundreds of feet up Check out David's site for lots more on this and rockets too....
