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Spotlight on Digital Projectors
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by Yu Bong Ko
Tappan Zee High School
Orangeburg, New York
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| | The Digital Debate
AP Art History teachers across the country are finding success by converting their slide collections to digital format. They are also discovering that with the aid of a reliable computer digital projector, the paired images simultaneously displayed on a single large screen consistently yield results comparable with those achieved using the traditional two-slide-projector system with two screens.
In going beyond the "slide versus digital" debate, one has to think differently about projecting images on the screen when using a digital projector in place of a slide projector. Teachers showing digital images encounter some of the same issues and concerns that exist when showing slides in the classroom -- but with a slight twist.
Digital Projector as "Output Source"
- To a large degree, the kind of digital projector you choose determines the quality of the projected image. The computer digital projector is a critical factor in the equation because it is the "output source." Although you can be very selective about acquiring high-fidelity digital images, what you see initially on the computer monitor is not necessarily what appears on the screen.
- The quality and the price of these projectors vary greatly. Expect to pay from $1,000 to $1,500 for a budget model,$2,000 to $4,000 for a midrange model, and $5,000 to $10,000 for a deluxe one. In addition, figure in the cost of a single replacement lamp at $300 to $500, each with a life span of between 1,000 and 3,000 hours, depending on the quality and maintenance of the lamp. To put these costs into perspective: you can purchase a midrange traditional slide projector for about $500 and a replacement bulb for $10.
Projector Specifications
- Digital projector model specifications include brightness (lumens), resolution (pixels), range of image size (for example, ability to project an image as small as three feet to a maximum of 30 feet), optical zoom and contrast ratios (the higher the numbers, the better), internal speaker capability, and weight and size of the unit.
- The most desirable projectors are multimedia with digital light processing technology. They provide an interface capability with many hardware devices such as a VCR, DVD player, and digital camera. In addition, recent models offer wireless technology and slick remote controls that allow greater fine-tuning of the projected image.
Tips for Using a Digital Projector in the Classroom
- The clarity and size of the projected image depends upon the positioning of the projector and its distance from the screen. By knowing the maximum projected image range of the projector unit, you can easily show a combined pair of images from a single PowerPoint slide, thus eliminating the need for a second projector. You can project the paired images simultaneously on a single large screen, yielding results comparable with or exceeding those currently achieved by two slide projectors and two screens.
- For more information on the use of digital images in teaching art history, see the following articles on AP Central:
 Accessing and Using Digital Images in AP Art History
Using PowerPoint Slides in the AP Art History Classroom
- It is important to have a large screen to comfortably accommodate and correctly project pairs of digital images at a distance close to the maximum range of the projector. The ability to project paired images is critical since the current format of the AP Exam includes several free-response questions that specifically ask students to compare and contrast two works displayed side by side from separate slides.
- As an alternative to PowerPoint presentations, you can access raw databases of images on a CD, for example, using a "viewer" application on the computer. This can vary from computer to computer, although in the PC platform, you usually accomplish this task through the Windows Picture Viewer. These viewer applications have the capability to zoom in on a particular section of the image.
- Through an on-screen menu, you can easily and remotely control digital projectors to adjust keystone, brightness, contrast, and color balance. Despite this range of control, it is important to remember that while images may look correct on the computer monitor, they can appear differently when projected.
- Many schools have ceiling-mounted projectors only, with pull-down screens set at a fixed distance. While this type arrangement discourages theft, it limits the way a teacher can customize the room to accommodate different class sizes and arrangements. My class size varies from year to year. I like the flexibility of having the projector on a cart. I can move the projector at will to accommodate variations in enrollment and conditions of the classroom. In addition, I can connect other external devices, such as a DVD player, and place them on the same portable cart with relative ease.
- Don't be too eager to throw out the traditional slides and "old-fashioned" projectors. I am fortunate to be using both slides and digital images in my own art history classroom; there are distinct advantages to both setups. As much as I have embraced digital technology in my teaching for its unsurpassed ease of use and flexibility, I find that good-quality traditional slides still deliver the best images in a darkened room. On the other hand, one major advantage of using a digital projector is that a few lights can stay on. Even with some of the lights on, the projected images remain clear. As a result, students can see their notes under better light conditions. An advantage for the teacher is that it promotes better eye contact with students during lectures and discussions.
Equity and Access Issues in Using Digital Projection on the AP Exam
- At this time, there are some major obstacles to transitioning to digital projection for the AP Art History Exam. Although an experienced user can adjust the projector settings to display the best image on the screen, incorrect settings can cause many distortions of the original image. An erroneously set keystone, for example, can project images that are too wide or too narrow. Similarly, inaccurate color balance or contrast can distort the image enough to mislead the student on the exam. Although most computer projectors have automatic image display and resize features, they do not always respond properly, hence requiring manual adjustments. Moreover, exam administrators must take into account computer settings and other hardware and software capabilities when using digital projection. The College Board does not permit the AP teacher to be present in the examination room or allow the teacher to view the images ahead of time to help resolve potential technical problems. Thus using digital images on the AP Examination would greatly compound the range of variances related to providing a common digital image for all students. Unless the College Board can specify all the settings and capabilities precisely for each computer and projector, the degree of variance will be unacceptable to guarantee equity in the exam administration.
- The degree of variance among schools that have access to the latest technology may well be equally unacceptable to guarantee equity in the exam administration. While many schools have a digital projector and a multimedia computer in every classroom, other schools still struggle to gain access to even one setup in the entire building. The precise technical specifications would impose additional financial burdens on schools that would need to acquire projectors and computers with all the requisite hardware and software capabilities. This financial burden would especially affect schools that use multiple rooms to administer the exam.
For more on equity and access issues in using digital projection on the AP Exam, see:
Image Projection for the AP® Art History Exam Administration
Yu Bong Ko teaches AP Art History at Tappan Zee High School in Orangeburg, New York, and is an adjunct professor of education at New York Institute of Technology, where he teaches graduate courses in instructional technology. A frequent speaker and session leader at AP teacher conferences and summer institutes, he continues to read AP Examinations and is a former member of the AP Art History Development Committee.
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