What is contrast?
Contrast is the difference in brightness between maximum white and deepest black in an image. The greater the difference, the higher the contrast. Why is Contrast so important? With business projectors, lumen output is of primary importance, and contrast is a secondary concern. Home theater projectors are the exact opposite. Contrast is arguably the single most important measurable quality in a home theater projector. A high contrast projector produces a picture with a rich, dynamic look, good shadow definition, and deep color saturation. Contrast gives “depth” to video images. A projector with excellent contrast can make a two-dimensional image appear almost three-dimensional. Contrast Ratios The contrast ratios noted on a projector’s spec sheet can be reported in one of two ways. If it just says “Contrast,” it usually indicates On/Off contrast, which is the ratio of the whitest white and the darkest black that the projector is capable of producing. If it says “ANSI contrast,” the rat
• For a CT scan, there are two types of contrast, oral & IV (injection). • For certain abdominal and/or pelvic examinations you will be asked to drink an oral contrast prior to the exam. If so, you will need to be NPO (without food or drink – other than water) for 4 hours prior to the exam. • With oral contrast you will either need to arrive one hour before the scan time to drink the contrast and allow it to get into your system, or you can talk with one of our staff members about picking up the contrast and instructions for drinking the contrast prior to your arrival. • It is appropriate to take any prescribed medications prior to the exam. • An IV contrast may also be administered. With IV contrast you may feel a warm sensation. There is no preparation by the patient for this contrast.
