There are two key projection technologies. DLP models use a digital micromirror device (DMD) allied to a spinning colour wheel to create images. They tend to be competitively priced and because they use a single device, can deliver very sharp pictures. However, that colour wheel can cause an artifact known as rainbow fringing (particularly on cheaper models), where colour flashes can be seen in areas of high contrast. If you specialize in monochrome, they may not be the best choice.
3LCD projectors use a trio of aligned LCD panels. These projectors give the most cinematic of images, with naturalistic color, but often don’t seem quite so sharp as DLP.
In most rooms, you’ll need at least three meters (ten feet) of space to cast a 100-inch display. If that’s not possible, consider an Ultra Short Throw projector. These sit up close to your projection screen (or wall), often less than 10cm, but use mirrors to throw a large projection. Remember, in all cases, image resolution will determined by the projector hardware in use.