DLP vs LCD projector tech: pros and cons

Projectors are awesome. You get an ultra-huge screen for a reasonably low price. But there are two key technologies projectors use to create an image: DLP and LCD.. But what’s the best? 

First, the abbreviations:

• DLP, or digital light processing, uses tiny mirrors to reflect light towards or away from the screen. And most models use a colour wheel, a spinning wheel with colour filters, to create sequential colour. Some high-end models use three DLP chips; one each for red, green, and blue.

• LCD stands for liquid crystal display, is very similar to the technology found in most TVs. LCD projectors use three liquid crystal panels, each tasked with creating an image using one of the primary colours. All three are projected on the screen at once, so you see a full-colour image.

Each technology has positives and negatives, and there are good and bad projectors that use each technology. But what should you look for when choosing a projector? 

Contrast ratio

Contrast ratio is the most important aspect of picture quality. It is the primary determinant for how realistic an image looks. Contrast ratios of LCDs have come a long way, and some offer excellent picture quality, with DLP technology falling behind. 

Most projectors have an auto iris, which closes to dim the image on dark scenes, and remains open to keep bright scenes bright. Though you might sometimes notice the opening and closing, but you can turn the auto iris off if you don't like the effect.

Black level

A projector's black level refers to the darkness of the black it can reflect. Not every black is the same. With this in mind, getting better black level performance out of your projector means that you are making it easier to see details in dark areas of projected images. This is especially important when you are projecting video, as opposed to slides, which typically have brighter colours and high levels of contrast.

Light output (brightness)

Light output varies a lot, so to be honest, all projector types are 'adequate' in this regard, it's the brand and model that differs.

Colour

Colour accuracy varies a lot. We’ve used many projectors with accurate colour from all technologies; our advice is to check reviews to see if the model you're considering performs well in this regard.

Motion blur

Motion blur, or the softening of a moving image, is a problem with LCD displays. Some people aren't bothered by it, but others notice it. Side-by-side, a DLP projector will look sharper and more detailed during fast motion than an LCD projector. But, this is not enough to offset the DLPs poor contrast ratio performance. 

Rainbows

Have you noticed it before? Bright objects (in particular on a dark background) appear to have trails of multicoloured light. Three-chip projectors, like LCD and high-end DLP models, don't create rainbows. But single-chip DLP projectors, however, create an image using sequential colour, i.e., in any given fraction of a second, there's just one colour on the screen. This is done so fast that your brain combines it into a full-color image (mostly). Some people are susceptible to ‘rainbows’, and their brains registers the sequential colour especially when you move your eyes rapidly around the screen or bright objects are moving on a dark background. 

If rainbows bother you, don’t buy a DLP projector. With faster colour wheels, and the shift to LED and laser light sources, rainbows are much less apparent than they used to be, or if the budget allows splash out on a three-chip DLP projectors. 

Convergence

The chips that create an image in a projector are minuscule, and even tiny variations in the position of each chip can be visible on the screen. These can look like coloured edges to white objects or, worst case, softness. Most three-chip projectors come with convergence adjustments, but these can't always eliminate convergence errors. Worse, it's hard to tell from reviews if a projector has good or bad convergence, as it varies on a unit-by-unit level. On the other hand, single-chip DLP projectors, don't have convergence problems because there's nothing to converge. 

So that’s it. But what is most important, is what is giving whoever is viewing your projected content, the experience. So weigh up the pros and cons and pick the best projector type and make/model for your budget.