What projector user wouldn't want the best setup for their projector? But whether a ‘best setup' even exists is a topic of endless discussion - whole internet sites are devoted to it. Supposedly, you can achieve dramatic increases in contrast, at the same time as correct grayscales and authentic movie colors, all by simply tweaking a few settings. Is it true?

Introduction

Well, let's assume that it is indeed possible. The next question is: why don't manufacturers set their devices up that way in the first place? Well, the answer to that is tricky: In today's marketing-mad world, manufacturers have to tease the highest measurements possible out of their devices. Put simply: higher numbers sound better.

So a projector that outputs 500 ANSI lumens stands no chance when faced with models claiming to give you 1,000 ANSI lumens. It's just like with cars: People check out how many horsepower a model produces, and take that as an indication of performance. But various other factors are involved; a removal van, for example, even with several hundred horsepower, isn't exactly going to burn rubber.

The game of one-upmanship has gone so far that customers now expect manufacturers to top each other with ever-higher numbers, irrespective of whether they actually need more performance - or at least that's what the manufacturers seem to think. No one points out that the light output in movie mode, with optimized colors, will often scrape just 400 lumens; little therefore remains of the 1,000 ANSI lumens, which might only perhaps appear in the dynamic mode.

This shows what a complex problem the manufacturers are facing. But, unavoidably, the problem carries through to the end user - the buyer sees a high number of lumen and often tends to ignore other factors. But it's precisely these factors that can boost a projector's performance enormously if tuned correctly. There are plenty of places to start, but many are fraught with problems. Televisions.com would therefore like to introduce a few tricks to help you pep up your picture.

This diagram illustrates the kind of problems with which the common UHP lamps must struggle. Their light always contains an excess of green, often also with too much blue (green line); the red component, on the other hand, is typically too weak. Daylight (blue line) and expensive xenon lamps (red line) are more uniform in their frequency distribution.

Filter tuning

For some projector-tuning fans, filter tuning is the first - although not the easiest - starting point. And there are good reasons for this, considering the quirk of the UHP lamps used in almost all projectors. The excess green that these lamps produce is the major source of the device's quoted brightness. The resulting green-tinted image is fine for a PowerPoint presentation, for example, but unacceptable in the home theater.

Putting a magenta filter (magenta is green's complimentary color) in front of the lens will cap the green excess, giving better color neutrality. Of course, you can then no longer achieve the maximum brightness - part of the energy is absorbed by the filter. And simply mounting a filter won't fix everything; the user must also optimize one of the projector's picture modes especially to use with the filter - in general, the factory setup lacks presets for this type of use.

So, we've seen that a filter can help provide neutral colors. But that's not the actual advantage of a filter - in fact, you can achieve color-neutrality electronically, using controls for the individual colors, which the manufacturers use in the movie mode. So what's the advantage of a filter? Well, a projector's construction determines its optical characteristics - weak blacks can be a result of scattered light in the beam's path or, for LCD models, the transparency of the panel. By capping the particularly intense greens, a filter also improves the black level, or the amount of light displayed when representing ‘pure' black. The light that's capped in the green section is missing in the blacks, which means the residual illumination is lower. You can see this effect clearly in the following diagram:

There are two ways to achieve a better black level: either using a filter or with electronics. The difference lies in the amount of residual illumination.

Problems associated with using a filter

What we've described so far might work beautifully in theory, but what's it like in practice? And are there any disadvantages? In fact, we should establish whether or not you're actually doing yourself a favor by installing a filter - and, as a result, tampering with the work of the manufacturer. After all, you'd think twice about changing your car's engine. In both cases, the components were developed by paid specialists - and these guys know what they're doing. Besides the necessary know-how, projector developers also have contacts from which they source the best components for their products - this is especially important for optical components.

One of the biggest problems with using a filter is the sheer quantity of light that a projector produces. Most filters are made for use with cameras, whose optics never has to deal with the amount of energy that a projector's lens withstands. The result is easy to imagine: The heat involved means that the filter's characteristics change within just a few hours of use, meaning all of that fine-tuning work was for nothing.

Instead, some people use filters from the stage and movie industry, where they're used to adjust the color balance. These filters have no problem handling the powerful light in a projector's output, but still bring some disadvantages: They scratch very easily, are hard to clean, and are prone to creasing. So, this is also no ideal solution, although it's still better than using a camera filter. For filters to be of genuine benefit - and to avoid wasting energy unnecessarily - they must very precisely suit the requirements of the projector's light spectrum; otherwise, in certain circumstances, they can make the results worse. Essentially, tuning filters are actually used at the wrong point in the light's path - namely, between the projector's lens and the screen. Here, they do more harm to the ANSI contrast and scattered light than if they sat directly after the projector's lamp.

Epson's TW-series projectors have indeed shown that it makes sense to put a light-filter inside the projector. Here, when the projector enters movie mode, a filter automatically moves into the light's path and corrects the projector's light spectrum to produce the ideal D65 color temperature - that is, a neutral result. So, our ultimate opinion of fitting filters on the front a projector: it's an extremely risky business - better not to get involved in the first place.

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