Common projector problems

Last updated on December 9th, 2019 at 05:40 pm


The two most common projector problems

There are two (relatively) common projector problems: the screen-door effect and rainbow effect. It’s important to know that the likelihood of these occurring in modern projectors is pretty low. Nonetheless, there are still foolproof ways to avoid this happening on your device. 

The screen-door effect 

The screen-door effect occurs when the spacing between the pixels in the projected image is visible. This makes it look like you are viewing the image through a fine mesh screen. It is a common occurrence in low resolution projectors and some VR headsets. Although it doesn’t distort the projected image, it is an annoyance and has a definite impact on image quality. The same pattern could be seen if you held your phone under a magnifying glass or stand too close to an old TV, so it isn’t by any means a new phenomenon. 

As with holding a magnifying glass over your phone, scaling an image to a large size can cause this effect. It makes sense that there should be a positive correlation between scaling an image and projector resolution, right? 

Summary: Screen-door effect provides a fine mesh over the projected image. It is only apparent in low resolution projectors when you sit too close to the screen.

Common projector problems: screen-door effect
Source: Flickr, Pål-Kristian Hamre


There are two solutions to reducing or completely getting rid of the screen door effect for projectors. 

The mesh lines that appear are very thin lines only visible when you’re close to the projector. Because of this, the further you move away from the projected image, the less likely you are to see them. If the sizing of the room your projector is in doesn’t allow for this, perhaps it’s worth sacrificing on image size. By Either moving your projector or using it’s zoom (if available) you can change the projected image size. Of course, this is much easier if you aren’t using a projector screen. 

This effect is also only apparent in low resolution projectors. Once you hit the 1080p mark you aren’t going to have this problem. So go for that big screen size and sit as close as you like! However, if you’re only using your projector for business or classrooms, this effect really is not reason enough to upgrade. The likelihood is, only the person presenting is close enough to notice it.

The rainbow effect 

The rainbow effect is only present in single chip DLP projectors. In these projectors the light goes through a spinning RGB colour wheel, to the DMD and then projected. As such, a projector displays colours sequentially to build an image, meaning they show the entirety of one colour before moving to the next. The wheel spins too quickly for us to be able to see these colours individually, but can create two annoying byproducts. Firstly, the colour wheel when spinning tends to make a buzzing noise some find annoying, but others can block out. Secondly, the rainbow effect. 

The rainbow effect, although sounding quite innocent, can become a huge burden on image quality. The effect is essentially when you see flashes of red, green and blue over an image. However, not everybody is susceptible to it. If you’re part of a group that can’t see it, don’t go looking for it. 

Summary: The rainbow effect flashes red, green and blue across the projection. It is only common in old single chip DLP projectors. 

Common projector problems: Rainbow effect
Rainbow effect


Unfortunately there aren’t too many solutions for this other than purchasing a new projector. Often the rainbow effect is only seen when the colour wheel spins too slowly. Of course this is more apparent in older and cheaper projectors. Further to this, the effect only becomes significantly evident when prominent white objects are against black backgrounds.

This by no means should discourage you from buying a DLP projector, perhaps just ensure you can either test it out first or lean in the direction of a 3 chip DLP projector. If you’re worried about your susceptibility to the rainbow effect, think about investing in either an LED or LCD projector instead. 

Other common projector problems

Don’t be fooled into thinking these are the only problems that can be faced, there’s also: 

  • Overheating
  • Light Dimming 
  • Taking time to turn on

Projector overheating

Often in bulb projectors, overheating can occur. This is usually combated with a fan, however in cheaper projectors this is sometimes obsolete. 

This is because a byproduct of heat is light. In modern styled lights, such as LEDs, this isn’t the case. But in traditional bulbs, in order to produce the bright light your projector needs, heat must first be produced. 

Similarly to other electronic devices, your projector needs space in order to breathe. If your projector overheats, try placing it alone, without other objects surrounding it. Furthermore, try to keep the room temperature down and not to use your projector for extended periods of time. 

If you’ve paid over $500 for your projector and keep facing this problem, it’s time to contact the manufacturer. 

Projector dimming

If your projector is dimmer than when you first bought it, this can be a concern. It’s important to understand your projector has a “bulb life”. That is, it will only be able to function using the bulb for a maximum time, which is usually displayed by the manufacturer. 

However, the “maximum time” isn’t a guarantee. It is merely to manage your expectations and sometimes can be exaggerated a little. As with anything, the more you use your product, the less efficient it will become.

Common projector problems: projector dimming
Dim projector

When your projector light is dimming, it means your projector might need a bulb replacement in the near future. This usually isn’t too expensive, nor difficult to do. If you own a laser or LED projector, it is almost impossible to do and highly expensive. This means it could be time for an upgrade soon. 

Projector taking time to turn on

Often, people are confused as to why their projector takes a few minutes to turn on. Simply put, the projector is warming up. It takes longer in LED projectors and bulb projectors – the bulbs can’t go from off to full blast immediately. 

As such, they need a “warm up” period in order to be able to adequately project. This isn’t apparent in laser projectors as the laser can go from on to full blast without a hitch. Furthermore, warm up isn’t something to worry about or have concern over.

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