Can You Use a Projector on a Dark Wall

If you try to imagine a projector screen in a movie theater, you are probably imagining a large, flat white surface.  In reality, projector screens aren’t white.  In fact, they are much darker than this.

So this begs the question, Can you use a projector on a dark wall?  The answer is, absolutely yes.

This article will explain why dark walls and colors are sometimes the best colors to choose when deciding on your ultimate home theater or office wall for presentations.  This seems counterintuitive to the human brain, but let TechChiller explain why.

What is the best color to paint a wall for a projector?

So you are probably thinking that white is the best color to paint a wall to project onto?  You’d actually be wrong.

White would certainly ensure that the colors projected from a projector were true to the colors that were presented to you on the wall.  This is because white reflects light extremely well as it doesn’t absorb the colors.

Therefore, the colors will be high fidelity.

This highly reflective property of the color white is also why it isn’t great for projecting on walls in some circumstances.

If your environment, whether it be your home theater or a conference room at work, contains a lot of ambient light, then your projector will struggle to display a perfect image.

This is because the ambient light created by nearby external windows, room lighting, etc, won’t be absorbed by the wall but instead will be reflected back to the viewer.

This causes the image to become washed out and faded, as the image will be lower in contrast and the blacks won’t be as black as they should be.

The darker the color paint on the wall, the less reflective the wall will become.  This is because dark colors absorb light.

Black paint absorbs almost all ambient light which is why black is black. However, if a wall was painted completely black, the projector itself would struggle for its image to be reflected back to the viewer.

Therefore, there is a happy medium to be reached with how dark you should paint your wall for the purpose of projecting.

That happy medium is the color gray.

Gray has some of the light absorbent properties of a dark color which increases the contrast in colors and isn’t as reflective as a white wall and therefore is less susceptible to washed-out colors caused by white walls.

The properties of these darker and lighter colors are what is called gain.  Gain is the level of reflectivity of a surface.  A low gain value is more reflective than a high gain surface.  The lower the gain value, the more susceptible the surface is to ambient lighting.

Luckily for us, there are specialist paints available that have been specifically designed to be painted onto walls and surfaces for the sole purpose of projecting images.  As you would expect, these specialist paints are called screen paint.

Can you use a projector on a black sheet?

You can definitely use a projector on a black sheet.  As long as the black sheet isn’t ultra smooth like a silk sheet and is instead more like a think cotton sheet, it will have very light absorbent properties.

These light absorbent properties will mean that the projector will not have to compete with any ambient light in the surrounding area caused by light sources such as external windows or room lighting.

This means that the picture will have a high contrast of colors.

There is a trade off for this low reflective property gained by using a black sheet.  The trade-off is a fuzzy image with colors that don’t match.

This is caused by the black color.  Black absorbs light which is why black is black.  If your projector has a low amount of lumens and therefore brightness, then it is going to be hard for it to be bright enough to reflect enough light back to the viewer.

Another determining factor for this would be how far away the projector is from the black sheet.  The further the projector is away from the screen, the lower the amount of lux and therefore lumens projected onto the sheet or wall.

A better color choice for the sheet would be gray.  Gray would be the happy compromise between the ultra-reflective properties of white as well as the ultra-absorbent properties of black.

Is projector paint as good as a screen?

In most situations, a projector screen is a better solution than using projector paint on a wall or other surface.  The reasons for this will be explored further.  On the other hand, there are occasions when it makes sense to use projector paint instead of a projector screen.  Again, these will be explained below.

So in what situations would a projector screen be a better solution than projector paint?

Well, projector screens offer all-round solid performance when projecting images to them as this was their sole purpose when being designed.  They all come with a good surface color making, that strike the correct balance of light absorbance and reflectivity.

Also, they offer a smooth surface for which to project onto.  If you are trying to project directly onto a wall painted with specialist projector paint, if the wall surface has any minor cracks or is slightly uneven, then these irregularities will show up in the image.  They might only be minor but they will be there.

A projector screen on the other hand will be flat and smooth.

However, there are benefits to using projector paint on walls and surfaces rather than projector screens.  

For instance, if you require a large surface by which to project onto, painting a surface with projector paint is a much cheaper way of achieving fantastic without breaking the bank.

There are also aesthetic reasons for this too.  Although projector screens can be rolled away into the unit and therefore become less obvious to the eye, they can still be seen and they can look unsightly.

A wall painted with projector paint on the other hand will just look like any other wall and you won’t notice it at all.

Which projector paint is best for a wall?

Below are two of the most highly recommended projector paints available online.

S1 Screen Plus – Paint on Screen

The S1 Screen Plus projector paint is Paint on Screen’s mid-range product when it comes to gain.

Gain is the level of reflectivity of a surface.  A low gain value is more reflective than a high gain surface.  The lower the gain value, the more susceptible the surface is to ambient lighting.

The S1 Screen Plus product has a gain value of 1.4 which means that it will be ideal for moderate levels of ambient lighting within the environment.

The S1 paint will support projector resolutions up to 4K.

The 3.78L tin will easily cover an area 170 square feet in area which is approximately 240” in diameter.  Remember it will take two coats of paint to provide a quality projector surface.

Although the price of the paint is expensive as tins of paint go, this solution is far cheaper than the cost of purchasing a 240” projector screen.

If you need a higher contrast surface with a gain value of 2 then choose Paint on Screen’s S1 Ultimate Contrast paint which essentially is a darker gray matt finish.

Ultra White High Definition Screen Paint – Screen Paint Supply

Ultra White High Definition Screen Paint made by Screen Paint Supply is a product with a reported high gain.  Although Screen Paint Supply doesn’t state exactly what level of gain is achieved with this paint, we believe that it will be approximately 1.0 or 1.2.

This is because it is an ultra white paint.  Therefore it will be susceptible to ambient light in the environment when compared to the darker S1 Screen Plus paint, mentioned above.  The S1 Screen Plus paint is gray in color.

As long as the room that you are projecting in is free from high levels of ambient light when you are due to use the projector, this paint should be fine.

The 1 gallon (3.78L) tin will easily cover an area 170 square feet in area which is approximately 240” in diameter.  Remember it will take two coats of paint to provide a quality projector surface.

The Ultra White High Definition Screen Paint will provide 4K resolutions is painted onto a smooth, flat surface and of course, as long as your projector can support up to 4K video output.  The ultra-white finished will really make the colors of the image pop, which is great for home theater enthusiasts.

Considerations for Projecting to Walls

Although it is absolutely possible as well as desirable to project onto a dark wall, there are some considerations to make before proceeding.

Prepare the wall for painting

Before applying any paint to the wall, remember to prepare the surface first.

A smoother wall will yield a much sharper image.  Therefore, ensure that any cracks in the wall are filled with a very fine waller filler.  Using as fine a wall filler will make it easier to sand the surface down whilst providing an ultra-smooth finish.

If you are painting your projector paint on a wall that has already been painted, prepare the area to be painted with a light sanding and primer coat of paint.

Ambient Light Levels and Gain

Before choosing which projector paint to buy, first, check the light levels in the room.  If your room is full of ambient light (from nearby windows or lighting), then you are better off choosing paint with a high gain whereas if your room won’t have much ambient light when you are projecting then you can choose a paint with a lower gain level.

Gain is the level of reflectivity of a surface.  A low gain value is more reflective than a high gain surface.  The lower the gain value, the more susceptible the surface is to ambient lighting.

It’s sometimes difficult to know for sure how well the projector paint you choose to buy will perform until you try it.

The good news is that if your wall is too dark or too light then this can be easily repainted with paint with a different gain level.

Number of coats of paint

To achieve the optimum level of image quality from your projector, you will need to apply at least two coats of paint to ensure that the wall is uniform with the color of paint you have chosen.

Sometimes walls dry differently in specific patches so a second coat will resolve any differences in tone or color.