The benefits of short throw projectors include:

Less Shadows and Glare: Because the projector is closer to the screen, there is less risk of shadows cast by people standing in front of the projector, and less risk of glare for the presenter or viewers.

Less Space Required: Short throw projectors can project large images from a relatively short distance, requiring less space between the projector and the screen. This is especially useful in environments with limited space.

Flexible Installation: Due to their short projection distance, short throw projectors can be more easily installed in tight spaces and can also simplify ceiling mounting.

Less Light Loss: As the projector's light travels a shorter distance before reaching the screen, there's generally less light loss, resulting in brighter images.

Less Eye Strain: Viewers don't need to turn around as much to see the entire projection image, which can help reduce eye strain.

High Brightness and Durability: Laser projectors generally provide higher brightness and maintain this brightness over a longer period compared to traditional lamp-based projectors. This is especially useful in well-lit classrooms.

Extended Lifespan: Laser technology has a significantly longer lifespan than conventional lamps, meaning the projector requires less frequent maintenance or lamp replacement. This reduces overall ownership costs in the long term.

Less Maintenance: Laser projectors don't have a lamp that needs regular replacement, making maintenance simpler and less time-consuming.

Faster Startup Time: Laser projectors typically have a faster startup time compared to traditional lamp-based projectors, saving time in waiting for the projector to become operational.

Consistent Color Performance: Laser technology ensures consistent color performance throughout the projector's lifespan, which is particularly important for displaying educational content with color accuracy.

Environmentally Friendly: Laser projectors generally consume less energy and lack a fragile lamp to replace, making them a more environmentally friendly option.

Silence: Laser projectors are generally quieter in operation than projectors with traditional lamps, creating a quieter and less distracting learning environment.

Flexible Placement: Laser projectors often offer flexible placement options and can be easier to mount on ceilings or walls.

Reduced Heat Production: Laser technology generates less heat than traditional lamps, reducing the risk of overheating and the need for additional cooling.

Fewer Interruptions: With reduced maintenance needs and consistent projection performance, there's less risk of unexpected interruptions during lessons.

The throw ratio is typically expressed as a ratio, for example, "1.5:1". This means that for every unit of screen width, the projector needs to be placed at a distance of 1.5 units. For instance, if you want to project an image with a width of 6 feet and the throw ratio is 1.5:1, the projector should be placed at a distance of 9 feet from the screen.

There are different types of throw ratios, including:

Short Throw Ratio: These ratios are usually smaller than 1 and indicate projectors that can project a large image from a short distance to the screen.

Standard Throw Ratio: These ratios are around 1 and indicate that the distance to the screen is approximately equal to the width of the projected image.

Long Throw Ratio: These ratios are greater than 1 and suggest that the projector needs to be placed farther from the screen to project a large image.

The choice between projecting on a wall or on a projection screen depends on various factors, including image quality, the environment, intended use, and personal preferences. Here are some considerations to help you make a decision:

Projecting on the Wall:

Advantages:

Easy Accessibility: You don't need an extra screen, as any white wall can serve as a projection surface.
Cost Savings: No cost associated with purchasing a projection screen.
Immediate Availability: You can start projecting immediately without any installation.
Disadvantages:

Image Quality: A white wall can impact image quality, especially in terms of color rendering, contrast, and reflections.
Irregularities: Walls may have irregularities, imperfections, and texture that can disrupt the image.
Light Absorption: White walls can absorb light, leading to a less bright image.
Projecting on a Projection Screen - Projection sur un Écran de Projection:

Advantages:

Better Image Quality: Projection screens are designed to offer optimal image quality, with improved color reproduction, contrast, and brightness.
Reduced Reflections: Projection screens reduce reflections and provide a cleaner image.
Uniform Surface: Projection screens offer a uniform surface without irregularities.
Disadvantages:

Additional Costs: Purchasing a projection screen represents an extra cost.
Installation: The projection screen needs to be properly installed and positioned.
The choice between a wall and a projection screen depends on your priorities. If image quality and an optimal projection experience are important to you, a projection screen might be a better choice. However, if cost savings and simplicity are priorities, projecting on a wall can be a suitable option.

It's also important to note that there are special paints and coatings you can apply to a wall to enhance projection quality if you still choose to project on a wall.