Last updated on September 28th, 2022 at 01:00 pm
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You’ve heard the word mentioned in your projector sewing groups, but what exactly is throw or throw ratio? Throw is the image size your projector creates relative to its distance from the image.
Most projector specs will not state the throw ratio. Rather, they will give you a diagonal screen size and distance from the projector.
For a good throw ratio you want a large screen size in a smaller distance. Remember you are unlikely to have more than 6 feet from the ceiling to your cutting table. The larger the image at six feet, the better the projection size for sewing.
You will want a projection size at least the size of your cutting mat and pattern pieces. If your pattern piece is larger than your projector size, then you will have to make some adjustments when cutting your patterns.
Short throw means the projector can create a large picture in a short distance. Projectors with the lowest throw distance are classified as Ultra Short Throw projectors. These projectors are typically more expensive than other projectors, but can often be found second hand for a decent price.
Other projectors have varying throw, but are typically stated as a diagonal screen size and a certain number of feet.
Calculate Throw Ratio
- You can calculate your ideal throw ratio for your projector set up using this formula.
Throw Ratio = Throw Distance / Image Width
Example: If you want your cutting layout to be 3 ft wide and you have at least 4 feet distance from the projector to your sewing table. Your throw ratio would need to be at least 4ft / 3ft or 1.3 ft.
Look for a projector that has less than or equal to this throw ratio to work for your set up.
- If you know the throw ratio of your projector, then you can calculate the image width by arranging the formula.
Image Width = Throw distance / Throw Ratio
Example: If your projector has a throw ratio of 0.8 ft and you have 4 ft from your projector to sewing table, then your image will be 0.8 / 4 ft. or 3.2 ft wide.This translates into a cutting image size of about 38 inches.
- To calculate your desired throw distance, use this formula.
Throw Distance = Throw Ratio x Image Width
Example: If you have a projector with a 1.2 ft throw ratio. Then, 1.2 ft x 3.2 ft (desired imagewidth) = 3.84 feet throw distance. This means you need at least 3.84 feet from your projector to sewing surface to create an image this size.
Conclusion:
If you are looking for the largest possible cutting area, keep throw in mind. Projectors with a smaller throw ratio will give you a larger screen image in less distance. If you have a projector with a large throw ratio, you will need more distance between your projector and cutting surface.
