Basic Resolution Explanation for Beginners

02/07/2012  | by: Shaun Cleary

The whole idea of resolution and graphics size is quite a complex one and can really cause beginners in printing to fall down. If you’re not familiar with desktop publishing you can end up in a bit of tizzy.

However, it’s not hard to grasp the basics and get a good foundation.

 
Resolution

Resolution small.jpg

Resolution as you may know is the number of dots of ink, or on a computer screen – pixels in an area. If you know anything about printing, you may be familiar with DPI or dots per inch – this is often a commonly used term when purchasing a new home printer and is a measure of resoltuon.

There are also these measurements – each of which is different.

• PPI – Pixels per inch
• SPI – Samples per Inch
• LPI – Lines per Inch

These are all differently measures of resolution and are often used incorrectly. So, to ease confusion, we’ll just focus on DPI or dots and output from printers.

 

Dots – Some Basic Information

dots per inch

When printed on paper or on screen a picture is made up of lots of little dots.

There are of course coloured and black dots. In black and white images the closeness of black dots creates different shades of grey.

The more dots used the higher the resolution and so the better the quality of the image. Dots are measured in a square inch.

 
Understanding print vs. on-screen

Printers generally have a higher resolutions than computer screens and are richer in their images, Most screens can only display a maximum of 96 dots in the case of Windows and 72 dots in the case of Mac. However, printers can print far more. For instance a 600DPI laser printer will produce 600 dots in an inch.

If you display a 600 DPI image on a Windows run screen it is only possible to show 96DPI at the most. This means the file size will be significantly larger than a 96DPI image made just for the web and so wastes file size but doesn’t improve on the quality of the on-screen image. An image on screen is only as good as the maximum amount of DPI the screen can display however on print this is different (which is why there is a difference between made for print images (300dpi) and images on websites ect (72dpi) which is why most images taken from the internet do not print at a decent quality.

Scanned images: (300dpi) image scanned on a 180DPI scanner will only be a 180DPI image on screen, even if the original print was 300DPI.

Another thing to note with quality is that if you print from a website with 72DPI images to a 300DPI home printer, it will never look as good in print as it did on screen. This is because the printer won’t have enough information on the dots to create a high quality image. However, modern printers can really help increase the quality of low resolution sources to make them still look quite good.

It’s all quite confusing, but hopefully you have a better understanding for your printing needs.

     Comments

Find Us On Facebook