Why does the print shop ask for a “High Resolution” image and what does that mean?

Many clients are confused by the resolution question. They see a logo on their website and believe the same logo file on the website can be used to print their letterhead. Here’s background on why this isn’t true.

A computer monitor renders an image using resolution – how many dots per square inch (dpi) it takes to fill an image to make it clear to see. The beauty of websites is that they require very low resolution in order to show a graphic cleanly – only 72 dots per square inch (dpi).  72 dpi is the lowest resolution used.

Printed material, however, requires a much higher resolution in order to look clean and sharp – a minimum of 300 dpi. This is because ink is being applied to paper. 72 dots per square inch would make the image fuzzy and grainy or “pixilated”.

Example:

300 dpi                                                                                  72 dpi

A high resolution image can easily be converted to a website resolution image but a website resolution image cannot be converted to a higher resolution. It’s simple math, really – we can take 300 dots and reduce it to 72 dots. However, we cannot start with 72 dots and make them grow to 300 and look the same. That is why images get so fuzzy. The dots are doing 3 times the work they are supposed to. They are literally spreading themselves too thin.

Some good rules of thumb:

• Request a high resolution image from your graphic designer for all logos and graphics
• High resolution images are larger files than low resolution images – making high resolution images more flexible to manipulate for the graphic designer and the printer
• The best file types are (.eps), (.tiff) for high resolution images