One of the most important factors to consider when printing is DPI, or dots per inch. Basically, DPI is a measure of special printing dot density which consists of the number of individual dots that can be placed in a line within the span of 1 inch. When choosing a resolution, it’s all about determining the point at which you can no longer see the dots in an image. The more dots, the higher the quality of print.
It’s also helpful to point out that many resources, including the Android developer guide, use the term pixels per inch, or PPI, interchangeably with DPI. While these terms are similar in nature, PPI is technically the term used for monitors. (Monitors have pixels, not dots.) When discussing printing, DPI is the correct term and it can make a big difference in the sharpness of your printed work.
So with that brief overview, the question remains: What DPI should I use for my particular print job? As you may have guessed, the correct answer is, it depends. Below are some tips to consider when deciding on a DPI, as well as some suggestions for specific printing designs.
It’s (Mostly) About Viewing Distance
As mentioned above, the main focus (no pun intended) when choosing the correct DPI centers on the point at which you can no longer see the individual dots on a page. While the method of printing and the material may have a slight impact on the resolution, the viewing distance can be the difference between 300dpi and 1dpi. If you think about it, that makes sense.
Consider looking at a billboard on the side of the road. It’s rarely viewed closely, so a resolution of 20-50dpi is probably sufficient. However, when viewing a printed image on a menu for example, you’ll want a higher DPI so the print doesn’t look grainy or blurred. The key when considering DPI is to consider how far your viewer will be.
Choosing the Correct Material and Methods
In addition to contemplating the audiences viewing distance of an image, the printing method and material also have an impact when determining the correct DPI. The method and material will affect how sharp an image will be; the higher DPI used, the sharper the image. For example, the Print Handbook is printed using a stochastic screen which produces a finer detail than a halftone screen. The different material will produce a print that looks different when using 300dpi and 400dpi.
Conversely, there are other instances when the limiting factor is the paper/material or printing method and as a result, there is no need for 300dpi. One such example of this would be printing on coated vs. uncoated paper. Coated paper tends to hold detail much better than uncoated paper, and because of this limiting factor, you can likely get away with using 200-250dpi on uncoated paper whereas the same DPI would not be suitable for print on coated paper.
Choosing the correct DPI can indeed be the difference between a good and a great print. It is important to understand what DPI is and which DPI should be used for your specific print job. It’s also important to consider the distance at which the print will be viewed, as well as the print material and methods used. However, given all this, it’s typically better to err on the side of a larger DPI. You can rarely make the mistake of having too high a resolution. But it is very easy to use a low DPI and have your final result come out pixelated. In the end, go for too much detail as opposed to not enough.
Contact Pel Hughes if you have more questions!