Even though it is such a basics in graphic design, there still has been a massive confusion around the DPI. Common questions are: What is the minimum DPI for printing photo and poster? How to determine the DPI while designing a graphic for publication? And how large can the photo be printed? This article will offer you the answers and clarify them so that you can have your own printing solution for any of your publication. So in this post we will know how to set the minimum DPI for printing.
What is DPI?
DPI stands for Dots Per Inch, and it is a unit of measurements for image resolution. DPI is used in desktop printers and scanners.
The meaning of converting 70 DPI or any “less than 300 DPI” to 300 DPI is that we are trying to cram more pixels into each inch. Understand this is very important to set the minimum DPI for printing. Obviously, the higher the number of pixels we can cram into that same inch of paper, the higher the quality the image is going to be on the final output, So, that’s why we have higher resolution and lower resolution or higher-quality and lower-quality images.
What affects the printing quality?
Best results are achieved when images are taken with the quality settings and highest image resolution that the camera can provide. For any image, you can determine how large it should be printed using the pixel density or the PPI. Inches are used to simplify calculations. Image resolution completely is a vital factor to set the minimum DPI for printing.
Printer’s output resolution
While digital images are made up of discrete blocks of color known as pixels, the images printed by inkjet printers are produced by placing tiny dots of ink onto the paper. Photo printers typically use between 6 and 10 different hues and tones to reproduce colors. Many ink dots are required to generate the tone and hue that corresponds to each pixel in the photo.
All printer drivers have raster image processor (RIP) software that demonstrates the size and placement of the ink dots on the output image. The printer driver is in charge of how the dots are laid down onto the printing material and control the resolution it will handle to be compatible with the output abilities of the printer’s print head.
If the image’s PPI resolution sent to the printer is too low, it is interpolated up, and there’s a possibility of interpolation artifacts (banding, moiré, and jagged edges). If the image’s PPI resolution is too high, the image will be downsampled, and image data is lost. For the optimum effect, there should be a correspondence between image PPI and the printer’s DPI setting.
Even though human vision is good, but it has its limitations. The average human eye cannot recognize the differences in resolution at output resolutions greater than 350 pixels/inch with close examination.
Yet, as you move back from the print, you will not be able to see the complete fine details, even in good lighting conditions. As a result, graphic designers usually dwindle the output resolution without having an apparent declination in image quality. This is the final factor that affect the setting of minimum DPI for printing.
What is the standard DPI for printing?
A regular photo inkjet printer offers a linear resolution of up to 1440 DPI. In other words, it can lay down 1440 droplets of ink in each linear inch of the printing material. The dots are arranged into cells to recreate the continuous tones in the photograph. Larger cells usually have more tones while smaller cells give greater details. Thus, there’s a trade-off between output resolution and color handling.
A typical rule of thumb stated that the optimal image resolution for printing most common output sizes should be 300 PPI. According to this rule, you can divide the photo resolution by 300 will tell you approximately how big you should make prints at A4 sizes and snapshot.
Lower 300 DPI resolution begins to fall off although, it depends on the printer, you might not see much difference in print quality between 250 DPI and 300 DPI with your eyes. At typical viewing distances, the differences will probably be invisible so we’ll classify all resolutions above 250 dpi as excellent.
If you are using an 8-megapixel camera with a 3:2 ratio, you can obtain excellent cutting-edge A4 prints with 300 DPI. To achieve this result, you divide the image’longer side in pixels (3504) by the length of the A4 paper sheet in inches (11.69). The result is 299.74 DPI, which is close to 300 DPI.
The similar calculation can be used on higher-resolution images. It shows that all cameras are capable of producing excellent quality at output sizes of A4 and smaller. Actually, when printing at snapshot size, images from files that are larger than 1800 x 1200 pixels need to be interpolated down.
How to enlarge the image for printing?
Professional photographers usually make prints of their best images with poster size. The same calculations can be applied to predict maximum output quality, with consideration to how different-sized prints are viewed from the average distances. Enlarge the image can affect the default minimum DPI for printing.
Meanwhile, many photographers like to make larger prints with a white border. The width of this border propionate to the paper size depends on individual gout and preference. However, in most cases, the white border is at least an inch on each side of the paper sheet.
With the output resolutions at 180 DPI and below, there will be a discernible loss of properties, especially in highlights, and noise will be manifest in areas having shadowed tones. This level is rated as poor print quality.
From 180 to 250 DPI there’s a shaded area we have classified as good. Moving to the scale’s lower scale, publications made with resolutions between 180 and 200 DPI may include some artifacts in detailed areas but they might not be noticeable in big prints at regular viewing distances.
Above 250 DPI, images will be good enough to resist scrutiny at normal viewing distances. So what is the best viewing range for enlarged prints? In general, people naturally take two standpoints, the first at a distance where they can pleasantly contemplate the whole image, and the second closer in where they can observe details. The distances vary from person to person, but most people stand farther away from larger pictures and closer to smaller ones.
To put it in a nutshell, there’s a trade-off between print resolution and viewing distance. By manipulating some simple calculations, you can determine the optimum DPI for your printing. Hope this article could help you to produce the most good-looking publications with the understand of minimum DPI for printing. Thank you for reading.