Relationship between dpi and lpi

The Print Guide: Image resolution for printing - LPI vs DPI a.k.a. LPI vs PPI a.k.a. LPI vs SPI

relationship between dpi and lpi

We use unit Dot per Inch (DPI) for desiging and when we go on Out put a unit uses Line per Inch (LPI). Is there any relation between these units. DPI vs LPI. Dots Per Inch (also known as DPI) is literally a measurement of the maximum number of dots any printer has access to per inch. There is a lot of confusion on the proper terms for LPI, DPI and PPI. Some of the confusion comes from interchanging the terms by graphic.

Higher quality printing uses finer screen values. Newsprint may use lpi; web offset lpi printed from rolls of paper, like consumer magazines ; standard sheetfed offset lpi printed from "lifts" of trimmed sheets of paper ; fine quality art book, etc. Finer dot patterns can be used under ideal conditions.

Otherwise they will tend to "plug" block up or skip. Silkscreening and rubberplate printing for printing directly on uncoated corrugated boxes may use very coarse values with very visible dot patterns. In addition, there are stochastic screens that use a random pattern to create a less visible dot with offset pinting. This allows for a bit of "wiggle room" if you have to make a small or last-minute increase in image size without scanning again.

You can certainly use images that are sampled at somewhat higher rates.

DPI, PPI or LPI -- what's the difference? | Adobe Community

But there is no benefit. It won't give you more detail in your printed image due to the limiting resolution of the halftone screen. Vector-based images, such as those created in Illustrator, or most editable fonts, are based upon mathematical curves, not pixels.

As such, they are infinitely scalable, and will be absolutely sharp at almost any size. But when they are finally output, these vectors are still first converted to to the finite elements of the desktop printer or commercial press, just as pixel-based images are. Exceptions include "solid" ink color unscreened, maximum ink density in offset printing, such as black type or linework, which have no dot pattern.

DPI This is the usual specification for resolution of output devices, such as desktop printers, film recorders, RIPs imagesettersand again computer monitors.

PPI vs. DPI: what's the difference?

For computer monitors and film recorders, there is a 1: In most other cases, especially with today's typical desktop inkjet or laser printers, there is a vast difference between dpi and ppi. At an inkjet printer's, say, dpi resolution, many micro dots of ink are used to build one image pixel.

relationship between dpi and lpi

Let's do the math: Dividing, we see that 9. Even so, you often cannot tell the difference in print quality betweeen a dpi print and one made at dpi. But, rescanning or recreating your pixel-based reflective art image at ppi is not a practical option for enhancing detail.

First, you will end up with an unwieldy file, over 90 times larger than necessary.


Secondly, the high native dpi of your inkjet is to give you smoother, more photo-like tonal transitions and perhaps crisper type and fine rules with your ppi images. It won't give you any usable increase in image detail for higher resolution images.

relationship between dpi and lpi

What you need to understand: In the printing process, all the physical pixels that composed the image on screen are translated into little squares of different hues on paper. And how do you increase or decrease print-out size in this way? Suppose you have a x pixel image. If you set the PPI to 10, this is going to make the print out relatively large: If you set the PPI tothis is going to make the print out relatively small: Think of the PPI input as a way to adjust the physical size — not the resolution — of the eventual print-out.

Decreasing the PPI, thus increasing the size of the printout, may seem to produce a lower quality image because the pixels are larger and more visible.

relationship between dpi and lpi

But remember, this is only a relative gauge of quality; if you were to stand further away, the image would appear as clear as it did before. So the way to increase the resolution of an image is to produce an image with more pixels, not increase the PPI. Friction NYC via flickr Looking at this billboard close up, the pixelation is obvious so are dots, which we will discuss in a minute.

Difference Between DPI and LPI

But at the distance from which most passersby will see it, it will look crystal clear. Nick Sherman via flickr Printers do not reproduce an image by tiling pixel squares directly on top of one another. Rather, they reproduce an image by spitting out tiny dots consisting of a mix of four colors, Cyan, Magenta, Yellow and Key blackwhich combine to create a range of hues by the subtractive color model.

There is bound to be some space between these dots, and this is what DPI measures: Newspapers often use 85dpi and the effect is clear: Typical dot matrix printers are capable for 60 — 90dpi, inkjet printers — dpi, and laser printers — 1,dpi.

DPI is just a technical aspect of an individual printer, like the pixel resolution of your computer monitor.