Resolution

Understanding resolution
<span style="background-attachment: initial; background-clip: initial; background-color: #ffffff; background-image: initial; background-origin: initial; border-top-color: #ff3300; border-top-style: solid; border-top-width: 3px; display: block; font-family: inherit; font-size: 12px; font-style: inherit; font-weight: inherit; margin-bottom: 1.5em; margin-left: auto; margin-right: auto; margin-top: 0px; padding-bottom: 0px; padding-left: 15px; padding-right: 15px; padding-top: 0px; position: relative; text-align: left; text-decoration: inherit; width: 930px;">  ==**dpi is NOT THE SAME as ppi !!** == Even though "dots per inch" (dpi) and "pixels per inch" (ppi) are used interchangeably by many, they are not the same thing. Traditional printing methods use patterns of dots to render photographic images on a printed page. While**pixels** on a monitor are square and in contact with the adjacent pixels, **printed dots** have space between them to make white, or no space between them to make black. Color photographs are printed using four inks, Cyan, Magenta, Yellow, and Black (CMYK), and four separate dot patterns, one for each ink. Dots per inch (dpi) refers to printed dots and the space between them, while pixels per inch (ppi) refers to the square pixels in a digital image. Keep in mind that many companies will ask for images at 300dpi when they really mean 300ppi.

==**Why do I need 300ppi for a "photo quality" image?** == First, some background information is necessary. A digital image is what it is. It is however many pixels wide by however many pixels tall. If you divide each dimension by 300, you will have the size of the image at 300ppi. Now think about 300 pixels in an inch of space. Each pixel could be black, white, or any other color, but they are all next to each other with no spaces between them. When a digital image is prepared for reproduction on a printing press, pixels are converted to dots. Dots have spaces between them. 300 pixels become 150 dots and spaces, so 300ppi becomes roughly 150dpi. 150dpi is the accepted standard for printing photographic quality images.

Printers usually refer to the number of rows or lines per inch (LPI). 150 lines per inch is simply 150 rows of 150 dots per inch. 150 LPI and 133 LPI have long been the established standards for the best quality reproduction of photographs in books and magazines. Newspapers traditionally use 85 LPI for photographs and detail is lost because the dots are plainly visible.

==**Viewing distance changes everything!** == Everything is relative to viewing distance. 150dpi (or 300ppi) is accepted as photo quality because the average person cannot see the "dots" at a few inches away. A real photograph made from film in a darkroom has no dots or pixels and therefore is the standard by which "photo quality" is judged. When you move the viewer further away from the printed material, lower dpi is acceptable. A huge billboard might be printed at only 40dpi but no one notices because everyone is 50 yards away from it.

==**I always see "72dpi". Where is that used?** == 72dpi should really be 72ppi because most likely, it has nothing to do with printing. Most of the time, 72dpi refers to output on a computer monitor. A 72 pixel by 72 pixel image should take up about one inch of space on the screen. This of course depends on the size of the monitor and what resolution it is set to. When creating images for web sites, we've found it's best to determine what screen resolutions will be used most often by that site's visitors, instead of thinking about inches at all.

==**Megapixels vs. Maximum Print Size Chart** == 
 * **Megapixels** || **Pixel Resolution*** || **Print Size @ 300ppi** || **Print size @ 200ppi** || **Print size @ 150ppi**** ||
 * ==**3** == || 2048 x 1536 || 6.82" x 5.12" || 10.24" x 7.68" || 13.65" x 10.24" ||
 * ==**4** == || 2464 x 1632 || 8.21" x 5.44" || 12.32" x 8.16" || 16.42" x 10.88" ||
 * ==**6** == || 3008 x 2000 || 10.02" x 6.67" || 15.04" x 10.00" || 20.05" x 13.34" ||
 * ==**8** == || 3264 x 2448 || 10.88" x 8.16" || 16.32" x 12.24" || 21.76" x 16.32" ||
 * ==**10** == || 3872 x 2592 || 12.91" x 8.64" || 19.36" x 12.96" || 25.81" x 17.28" ||
 * ==<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px; letter-spacing: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px;">**12** == || 4290 x 2800 || 14.30" x 9.34" || 21.45" x 14.00" || 28.60" x 18.67" ||
 * ==<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 16px; letter-spacing: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px;">**16** == || 4920 x 3264 || 16.40" x 10.88" || 24.60" x 16.32" || 32.80" x 21.76" ||
 * 35mm film, scanned || 5380 x 3620 || 17.93" x 12.06" || 26.90" x 18.10" || 35.87" x 24.13" ||
 * Typical Resolution. Actual pixel dimensions vary from camera to camera.


 * At 150ppi, printed images will have visible pixels and details will look "fuzzy".

<span style="display: block; font-family: inherit; font-size: 12px; font-style: inherit; font-weight: inherit; margin: 0px; padding: 0px; position: relative; text-decoration: inherit; zoom: 1;"><span style="display: block; font-family: inherit; font-size: 12px; font-style: inherit; font-weight: inherit; margin-bottom: 1.5em; margin-left: 0px; margin-right: 351px; margin-top: 1.5em; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; position: static; text-decoration: inherit; width: 930px;"><span style="display: block; font-family: arial,helvetica,sans-serif; font-size: 13px; line-height: 19px;">Inkjet printer DPI Today's inkjet printers have three standard output settings:

<span style="display: block; font-family: inherit; font-size: 12px; font-style: inherit; font-weight: inherit; margin-bottom: 1.5em; margin-left: 0px; margin-right: 351px; margin-top: 1.5em; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; position: static; text-decoration: inherit; width: 930px;"> <span style="font-family: inherit; font-size: 12px; font-style: inherit; font-weight: inherit; margin-bottom: 1.5em; margin-left: 0px; margin-right: 0px; margin-top: 1.5em; padding: 0px; text-decoration: inherit;">You might also have a draft or economy setting, but you should never use this setting for printing images. It's primarily used for printing text and rough drafts. <span style="display: block; font-family: inherit; font-size: 12px; font-style: inherit; font-weight: inherit; margin-bottom: 1.5em; margin-left: 0px; margin-right: 0px; margin-top: 1.5em; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; position: static; text-decoration: inherit; width: 930px;"> A popular myth is that it's necessary to scan an image at the same resolution that you will be using to print. In the case of color and grayscale images, this only results in excessive file sizes. At one time, a good general rule for inkjet printing was that you needed half to one-third of the PPI of the printer's DPI setting that you intend to use. So if you're using your printer's "normal" setting (300 dpi), your image needed to have at least 150 ppi. When using the higher quality printer settings (720 dpi and up), you can bring the PPI down to about 1/3 of the output resolution. That would be 240 ppi for your printer's 720 dpi setting. Cameras and megapixels:
 * <span style="display: block; font-family: inherit; font-size: 12px; font-style: inherit; font-weight: inherit; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; text-align: right; text-decoration: inherit;">normal: || 300 x 300 or 320 x 320 dpi ||
 * <span style="display: block; font-family: inherit; font-size: 12px; font-style: inherit; font-weight: inherit; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; text-align: right; text-decoration: inherit;">high quality: || 600 x 600 or 720 x 720 dpi, 1440 x 720 ||
 * <span style="display: block; font-family: inherit; font-size: 12px; font-style: inherit; font-weight: inherit; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; padding-bottom: 0px; padding-left: 0px; padding-right: 0px; padding-top: 0px; text-align: right; text-decoration: inherit;">photo quality: || 1200 x 1200, 1440 x 1440 dpi, 2880 x 1440 and up ||


 * **Megapixels** || **Print Size (inches)** ||
 * 2.0 || 4 x 6 [standard] ||
 * 3.0 || 5 x 7 ||
 * 4.0 || 8 x 10 ||
 * 5.0 || 9 x 12 ||
 * 6.0 || 11 x 14 ||
 * 8.0 || 12 x 16 ||

How did we determine this?

Since image sizes are described in pixels and photographic prints in inches, you have to convert from pixels to inches. To do so, you divide the image's dimension in pixels by the resolution of the device in pixels per inch (ppi).

For comparison purposes, monitors use an average of 72 ppi to display text and images, ink-jet printers range up to 1700 dpi or so, and commercial typesetting machines range between 1,000 and 2,400 dpi.

For example, to convert the dimensions for a 1500 x 1200 image being printed at //**300**// ppi you divide as follows:

**Height: 1200 pixels ÷ 300 ppi = 4"**
The result is a 5" x 4" print. However, if the output device prints **//600//** ppi, the result changes to a 2.5" x 2" print as follows:

**Height: 1200 pixels ÷ 600 ppi = 2"**
<span style="font-family: Verdana,Arial,Helvetica,sans-serif; line-height: 16px;">Printer resolution is measured in ink dots per inch, also known as dpi. <span style="font-family: Verdana,Arial,Helvetica,sans-serif; line-height: 16px;">Generally, the more dots per inch, the finer the printed output you’ll get. <span style="font-family: Verdana,Arial,Helvetica,sans-serif; line-height: 16px;">Most inkjet printers have a resolution of approximately 720 to 2880 dpi.

<span style="font-family: Verdana,Arial,Helvetica,sans-serif; line-height: 16px;">Printer resolution is different from, but related to image resolution. <span style="font-family: Verdana,Arial,Helvetica,sans-serif; line-height: 16px;">To print a high quality photo on an inkjet printer, an image resolution of at least 220 ppi should provide good results.

Basically the term DPI refers to the resolution of the printing device, where PPI refers to the resolution of the image itself. . How can you remember this? //Monitors display pixels, and printers produce dots.// Today's photo-quality ink jet printers have DPI resolution in the thousands (1200 to 4800dpi). They will give you acceptable quality photo prints of images with 140-200ppi resolution, and high quality prints of images with 200-300ppi resolution. Typically inkjet printers have three standard output settings: - normal: 300 x 300 or 320 x 320 dpi - high quality: 600 x 600 or 720 x 720 dpi, 1440 x 720 - photo quality: 1200 x 1200, 1440 x 1440 dpi, 2880 x 1440 and up You might also have a draft or economy setting for printing text and rough drafts.

At one time, a good general rule for inkjet printing was that you needed half to one-third of the PPI of the printer's DPI setting that you intend to use. So if you're using your printer's "normal" setting (300dpi), your image needed to have at least 150ppi. When using the higher quality printer settings (720dpi and up), you can bring the PPI down to about 1/3 of the output resolution. That would be 240ppi for your printer's 720dpi setting.
 * Summary:** You rarely need your image resolution to be higher than 240-300ppi for inkjet printing.

<span style="color: #000000; font-family: Verdana,arial; font-size: 10pt; margin-bottom: 0px; margin-left: 10px; margin-right: 0px; margin-top: 12px;">**How PPI Relates to Digital Cameras**
When you're printing images from a digital camera, you have a fixed number of pixels which is the maximum your camera is able to capture. Today's lower-priced cameras have an average maximum resolution of 2048 x 1536 pixels (3 Megapixels). The following chart shows the maximum print size for digital cameras based on the Megapixels of the camera. [A megapixel is 1 million pixels. It's an area measurement like square feet.] Most books and magazines require 300ppi for photo quality. For example, the chart shows that you can make a 5" x 7" photo quality print (300dpi) from a 3 Megapixel camera.

<span style="color: #000000; font-family: Verdana,arial; font-size: 10pt; margin-bottom: 0px; margin-left: 10px; margin-right: 0px; margin-top: 12px;">**Megapixels vs. Maximum Print Size Chart**
At 150ppi, printed images will have visible pixels and details will look "fuzzy". Using this table we can calculate that with 2048 x 1536 pixels we can either get a normal quality print at 8" x 10", a photo quality print at 5" x 7", or the highest photo quality print at 4" x 5" maximum. That's not a very big image for a photo quality print, so if you thought you'd be producing photo quality 8" x 10" prints with your $200 digital camera and inkjet printer, you're probably going to be somewhat disappointed. As you can see, there is a choice to be made as to whether you want to sacrifice printed size or image quality. If you plan to print many 8" x 10" (or larger) photo quality prints, you should have at least an 8 Megapixel camera. Print size and print quality are dependent on pixel resolution. Notice that as the print size doubles, the megapixels required increases geometrically. You can make nice 8" x 10" prints with a 6 or 8 Megapixel camera, but to make a true photo quality 16" x 20" print, you need between 24 and 30 Megapixels. Don't be fooled by manufacturers' claims that say you can make 16" x 20" prints from an 8 Megapixel camera. While you certainly can make a print that size, it will not be true photo quality and the image will not be as sharp.
 * ** Megapixels ** || ** Pixel Resolution* ** || ** Print Size @ 300ppi ** || ** Print size @ 200ppi ** || ** Print size @ 150ppi ** ||
 * 3 || 2048 x 1536 || 6.82" x 5.12" || 10.24" x 7.68" || 13.65" x 10.24" ||
 * 4 || 2464 x 1632 || 8.21" x 5.44" || 12.32" x 8.16" || 16.42" x 10.88" ||
 * 6 || 3008 x 2000 || 10.02" x 6.67" || 15.04" x 10.00" || 20.05" x 13.34" ||
 * 8 || 3264 x 2448 || 10.88" x 8.16" || 16.32" x 12.24" || 21.76" x 16.32" ||
 * 10 || 3872 x 2592 || 12.91" x 8.64" || 19.36" x 12.96" || 25.81" x 17.28" ||
 * 12 || 4290 x 2800 || 14.30" x 9.34" || 21.45" x 14.00" || 28.60" x 18.67" ||
 * 16 || 4920 x 3264 || 16.40" x 10.88" || 24.60" x 16.32" || 32.80" x 21.76" ||
 * 35mm film, scanned || 5380 x 3620 || 17.93" x 12.06" || 26.90" x 18.10" || 35.87" x 24.13" ||
 * Typical Resolution. Actual pixel dimensions vary from camera to camera.