How many pixels per inch are necessary, to make a good-looking print?
The ‘key word’ PRINT, as in on paper or material, or other tangible medium. Ultimately, and generally, the more pixels per inch (ppi) the finer the detail in the print will be, and the sharper it will look because there is ‘more’ information, contrast, and ‘edge details’ captured within the image. This is important… but also depends on HOW the image is being printed.
The minimum number for reasonable print quality is 120ppi (usually like old school news paper print). For most modern day, practical purposes (and printing color images), 180ppi is the generally accepted ‘minimum’ for prints. Understand, 300ppi is recommended and usually ‘industry standard’ for the best print quality on most printers, and output devices. The more ppi (pixels per inch), the finer the detail the printed image will be… and the sharper it will ultimately look. Remember, the average LCD/LED computer screen is only capable of 96ppi max (72 dpi= dots per inch, if an old square CRT type), so just because it ‘looks’ good on a screen, doesn’t mean it will look as good IN PRINT.
The table below shows the minimum file size you need to make the most common sized prints. For example if you want the highest quality 8×10 print you’d need 2400×3000 pixels which you could get from an 8MP camera image (uncropped). However, if you didn’t need the highest quality, you could usually still have a ‘nice looking’ 8×10 print with 1440×1800 pixels; which is possible from most any modern camera (including phones), with just a 3MP sensor size.
|File size required for Print|
|180ppi (good)||300ppi (best)|
|4×6||720×1080 – 0.77MP||1200×1800 – 2.16MP|
|5×7||900×1260 – 1.1MP||1500×2100 – 3.15MP|
|8×10||1440×1800 – 2.59MP||2400×3000 – 7.2MP|
|11×14||1980×2520 – 5MP||3300×4200 – 13.9MP|
The better the image quality, to start with, the better the final print quality. Remember, GIGO (Garbage In, Garbage Out). In general, you’ll get superior results from a dSLR (digital Single Lens Reflex… aka Professional style camera) than you will get under the same circumstances from a super small sensor, such as what most camera phones use (regardless of claimed ‘megapixels’). This is because the dSLR has a larger sensor, larger pixels, captures more data, has less ‘pre-processing’ (compression) in device, and captures more contrast, and ultimately an opportunity for greater image quality.
This is even more amplified when the images are captured in ‘RAW’ format, vs the compressed JPG format.