Image resolution describes the amount of detail an image holds. The greater the resolution the greater the detail. The resolution of an image is directly dependant on the dimensions, as we increase the size of the image the resolution decreases and vice versa.
A common misunderstanding is that image resolution is measured in 'Dots Per Inch' (DPI), this term actually applies to the resolution of the print itself, where tiny dots of different colours make up the printed image. The correct term for image resolution is 'Pixels Per Inch' (PPI), which measures the number of single colour squares (pixels) there are per inch at a specified dimension.
Although an image may appear okay on your computer screen this is not a good guide as to how it will print. To reproduce the image in print, much higher resolution is required. Image resolution on web pages is typically 72ppi and when printed will appear quite pixelated. The same will occur if you make your images larger than they can be printed at an acceptable resolution. Our software will display warning messages when the image resolution is not best quality.
The lower the resolution, the lower the quality of the print. The required resolution for optimum quality photographic print is 250ppi to 300ppi. Image resolution lower than this will reduce the quality of the print. Resolution between 150ppi and 250ppi is acceptable however some loss of image sharpness and small pixelation may occur. Where the resolution is lower than 150ppi images will print blurred and pixelated and are not recommended to be used.
The number of megapixels of your camera is independent to the image resolution, however the more megapixels allows you to print your image at a larger size with good resolution.
Please note that resolution isn't the only factor in photo quality and print quality. Other factors also play a significant role in determining how your digital photos will look when printed:
- Correctly exposed photo and lighting conditions
- Lens quality (sharpness of image)
- Steadiness of camera
- Focus on the subject
- Proper shutter speed for moving or stationary subject
- Clean equipment
What size can I print my photo?