DPI has NOTHING to do with your digital image quality. Dots Per Inch (DPI) is a measurement only relevant to printing. Many software programs use DPI to set image quality and this leads to confusion. The more relevant factor in digital image quality is Pixel Dimension. Focusing on this value instead will allow you to accurately establish the quality of your digital images for use in ProShow. Leave DPI to the print world.
Can you tell the difference between the two images below?
There are four main factors that determine the image quality:
- The quality of the recording device (camera’s optics and sensor, etc)
- The size (pixel dimension) of the digital image
- The digital format it is stored in (lossless vs. lossy compression)
- The technical proficiency and the ‘eye’ of the photographer
There are other factors that come into play in regards to the quality of your digital images, but the points we touched on above determine the overall quality of your images.
The size of a digital photo is measured in pixels (the smallest color component in a photo). The two photos above have the same pixel dimension, 300 pixels in width and 225 pixels in height. Even though their DPI has been set to radically different values, the digital images are identical in quality (the pixel density doesn’t change).
Lets take a look at what happens when we print these images…
As you can see in the illustration above the images are dramatically different from one another when printed to an 8.5″ x 11″ sheet of paper. However, the pixel dimension is unchanged. This is why the image looks extremely different when printed. The purpose of this illustration is to show you the purpose of DPI and how it is completely irrelevant when working with images in the digital form.
So what resolution do we recommend you use in ProShow?
We recommend that you use in ProShow the highest resolution images you have available. The higher the pixel density the better and only the resolution of your image determines its pixel density, not DPI.
If you must re-size your images for a show we suggest that you at least match them to the resolution of the device that you will be displaying the show on. For example, if you plan on displaying your show through a projector and the projector has a native output resolution of 1024×768 then your images, and any video output, should be at that resolution. Larger images will also work but you don’t want to use anything smaller. Doing so could introduce unnecessary upscaling and result in quality loss.