By David Peters

Digital photos can be viewed in many different ways, but more than likely you will be viewing them on computer screens or on printed paper. Most prints will be on standard paper sizes such as 4X6 or 5X7. But every now and again, you may have that special photo that you want to make an enlargement of. The quality of print enlargements depends on you digital camera mega pixels figure.

There is a certain resolution referred to as number of pixels in each digital photo that you take. Pixels can be represented by one number or sometimes as two numbers depicting the number of pixels over the X axis and the number of the Y axis (multiply these two numbers together to determine the total number of pixels in the digital photo).

You are actually printing these digital pixels on paper when you print your digital photos. If the paper size is big and the resolution is large, the digital print quality will be poor. The end result can be the ability to actually see the individual pixels on the print. This is known as pixelization.

So how can you establish what is the maximum print enlargement potential of a particular photo? The answer depends on many factors. Not only are the actual number of pixels in the photo a factor, other things can influence the answer such as the number of details in the photo and what the lighting conditions were to name a few. Plus as different people have different levels of what is acceptable in regards to quality, even the number of pixels can vary dependant on the individual.

A rough assessment of what comprises a good print quality is based on the pixels density or in other words the number of pixels per inch on the printed photo. This is also known as PPI (pixels per inch) and it represents the number of pixels over an axis line.

Experiments show that the following qualities are usually associated with a specific PPI number:

PPI 100 - fair to bad

PPI 200 - good

PPI 300 and up - very good

The next reasonable step would be to determine how many mega pixels are needed for good quality printing on a specific paper size. Calculating this number is very easy. All you need to do is to simply multiply the page length by its width in inches, resulting in the number of square inches on the page. Now multiply this number by the square of the PPI number and the result is the number of pixels on the page which is the number of pixels we want our source photo to have. Here are the numbers calculated for some common sizes (for 100,200 and 300 PPI respectively):

page 4X6 0.24MP 1MP 2MP

5X7 0.35MP 1.5MP 3MP

8X10 0.8MP 3MP 7MP

11X14 1.5MP 6MP 14MP

page 16X20 3MP 12MP 28MP

page 20X30 6MP 24MP 54MP

This is just a representation of what is considered an appropriate number of mega pixels for various paper sizes. Consider all of the factors when making enlargements. Although it can be expensive, experimenting with different paper sizes is best. Sometimes what is normally poor quality pixelization can actually create a creative artistic effect in a photo. This means that in addition to the above calculations, common sense and experience are also needed to determine the best photo enlargement size for a specific digital photo.

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