What is “DPI” and “PPI” are they the same or different?

This can all be very confusing, but if you don’t have a basic understanding, you might actually be very disappointed with your work when you go to print.

Following is short “tutorial” that had been posted on the Digital Scrapbook Place website.  I can’t credit the author because none is listed.  I hope you find it helpful.

Tutorial: DPI- PPI – what does it all mean???

You often hear people talking about how important DPI is in scrapbooking – You hear people saying – oooooooh thats got to be 200 DPI or its no good – – What ARE they talking about?

Actually they are talking about PPI – the correct terminology for the type of graphics we are using on screen is Pixels Per Inch . DPI or dots per inch refer to the printing or scanning process only and not to the process of element creation at all.

Pixels per inch is exactly what the term sounds like – the number of pixels an image contains per inch.

Each image is made up of tiny rectangles – known as a pixel- – the density of those pixels per inch is known as the PPI.

Here at DSP we create our Elements to be printed at 200PPI therefore a 12 inch by 12 inch background will be 2400 pixels across 2400 pixels down.

If we were to tell the printer to print this image at 8 inches by 8 inches – the pixels would be shrunk and each inch would now contain 300 pixels ( so you could say the image is now 300 ppi.)

If we were to tell the printer to print the image at 2 feet by 2 feet – the pixels would be enlarged – and each inch would now contain only 150 pixels.

BUT the original image is still 2400 pixels by 2400 pixels. – you see it doesn’t matter what the PPI says – – the image itself still has the same number of pixels.

The quality issues arise when you take an image and stretch those pixels out too far – so that you can see each pixel rather than them blending together.

Each image editor is different – Often they will open an image and the information will say that the image is a certain number of pixels and the resolution is 72 ppi

this may be the default setting that this image editor opens all image at. Other image editors open images at the resolution that the image was created .

It really doesnt matter – it is the number of pixels contained in the image that is important –


Here is an example

below in figure one is an element – it is 300 pixels by 300 pixels and my image editor says it is 200 dpi – it says that it is 1.5 inches by 1.5 inches.

fig 1

 

In figure 2,  I have placed my element on a new canvas for my scrapbook page which I have made 12 inches square at 200ppi

fig 2

 

Figure 3 shows another element – it is also 300 pixels by 300 pixels but the image editor shows it to be 72ppi

fig 3

 

Note also that it says the image is 4.167 inches

Now I will place this same image on my canvas

fig 4

 

Notice that both images are identical -!!!!

It is really the number of pixels contained in an image that is the important factor .

 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Digital Graphics Artist Designing for My Memories

%d bloggers like this: