Digital Photography 101
Chapter 1: Introduction to Film and Digital Cameras
1.5: Resolution
Resolution is something we are bombarded with in the digital world.
It has created a whole new realm of confusion in what is required
to make a good print to a specific size and in what file format.
I hope to make it a little clearer for you.
Resolution is the number of pixels in an image. The more pixels,
the higher the resolution. The higher the resolution, the bigger
the picture. (A pixel is a coloured square dot.)
I have inserted a table to help demonstrate what we mean by resolution.
This table is fifty pixels wide and twenty pixels high. Each square
is a pixel. The resolution of this table is 1000 pixels because
50 x 20 = 1000.
Your consumer branded digital SLR camera may be 6 million pixels
or 3000 x 2000 pixels. That's a lot of tiny squares.
We hear a lot about DPI. DPI is Dots per Square Inch and is a standard
of measurement for the resolution of images. The higher the DPI,
the higher the resolution.
The relationship between DPI and resolution can often cause confusion,
but remember the lower the DPI the less pixels we need to fill a
square inch.
If we take our six million-pixel image and print it at 200 dots
per square inch it stands to reason it will end up being a lot larger
then if we printed it at 300 DPI.
So what is the standard and how so? RGB (RED, GREEN, BLUE) Printing
systems such as laser printers are getting better and able to use
lower DPI to make larger prints from smaller resolutions. If we
are selling a photo to a publishing company for use in a calendar
then they will probably want to print it on an OFFSET printing method
and will require the image to be at least 300 DPI. Offset printing
is a method, which uses four coloured plates or CMYK. Cyan, Magenta,
Yellow and Key (black). The paper or media is passed over each plant
to introduce each colour with the blending happening on the paper.
A six million-pixel file will print to about eleven inches on
its longest side at 300 DPI. We can use Photoshop to increase the
resolution to accommodate larger prints, which we will discuss later.
We will also go over printing methods, file types and colour space
when we look at Photoshop.
To better understand DPI let's look at how the human eye sees
pixels. We do not want the viewers to see each pixel, as we want
them to see a blend of dots creating a seamless image. When viewed
close up the tiny dots in a good quality print will become blended
to the eye at 300 DPI and over.
Our computer screens are different. We are seeing a light source
coming direct into our eyes from our screens so the DPI can be a
lot lower to create the same seamless blending of colour. This is
called additive colour mixing. On our screens this can be 72 DPI
and over, which is why our screens are about 1200 pixels wide and
800 pixels high. That's only 960,000 pixels.
It stands to reason the higher the resolution the bigger the print
at the same DPI. I will try and give you a better understanding
of resolutions when we cover Photoshop later.
Wedding Photography Tutorial ebook
BUY
NOW
|
|
|
|
|
|
|
