Digital image quality

When we talk about the quality of a digital image we usually are thinking of two things:
• the total number of pixels that compose the image
• the number and accuracy of the colors in the image

The number of pixels is expressed in two ways:
• the dimensions. For example, an image might be said to be 1024 x 768 pixels
• the total number pixels in the image. For example, an image might be said to be a 1.5 megapixel image.

An image file with more pixels will produce a higher quality image and will make larger prints better than an image with fewer pixels.

The second quality measure is the total number of colors recorded in the image file. We call this the bit depth of the image. It's the number of colors possible in a digital file.

Sometimes the number of colors is referred to as bits per color channel. Most image files have three channels - red, green and blue. This results in three times the bits per channel.

• 8 bits per color channel or 24-bit total color = 16.7 million colors
• 8-bit color = 256 colors
• 4-bit color = 16 colors
• 1-bit color = 2 colors

Digital cameras

Our digital cameras allow us to concentrate on the content of the photo while the camera does most of the technical work. We can see and edit our photos instantly.

Once there was only print media and then, not long ago, we could display our digital photos on traditional websites. Today we add to that 21st century media technologies such as blogs, wikis, Twitter streams, Flickr images, podcasts, YouTube videos, social networks, virtual worlds and machinima.

Here's a web page where you can learn more about New Media technologies:
http://www.uncp.edu/home/acurtis/NewMedia/NewMediaCommunicationTechnologies.html

And a collection of New Media buzzwords in a glossary:
http://www.uncp.edu/home/acurtis/NewMedia/NewMediaBuzzwords.html

Flickr is all about digital still photography. Here's the Flickr photostream for the Photojournalism & Photojournalists group, which has thousands of members:
http://www.flickr.com/groups/p-p/

The Flickr blog:
http://blog.flickr.net/en

Photobucket is another image-sharing website:
http://photobucket.com/

Photobucket's photojournalism collection:
http://photobucket.com/images/photojournalism/

An example of a photography blog known as The Digital Journalist:
http://www.digitaljournalist.org/

And an example of a wiki. This one is called Photography Wiki:
http://photography.wikia.com/wiki/Main_Page

Here's a list of Twitter photographers:
http://wefollow.com/twitter/photography

And a directory of photography news on Twitter:
http://twitter.com/photographynews

The official Facebook page of photojournalism:
http://www.facebook.com/pages/PhotoJournalism/31072184215

The New York Times "Lens Blog" is a photo viewer of images, which some might say represent the best photojournalism in the world. It's a visual journalism archive:
http://lens.blogs.nytimes.com/

A collection of digital still portrait photography and photojournalism on YouTube:
http://www.youtube.com/watch?v=V9HQygVbfGM

See also the Photography, Photojournalism, Video and Machinima headings on my Resources for Courses page:
http://www.uncp.edu/home/acurtis/Courses/ResourcesForCourses/ResourcesForCourses.html