Digital photos are built of many pixels. Each pixel has a unique value which represents its color. When you are looking at a digital photo your eyes and brain merge these pixels into one continuous digital photo. Each pixel has a color value that is one out of a finite number of possible colors this number is known as color depth.
Each pixel has a color value that is one out of a palette of unique colors. The number of such unique potential colors is known as color depth. Color depth is also known as bit depth or bits per pixel since a certain number of bits are used to represent a color and there is a direct correlation between the number of such bits and the number of possible unique colors. For example if a pixel color is represented by one bit - one bit per pixel or a bit depth of 1 - the pixel can have only two unique values or two unique colors usually these colors will be black or white.
Color depth is important in two domains: the graphical input or source and the output device on which this source is displayed. Each digital photo source or other graphics sources are displayed on output devices such as computer screens and printed paper. Each source has a color depth. For example a digital photo can have a color depth of 16 bits. The source color depth depends on how it was created for example the color depth of the camera sensor used to shoot a digital photo. This color depth is independent of the output device used to display the digital photo. Each output device has a maximum color depth that it supports and can also be set to lower color depth (usually to save resources such as memory). If an output device has a higher color depth than the source the output device will not be fully utilized. If an output device has a lower color depth than the source the output device will display a lower quality version of the source.
Many times you will hear color depth expressed as a number of bits (bit depth or bits per pixel). Here is a table of common bits per pixel values and the number of colors they represent:
1 bit: only two colors are supported. Usually these are black and white but it can be any pair of colors. It is used for black and white sources and in rare cases of black and white screens.
2 bits: 4 colors are supported. Hardly used.
4 bits: 16 colors are supported. Hardly used.
8 bits: 256 colors are supported. Used for graphics and simple icons. Digital photos displayed using 256 colors are of poor quality.
12 bits: 4096 colors are supported. It is hardly used with computer screen but sometimes this color depth is used by mobile devices such as PDAs and phones. The reason is that 12 bits color depth is the limit for high quality digital photos display. Less than 12 bits screens distort the digital photo colors too much. The lower the color depth the less memory and resources are needed and such devices are resources limited.
16 bits: 65536 colors are supported. Provides high quality digital color photos display. This color depth is used by many computer screens and portable devices. 16 bits color depth is sufficient to display digital photo colors that are very close to real life.
24 bits: 16777216 (approximately 16 million) colors are supported. This is also known as "true color". The reason for that nick name is that 24 bits color depth is considered more than the number of unique colors our eyes and brain can see. So using 24 bits color depth provides the ability to display digital photos in true real life colors.
32 bits: in contrast to what some people believe 32 bits color depth does not support 4294967296 (approximately 4 billion) colors. In fact 32 bits color depth supports 16777216 colors which is the same number as 24 bits color depth. The reason for 32 bit color depth existence is mainly for speed performance optimization. Since most computers use buses in multiplications of 32 bits they are more efficient using 32 bits chunks of data. 24 bits out of the 32 are used to describe the pixel color. The extra 8 bits are either left blank or are used for some other purpose such as indicating transparency or some other effect.
Related Articles
Digital Photo Pixel Color Formats Rgb Cmyk and Hsv
By: Chris Marshall | 03/10/2006 | Digital Photography
Digital photos are built of pixels. When you look at a digital photo on a computer screen or on a printed version of the photo you are really looking at millions of pixels each with a unique color and intensity. When put together all these pixels form the photo that you see. There are a few formats used to represent a pixel color - here are the common ones.
Getting More Battery Time From your Digital Camera Battery
By: Chris Marshall | 10/10/2006 | Digital Photography
Like other portable consumer electronic devices digital cameras use batteries as their power source. All batteries have one major drawback: they only last for a limited time. In this article we will explain what camera features consume the most energy and how you can squeeze more life time out of your digital camera battery.
The Biggest Power Consumers in Digital Cameras
By: Chris Marshall | 16/10/2006 | Digital Photography
Like other portable electronic devices digital cameras rely on batteries to power up their electronics and mechanical elements. Although battery technologies have improved a lot in the last few years they are still very limited in their energy capacity.
5 Quick And Easy Tips To Sell Digital Photos Online For Maximum Profit
By: Douglas Titchmarsh | 01/02/2007 | Internet
Selling digital photos (stock photos) can be a great way to make an additional income, and is as easy as listing your available digital photos on a stock agency's website. It needn't take too much of your time, and could make some money from some pictures you may have thought...
Carry Your Photos With You
By: Adam White | 18/03/2007 | Computers
Every year the Apple iPod gets better. Every year they come up with new and great features that people will love and become dependent upon. First, it was just great to be able to carry your favorite music with you everywhere you went. You could even set...
Brand New Digital Photo Software Guide
By: myphoto | 28/03/2007 | Software
A new digital photo software site MyPhotosoft.com provides exclusive series of full-length comparison reviews on digital photo software programs and plug-ins. Registered members have access to interactive features...
How to Get the Perfect Composition in your Digital Photography
By: Amy Renfrey | 15/05/2007 | Art
In digital photography you’ll find that the 3 main components that make up the success of your images hinge on each other. What I mean by this is that 1. Light 2. Technical knowledge 3. Composition all depend on each other closely to make up a beautiful digital photograph.
It sounds easy doesn’t it? Well it is when you have practiced. But when you are starting out learning how to get better shots with more depth and clarity you can start focusing on the technical but.....
Shutter Speed Basics
By: Amy Renfrey | 15/05/2007 | Art
I’m sure you know that one of the most important key elements to getting beautifully clear and artistic photos is firstly knowing and having a sense of the artistic. This is a very important aspect you need in order to refine your digital photography. The secret really is, combining your natural artistic flare with some precise technical knowledge…explained in layman’s terms.
Got a Question? Ask.
Ask the community a question about this article:
Frequently Asked Questions
I read somewhere that you can have yourself 'put ...
By: BEN | 27-05-2008
I read somewhere that you can have yourself 'put into' another photograph...I am no computer whiz & so would not want to do this myself; how would I go about finding someone who could do this for me at a reasonable price? I want to have myself inserted into a photo with a celebrity.....any ideas??? thanks!!
Who is the photographer that made "Lunchtime a top ...
By: anamana | 23-07-2007
Who is the photographer that made "Lunchtime a top a skyscraper"?
Hi my friend! Everything ok? I've a day off. My ...
By: Marije Zuurbier | 23-07-2007
Hi my friend! Everything ok? I've a day off. My parents are on a holidays with my youngest brother and the other one is here. I've to take care of him ;). Question. You made a nice photo of the toilets in El Retiro right? Can you send it me?
Is it possible to download Adobe Photo Shop ...
By: narankamal | 23-02-2007
Is it possible to download Adobe Photo Shop Starter Edition 3.0 in normal form instead of Zip? After downloading the file and running the set up from the zip file, the software does not work on application and hangs. Why?
Q&A Powered by:
More from Chris Marshall
Building A Home Cinema System
By: Chris Marshall | 16/05/2008 | Art and Entertainment
When planning and buying your cinema home room it is always a good idea to browse the Internet fully and consider what options will be best for you and what will be best equipment for situation depending on many things such as budget and the space you have.
Selling Online Advice And Tips
By: Chris Marshall | 16/05/2008 | ECommerce
When you are looking into selling your items on auction websites such as ebay there are plenty of things to consider that can help the transaction go as smoothly as possible.
Fat Loss Advice - Diet Exercise Fat Loss Weight
By: Chris Marshall | 13/05/2008 | Weight Loss
People searching for fat loss advice are often people who want information about the best ways to lose weight and what will be most effective for them personally.
Market Competition Perfect and Monopolistic Competition
By: Chris Marshall | 07/05/2008 | Sales
The business community continually changes and ownership of businesses change hands as smaller entities are swallowed up by bigger corporations. We hear about it all the time in the news, but yet very few people can name a example of monopolistic competition, or realise what the definition monopolistic competition is.
Geothermal Energy Facts: Geothermal Energy Pros and Cons
By: Chris Marshall | 27/04/2008 | Environment
There is much talk about climate change, and the search for viable renewable energy sources. Everyone knows about the likes of solar, wind and wave power. But fewer have heard of geothermal, or know how does geothermal energy work.
Why Grand Theft Auto 4 Is The Biggest Video Game Of 2008
By: Chris Marshall | 26/04/2008 | Computer Games
Grand Theft Auto 4 is set to be released next week and game analysts are suggesting that it is not only the biggest release of the year but also the game that could really push on the sales of the next generation consoles.
Global Warming - Does Global Warming Lead To A High Death Rate
By: Chris Marshall | 26/04/2008 | Environment
Global warming can affect everything and it could eventually affect the death rate of our population if things do continue to get worse over the next few years.
Rockstar Reveals Details About About GTA4 New Online Modes
By: Chris Marshall | 24/04/2008 | Computer Games
Rockstar have revealed some brand new details about some of the different online modes in the next version of Grand Theft Auto.
Hobbies 
