|Bevolee. CD Disc with Colours. 2005-Jan-01. 2012-Aug-07. http://flic.kr/p/5V1VWJ|
Whether they've been transformed from paper prints into digital images using a photo scanner, or were born that way with a digital camera / smartphone, you now want to archive them. To make sure they are safe, many will choose to use optical storage such as a CD, DVD, or BluRay disc.
How Many Pictures Can My Disc Hold?
While this is a great question, the answer is not an exact one for a number of reasons. For instance, a regular CD-R (burn once CD) holds about 700MB of data. However, some can hold as much as 800MB or 900MB affecting the number pictures a disc can hold. Also, higher quality resolution of a photographic image results in the need for more space to store the associated data. On ArchiveMyPhotos.com, the website’s authors offer this; “How many photos will a CD hold? The short answer is a lot. The long answer is it depends on your camera, the image size and the quality of your jpeg.” They then go on to provide a chart to help offer an estimated number of photos you can expect a CD to hold.
The Math! Understanding the fundamentals in determining digital image size can go a long way in helping you plan ahead for your media, archival discs, RAM and other digital storage memory needs. When working with digital images it is possible to get a bit closer than answers like “a lot” or “it depends”. But, to do so will requires some good old fashioned mathematics.
The formula is: [(Height in pixels) x (length in pixels) x (bit depth)] / 8 / 1024 = image size in kilobytes (KB)
According to ehow.com; “Images are frequently measured in inches with an associated DPI (dots per inch) resolution. To obtain the height or length of an image in pixels, the height (or length) need only be multiplied by the DPI. For example, a 6-inch x 8-inch photo with 300 DPI is calculated by multiplying 6 X 300 and 8 x 300, which equals 1800 x 2400 pixels.”
Bit depth is directly associated to the number of bits used to store the value of the color in your photos, thus having an impact upon storage requirements as the formula states. You also will want to take into consideration your images are using any type of compression algorithm given its use actually makes the image file size smaller.
Having fun yet? Well, after reading through all the above you might just want to download this Memory Storage Calculation ‘cheatsheet created by Professor Jonathan Eckstein from Rutgers Univeristy. It is a handout presenting the basic concepts and calculations pertaining to the most common data types, including digital picture images.
If you are still struggling with the math, you can check out the answer to How Many Will Fit? on DigMyPics.com where they have done the calculations for 3x5, 4x6, & 5x7 photographs to come up with some pretty fair estimates.
A Global Authority & Information Repository on Optical Data
Still looking for more information about optical data? Then, the Optical Storage Technology Association (OSTA) is a great place to turn next.
OSTA is an international trade association focused upon promoting the use of recordable optical technologies and products. Its membership includes optical product manufacturers and resellers from three continents, representing more than 85 percent of worldwide writable optical product shipments.
The OSTA works to shape the future of the industry through regular meetings of Commercial Optical Storage Applications (COSA), DVD Compatibility, Marketing, MPV (MusicPhotoVideo), UDF committees, and a new adhoc Blue Laser committee. Interested companies worldwide are invited to join the organization and participate in its committees and programs.
To help the public, the OSTA has made available a couple of PDF resources to help better understand optical storage and its benefits. Both are free and offer an informative insight in helping us better answer...Just how many pictures can I save on this disc?