banner.gif (3613 Byte)

Corner.gif 1x1.gif Corner.gif
1x1.gif You are at: Home - Discussion Forum 1x1.gif
Corner.gif 1x1.gif Corner.gif
round_corner_upleft.gif (837 Byte) 1x1.gif (807 Byte) round_corner_upright.gif (837 Byte)
Old 01-26-2006, 02:40 PM   #1
Senior Member
Join Date: Jun 2003
Location: New Jersey U.S.A. ex UK and Canada
Posts: 4,860
Send a message via AIM to johnfowles

Further to my display of picture of Gord on the general forum at:-
Here are more things to ponder aboot digital picture file sizes
I was describing a large sample raw (bitmap) file of 3601 KB (actually 3,686,455 bytes)
It was a picture whose dimensions in pixels was only 1280 by 960=122800 pixels
Note that this is obviously from a camera taking pictures of a bit more than 1.2 megapixels considering that the price of digital cameras has fallen so much you can see how gigantic files from say an 8 megapixel camera will be in their raw uncompresed state
I converted the bmp to the jpg compressed "lossy" format using MGI Photosuite which also told me that it was only 1280 by 960 pixels.The bmp filesize can be calculated simply by multiplying the pixel dimensions and then multiply the resulting mumber which is the total number of pixels by three (since each pixel's colo(u)r has to be individually defined by one "byte" for each of the three colors magenta cyan and blue that combine to produce the RGB
"red", "green" and "blue") color code. in this case 1280x960x3=3,686,400 the actual file is a bit larger as it also has a file detail header).

Fair enough but why "cyan" and "magenta" instead of "red" and "blue"?I never knew but a google revealed
"Cyan and magenta are actually old printing terms for blue and red"
and are used for reasons fully discussed at:-
see also:-
where you can read:-
"The amount of memory, in bytes, that a 24-bit image occupies in its raw state, can be found by multiplying the number of pixels in the image by 3. A 640 480 24-bit RGB color image will have 640 480 = 307,200 pixels. Thus, the memory space required is 307,200 3 = 921,600 bytes = 900 kilobytes"
These "wiki" pages are something else!!
John Fowles

[ January 26, 2006, 14:48: Message edited by: johnfowles ]
johnfowles is offline   Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
A Brush with the Famous continued johnfowles Small Talk 1 08-20-2009 01:10 PM
British Comedy/Humo(u)r continued johnfowles Small Talk 3 02-22-2007 01:14 PM
Gordon's Christmas Box Set... continued johnfowles General Discussion 18 12-20-2006 08:52 PM
Piracy-continued johnfowles Small Talk 1 05-16-2006 06:49 PM
Query re digital pictures Auburn Annie Small Talk 5 12-30-2004 01:06 PM

All times are GMT -4. The time now is 03:36 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
downleft 1x1.gif (807 Byte) downright