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Photography Question 
Dianne Gill
 

Layman's terms for TIFF & Jpeg


I'm writing about TIFF & JPEG format but I want it to be an easy understandable read for the average person. Any research I've done is a complicated explanation. Any ideas how to break down the long versions or where I can go to read about TIFF or JPEG in layman's terms?
Thanks for your help.


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2/21/2007 6:30:00 AM

 
doug Nelson   See scantips.com for good explanations of these. TIF is Tagged Image File Format. It contains, simply put, the most digital information with NO compression of the file. JPEG, or Joint Photographic Experts Group exists to reduce photographic images to file sizes easily handled by the web and for emailing attachments. The trick is to retain the image's color and structural integrity with as little degredation to the image as possible.

The very capture of a jpg image in my little point-and-shoot results in an immediate compression of the file. Each subsequent edit and save further compresses the file, depending on how high you set the jpg compression in your imaging program. With the high quality jpg's produced by top-line cameras, it makes litle difference. A journalist shooting high quality jpg's to submit quickly to his editor is not going to sweat the slight iamge degredation involved.

What DOES matter is tonal and color editing in fine, serious work. This is better accomplished in TIF or RAW formats, because you have more digital information to work with.


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2/21/2007 8:27:19 AM

 
Alan N. Marcus   Hi Dianne,

Did you ever count on you fingers? Most of us do. We use our digits (fingers of the hand) as helpers. Digital photography means expressing pictures using numbers. If you examine the Sunday comics with a magnifying glass, you will see that the pictures are constructed using tiny dots of ink. If we agree in advance on a code, we can send pictures from place to place electronically. Code values (numbers) that express intensity can be transmitted very fast. The tiniest dot (point) that contains intelligence as to intensity is known as a pixel. This is shorthand for picture element. When we digitize a picture we fracture the image into a myriad of pixels (tiny points) and assign each a value. Commonly this value will be between 0 (zero) and 255 (256 separate intensities). Often the pixel is than subdivided to send color information. This way we can transmit values for the three primary colors red – green – blue. This method allows transmission of color pictures. Often using only 256 discrete values can be too coarse, we can expand the number range, this allows the transmission of a greater dynamic range.

Anyway, by now you can see that transmitting a picture using numbers becomes complex and lengthy. We need to figure out a way to reduce the number of numbers we are transmitting and ultimately putting in storage. Compression comes to the rescue. Smart fellows and girls have been working on this problem for years.

JPEG is a compression process used to reduce the size of digital picture files. When used, software logic looks at picture data and casts out some of the pixel values. The finished compressed file yields a picture that is not as good as the original. The JPEG compression method tries to toss out only those pixels that are not too important. If fact, most of the time the discarded pixels are ones the human eye can’t perceive very well. Using JPEG, file size can be reduced three fold.

TIFF is a compression method that can reduce file size slightly, about 30% without degrading the image.

Newer compression processes are coming along. A new and improved JPEG is already in use.

I hope this helps,

Alan Marcus
ammarcus@earthlink.net


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2/21/2007 8:45:42 AM

 
Dianne Gill   Thank you both, your responses were helpful! I've been to scantips, it's a great site but sometimes overwheling....
Doug, great pics!


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2/22/2007 7:30:05 AM

 
Kay Beausoleil
BetterPhoto Member Since: 5/31/2004
KayBeausoleilPhotography.com
  Dianne, just a thought from my experience with our camera club: I gave a talk to a bunch new to digital. When it came to formats, basically what they wanted to know is "what should I use, and when", so I went summarily through the advantages and inconveniences of each. Then we went through the stage of "OK, so what do you use?", which I told them, repeating what I'd just said in a different way. Then I asked "would you like to know what TIFF, JPEG and RAW mean or how they work?" Answer: dead silence, followed by a question on light balance.

So my thought is: keep the technical stuff to a minimum if you're writing for an audience you already have to simplify for.


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2/22/2007 7:45:02 AM

 
Kay Beausoleil
BetterPhoto Member Since: 5/31/2004
KayBeausoleilPhotography.com
  OK, so please imagine just YOU is in bold characters -- my HTML went wrong somehow!


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2/22/2007 7:46:25 AM

 
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