Comparison of the original image with the lossy jpg version of the same photo-Courtesy of Rick Miller/Wake Forest University
Before we being, I apologize for my absence. I’ve switched jobs, switched lives basically and am just now getting settled into some kind of routine. Thanks for sticking with me during the past month of silence.
Okay…so if you’re like me you shoot in raw or maybe jpg and then rush over to your PC to download your shots and view them in some tool like Lightroom, Picasa, Microsoft Paint, whatever…
There is a reason why you should not save those precious images in a .jpg format for long term.
Everytime you open a .jpg type image you decompress the image and when you close it, you recompress it. It’s in this recompression that you wind up losing data. To understand why this happens you have to understand how compression works.
Compression works by using an algorithm to compute where changes in your file can be safely made to substitute one character for several. Now for you techies…this is a major simplification of the process. There is actually a lot that happens but suffice it to say that the original file that you started out with is stored in a compressed format. JPG uses this to reduce the size of the file and there are two formats…lossless and lossy.
If you are using lossy, you are also using a format that loses data. So everytime you open a file in Picasa, Photoshop, John’s photo viewer, etc…you are losing data. So over time, that image of your loved one, pet, flower, or something else over time, and multiple openings and closings, will start showing noticeable signs of deterioration in the digital version.
So what’s the solution? Save images in a lossless .jpg format or save them in an entirely different format like tiff, or maybe even .bmp (yes…a bitmap). Another option is to save original in their raw format that your camera shots them in, and use a lossless .jjpg for sharing and use a tiff/bmp on those images that you want to save for a very long time.
If your images are already in a lossy .jpg format. save them in a different format like tiff now. If you are just now importing images from your camera in a nice raw file mode, leave them in that mode and work with/use .jpg copies for short periods of time. Of course you can always make digital copies of your jpgs and share them.