JPEG Generation Loss/ JPEG Artifact: This is a quote from a Nikon D3300 Field Guide by Dennis Thomas: "Every time you open, alter, save a JPEG, it loses a small amount of detail. After...

bobishkan Loc: Fort Myers Sunny Florida

This is a quote from a Nikon D3300 Field Guide by Dennis Thomas: "Every time you open, alter, save a JPEG, it loses a small amount of detail. After doing this multiple times, the image starts to deteriorate. Eventually the image will look pixelated." My question is how many times can I open a picture on my computer before I start to loose some quality? Is this a problem in the real world? Thanks Bob

bobishkan Loc: Fort Myers Sunny Florida

maybe

sandiegosteve Loc: San Diego, CA

Loss only happens when you save changes. It is the saving process that causes the loss.

Longshadow Loc: Audubon, PA, United States

sandiegosteve wrote:

Loss only happens when you save changes. It is the saving process that causes the loss.

Correct!
You can view it a bazillion times without any degradation of image quality.

CHG_CANON Loc: the Windy City

bobishkan wrote:

This is a quote from a Nikon D3300 Field Guide by Dennis Thomas: "Every time you open, alter, save a JPEG, it loses a small amount of detail. After doing this multiple times, the image starts to deteriorate. Eventually the image will look pixelated." My question is how many times can I open a picture on my computer before I start to loose some quality? Is this a problem in the real world? Thanks Bob

Others have already started to correct your understanding ... The key point is open, alter, save a JPEG. The key point is alter and save, not copy, not open. If opening a file or copying to new locations was a problem, this would be a huge real world issue rather than a minor minor issue limited to excessive re-working of copies of copies of copies of an original image.

bobishkan Loc: Fort Myers Sunny Florida

Thanks for the help. The quote in a photo book said "open" and that is what confused me. Actually in this how to book on the D3300, I found a few other mistakes that I know are wrong. Guess the author should not be writing books to teach others what he doesn't know himself. Thanks to all! Bob

CHG_CANON Loc: the Windy City

The wording should be clearer and include some clarifying examples. The issue is not open or alter or save. Rather, the three actions done together as in: open and alter and save the results.

bobishkan Loc: Fort Myers Sunny Florida

Thanks again for the info. First time I have used this site. Nice to get an answer from an obvious expert on my question. Me thinks, I'll use this site more often. Up till now I have been lurking! Bob

CHG_CANON Loc: the Windy City

Welcome aboard, Bob! Just try to avoid the war of experts on hot topics like filters, SOOC, ETTR and of course, N v C v everyone else ...

rgrenaderphoto Loc: Hollywood, CA

Really? In all my years of modifying and saving JPG files, I have never, ever seen image degradation and/or pixelation . Maybe its after a zillion saves?

joehel2 Loc: Cherry Hill, NJ

Welcome to the forum.

jerryc41 Loc: Catskill Mts of NY

bobishkan wrote:

This is a quote from a Nikon D3300 Field Guide by Dennis Thomas: "Every time you open, alter, save a JPEG, it loses a small amount of detail. After doing this multiple times, the image starts to deteriorate. Eventually the image will look pixelated." My question is how many times can I open a picture on my computer before I start to loose some quality? Is this a problem in the real world? Thanks Bob

Welcome to our forum!

Opening and saving doesn't hurt the images. It's making changes and then saving that supposedly hurts the image. I made changes to an image over 100 times, saving it after each change. There was no difference I could see between #10 and #100.

Ctrclckws

Many of the photo editing programs allow you to save the file with a varying degree of lossy compression. If you save files with higher quality settings, the degradation of the image is minimal. But if you specify lower quality, degradation of the image will be visible fairly quickly.

Test it yourself, take an image, save it as a number 2, at a lower quality setting, then open the number 2, and save it as number 3, etc.
It won't take long to see a difference

photophly Loc: Old Bridge NJ

Welcome to the Hog

CatMarley Loc: North Carolina

bobishkan wrote:

This is a quote from a Nikon D3300 Field Guide by Dennis Thomas: "Every time you open, alter, save a JPEG, it loses a small amount of detail. After doing this multiple times, the image starts to deteriorate. Eventually the image will look pixelated." My question is how many times can I open a picture on my computer before I start to loose some quality? Is this a problem in the real world? Thanks Bob

If you open it and close it without editing, it will not lose anything. Always edit a copy, never the original, then you don't lose anything from your original JPEG,