lburriss

This is a spin-off from an earlier topic about which format to use to save files.

I understand that every time I edit a JPEG I lose a bit of data. But let's say I have a file, JPEG-1. I open it, save it as JPEG-2, and edit JPEG-2. JPEG-1 is still in its original location, unedited. Later I open JPEG-1, save it as JPEG-3, and edit JPEG-3. See what's happening: I'm making a copy and editing the copy, not the original JPEG-1.

So, am I losing data every time I open and close JPEG-1, or only if I edit JPEG-1 and then resave it as JPEG-1?

Papa Joe Loc: Midwest U.S.

No. As long as you're not changing the original in any way, opening and closing it does not degrade the image.

GoofyNewfie Loc: Kansas City

If you save your edits as another name, you lose nothing from your original "jpeg-1".
One thing some don't know about: you can do a lot of editing to a jpeg using Adobe Camera Raw.

Morning Star Loc: West coast, North of the 49th N.

Just opening and closing a .jpg file does not cause it to lose information. It is saving the file that does that. So as long as you remember to Save As and rename, your original will remain the same.

amehta Loc: Boston

No, you do not lose any data every time you open and close JPEG-1. But instead of "open and save-as", you could "copy". That way the only file you open is the copy, and there is no risk of saving to the original.

jimq Loc: Cape Cod, MA

If you don't re-save it and you will always have the original. You can look at it as many times as you want without losing anything.

GoofyNewfie Loc: Kansas City

An ounce of prevention! Good tip.

camerapapi Loc: Miami, Fl.

Another easy solution, save the original JPEG as a Tiff.
Now open it, save it, work on it or do what you want with it, it is a lossless file.
In spite of all this I still prefer to save the original as a Tiff and work with a copy.

Mormorazzi Loc: Temple, Texas

Just tagging in. I'd like to know the answer to this one, too.

Wahawk Loc: NE IA

Set your software to SAVE or SAVE AS for JPG files with MINIMUM compression/best quality and you will lose very little from the original.

However, it is still ALWAYS best to work on a COPY of the original.

Wahawk Loc: NE IA

:thumbup: :thumbup: EXACTLY :thumbup: :thumbup:

DaveMM Loc: Port Elizabeth, South Africa

If you expect to go back to editing an image, then save the intermediate copy as a native editor file, i.e. as a Photoshop file in PS or PSE. Then you can do more editing without having to redo the earlier work.

Even better, learn to use layers in the editor and you can undo part of the edit without any loss of original quality.

Best, if your camera will save in RAW, use RAW.

RichieC Loc: Adirondacks

DaveMM has your answer.

Perhaps it might help if you understand what JPEG is and a bit of how it works so you can decide what is best for you.

JPEG is an acronym that stands for "Joint Photographic Expert Group" ( TIFF stands for Tagged Image File Format)

All JPEG is, is a compression algorithm. When you capture a photo, every pixel is assigned a number that is really a recipe of RGB colors that your computer follows to turn into a graphic image as it apperas on your screen or that you send to a printer. The image itself is digital..a large pile of numbers.

An image can have a lot of numbers. So JPEG looks at all numbers that are very similar and makes them the same number, then rounds it down to an 8bit number from the 12 or 14bit original RAW capture. Then it writes a bit of code to keep track where these same pixels are located in the image, and by combining these into a group- makes the files size much smaller. The result is an acceptable trade off between accuracy, quality and file size.

If you have noticed, there are several levels of jpeg , basically the lower levels pick a wider range of similarly colored pixels to average- these can make an image "blotchy" but very small - number-wise.

Every time you save a file as a jpeg- even at its very highest setting, it runs this algorithm again and averages more pixels that it already ran in the first run- thus you loose unique colored, subtle differences between pixel colors. a field of red becomes a single carpet of the very same red.. ( this is simplified- but you get the idea) when the original may have had subtle differences of red.

A better workflow is to convert the jpeg as stated above, to a photoshop or tiff ( both "lossless" compression algorithm's themselves) and only save as jpeg to display or upload or even to print, keeping your original in a lossless format. JPEG is very widely supported, and a first generation JPEG does a very good job at displaying an image- albeit truncated forever...

RAW is what JPEG's are made from- every pixel as originally recorded in its most accurate form. All available for future processing. But you have a large file to deal with.

Claree Loc: Near Buffalo, NY

Thanks, Richie C for the wonderful explanation of JPEG, TIFF and Raw. I've been reading forum topics for a few months now, and was inspired to actually participate after reading your response. UHH has so much to offer, especially for hobbyests like myself, trying to break into manual mode. I appreciate the kind and generous spirit of many like yourself on this site.

BobbyT Loc: Southern California

JT's images are excellent. I love the effective images , but that raises a question that I've had for some time, namely:
In this modern age of special effects and software post process editing, how do we classify a "great photo or a great photographer"? Are these terms extinct? Do we need new terms to describe how images are presented?
Maybe we should classify "great photographers" as those who produce great unedited images with "minimal editing", and those as great artists who produce great "collages images" with photos and much post processing.
There are probably many other options and terms but I hope you guys get the point.
I thought that maybe this might be a good topic for discussion.