Degrading photo quality?

[Jayell]

So I open my jpg in Photoshop in order to change the File Info (Edit->File Info). I make NO changes to the photo itself. Being as indecisive as I am, I end up opening, changing something in the File Info, and saving several times. Am I degrading the photo quality by the repeated saves?

[Steve Grisetti]

Yes. But only because it's a JPEG.

TIFs and PSDs use no compression. That's why their files are so large. Every pixel is saved.

JPEGs use a compression in which pixels of similar color are averaged every time you save the file. Depending on the level of compression you're using, this averaging can be mild or it can be extreme. That's why JPEGs sometimes produce "artifacts" when highly compressed or re-compressed several times.

Even by the act of just opening and then re-saving the file, you're re-compressing your JPEG.

[Jayell]

Even by the act of just opening and then re-saving the file, you're re-compressing your JPEG.

I think I already knew that. Just hate the idea of having to go back to the psd every time to change something that only affects the jpg. Guess I'll have to find a slightly different workflow for this project.
Thanks, Steve.

[Dave McElderry]

That's what the modern huge capacity hard drives are for. If I'm editing or creating a graphics file I always have the psd available. If I make a change it happens in the psd first. I agree it's a bit more hassle, but no worries about the resaves.

[mark hansen]

UMMM looks like I'm in the same boat. As I run my high res photos through photo shot to get the pix down to 1000, would it be better to save them to PSD instead back to jpg. I'm thinking because of this string, if I reopened them from CS3 into Photoshop, I wouldn't lose anything.

Will the larger file size of the PSD hurt CS3 (longer rendering, process instability etc ) vice keeping them in JPG?

Mark

[Jayell]

That's what the modern huge capacity hard drives are for.

Oh, you mean so that I can litter my hard drive with useless and confusing stuff, wondering why I have all these files? I always keep the psd, but unfortunately almost every time I'm saving to jpg, I'm reducing the pixel dimensions, so I was trying to avoid saving TWO of each one. Well, piffel!

[Bob]

You can change the metadata in Bridge without recompressing a jpg.

Alternately, you can save your file in .PNG format which is lossless -- you can resave it as many times as you want in Photoshop without degrading the image. Just be sure your image mode is RGB color and not Indexed or grayscale (which would produce an indexed PNG file similar to a GIF).

And, of course, PSD files are lossless too.

[Jayell]

You can change the metadata in Bridge without recompressing a jpg.

Bingo! That worked. I should have known .. Bridge does sooooo much stuff. Bob saves the day again.

Just be sure your image mode is RGB color and not Indexed or grayscale (which would produce an indexed PNG file similar to a GIF).

I'm not quite following this, Bob. Could you explain further? Because it seems like a lot of my stuff comes into Photoshop indexed, which I don't really understand.

[Bob]

...it seems like a lot of my stuff comes into Photoshop indexed, which I don't really understand.

That sounds strange. Other than GIF, most files are RGB mode these days. What sorts of files are coming in indexed?

[Jayell]

What sorts of files are coming in indexed?

Without doing an exhaustive search, they probably ARE gifs, Bob. I do a lot of work with small graphics. But I'll keep my eye on it to make sure that's all it is.

[John 'twosheds' McDonald]

FWIW my Photoshop workflow is original pics from camera imported as RAW files. Any subsequent work is saved as .psd files.

Anything used in videos is batch converted for size in Photoshop then saved in the video working directory.

[Jayell]

Anything used in videos is batch converted for size in Photoshop then saved in the video working directory.

I've got to get back to this. I used to have files in specific working directories, but my videos tend to go on (some for years), and I'll use the same photos in different videos, so I felt like I had too many copies around .. but NOT doing that has caused lots of issues. And for now, I have plenty of hard drive space.

[mark hansen]

I keep my photos from my camera on a seperate external HD (backed up on a second HD). They are in folders by the date they were shot and tagged in Bridge so I can find them. Photos I put in videos are ran through PS to reduce the pix and stored in a video stills folder as part of the project. I usually create a temp action to SaveAs in a seperate folder. When the project is over, those get deleted when the project folder is deleted, keeping the orginal file untouched.

The question for me when I run them to PS, its sounds like I should save a PSD rather than JPG in the project folder.