OK, I've edited a lot of images over the years (I use Paint Shop Pro) but never really thought too much about this and I'm obviously missing something. I'm working on some photos to be 300 dpi at 4x6 and 5x7 inches. But even though I've set them to no compression (1) when they're saved, the jpgs are coming out at much less that what I would think they should. For example a 4x6 image at 300 dpi should be 2.16 MB, right? (1200 x 1800 px). My jpgs are coming out at under 1 MB. Maybe another setting somewhere?

Thanks, Diana

Diana,
the opened file size is different than the saved file size because a jpeg is a compressed file format. For example, a 4X6 image saved as a .tif file at 300 dpi is 6.18 MB. The same file saved as a jpeg is 509 KB in saved file format (not opened) #8 quality setting in PS. The good news about jpegs is that they take up less space as saved files; the bad news is that if you open and close them a lot, they lose image detail because the algorithm for compressing the file loses information each time it's opened and closed.

For that reason, most people save their images for long-term storage as tiffs which use loss-less compression algorithms i.e. you can open and close the file as much as you like and you don't lose any data.

When we send our advertising files to publications, we send them as jpegs for transmission efficiency but ask the publication to open the file and re-save it as a CMYK tiff. That way, the archive copy will always be intact.

Hope that helps.

Jim

So if I open the original jpg file, then make an edit but save it as a psp, and the original file is not resaved, it would not lose anything, right? I have thought about trying raw just to have the extra flexibility to correct weaknesses in an image.

Thanks again, Diana

Diana,
there are advantages and disadvantages to each approach. Some folks on this forum shoot jpegs exclusively -- Julie Poole for example -- and her images are outstanding. So the question is more "what are you going to do with the images" than whether RAW or jpeg is better.

In a typical workflow, you open the images for initial viewing, select the ones you want to keep and/or edit and then resave them to a separate folder. Then you open them again, edit and enhance them, and save them probably to another folder. When you print them yourself or have them printed, you open and close those images again. Each time you do it, the image is degraded to some extent. You can avoid that issue to some extent by saving the edited final version as a .tif file which is your archive copy. That way whenever you need that image for printing, posting, etc., you simply open the .tif and resave it as a jpeg to send to your printer or posting host computer. That last jpeg is virtually as good as your archived .tif.

In RAW, you save the original RAW image once you've made your initial cull and it is a file that has received no processing at all. Which means that as software technology improves and allows us to get more detail out of our original RAW files, you'll be able to do so. I have RAW files that I took with my D30 (not 30D, the original Canon prosumer camera) and when I process them in PhotoShop CS4, those images look as good as anything coming out of a current DSLR -- except they are only 3.4 mpx.

In RAW, my workflow is to review all the RAW images in Bridge and select the files I want to work on. I save those in a separate folder as tiffs. Once they are all edited and finalized, I resave the tiffs into my Final folder. When I send them out for proofs, I open them, save them as jpegs and send them to the lab. When I post them to my website, I open them, resave them as smaller jpegs or gifs and save them to a separate folder. My original RAW files are archived and I have the final edited version saved in a non-destructive file format for use whenever I need them.

As Geo says, shooting RAW adds complexity to the workflow and eats up storage space. But, for me, it provides a long-term flexibility that I don't get with jpegs and it allows me to retain the original image quality for as long as I store the RAW files. That's important to me. I have folks calling me virtually every month asking for a print of an image I took at a dog show 5 years ago. The prints I make today with those files are better than the prints I made 5 years ago.

One additional advantage of RAW is the ability to correct for color-casts very easily in the initial edit in Adobe Camera Raw. The images you just took of the cats with the slightly magenta background tinge would be corrected with one click in ACR.

Hope all this stuff helps.

Jim

Try it for yourself. Take a copy of a JPEG and open it and save it. Then open it again and look at a 100% crop. You won't see any difference. Do it 4 or 5 more times and you'll start to see a real problem. I shoot RAW because I like the flexibility and I can recover from my mistakes and still have a publishable image. If I blow a highlight in a JPEG there is no getting it back...in RAW you can.

You definitely should save your edited files in TIF or a lossless format so that you do not get into 3rd or 4th or 5th generation JPGs.

Uffda! Thanks everyone, I'm going to read through these replies more through the day, there's a lot of great info here. I will definitely start saving my first round of open images in tif from now on. I know space is going to be an issue but that will always be the case, right? I do have a couple more questions so will shoot those out later today. Thanks again!
Diana