Making Multiple Adjustments on Original Image

I have seen/heard several times that making more than one adjustment on the original image in Photoshop is a no-no, and I would like to understand more about this and what it does to the image if you do, and how multiple adjustments should be made.

Use layers. I do multiple adjustments all the time and rarely ever touch the original image.

It depends on lots of other factors. First of all, was the orignal image converted from a raw file at 16-bit (PSD or TIFF)?
Also, are the adjustments done on adjustment layers or directly to the image and what kinds of adjustments. Some adjustments are more destructive than others.

What you might have heard is about the generational loss that occurs when repeatedly resaving a JPEG file. Frankly the fears are mostly overblown but its never a good practice to edit an original JPEG...work on copies of the file.

I work on my original RAW files. So I should make a copy (Control+J, right?) to do one adjustment and if I want to do more continue to make copies of that original RAW File?

make copies of raw file, and edit for different part of the picture... like say, one for sky,clothes,skin tone,foreground.... etc then layer them in PS and mask out

Michelle Brooks Photography wrote in post #11854462
I have seen/heard several times that making more than one adjustment on the original image in Photoshop is a no-no, and I would like to understand more about this and what it does to the image if you do, and how multiple adjustments should be made.

Some basic information here about non-destructive editing.

Michelle Brooks Photography wrote in post #11855728
I work on my original RAW files. So I should make a copy (Control+J, right?) to do one adjustment and if I want to do more continue to make copies of that original RAW File?

No.

Once you open a Raw file in Photoshop, the specifics of your approach will be some combination of "best practices" and personal preference. Your Raw file will be "safe" so you can always go back and start over again.

In Photoshop, you will make choices regarding a manageable file size and particular techniques that either preserve your original background layer and your individual adjustments on separate layers or take actions to keep things simpler and keep file sizes down.

A typical "best practice is to do the "keep the original intact and the adjustments on separate layers" approach. But, I've seen very good photogs and Photoshop "gurus" who aren't so picky -- they will use techniques where they will "flatten" an image at some point "getting rid of the original background layer" and then go on to do more work, or merge several adjustent layers -- all of which goes "against the grain" but when they are confident that they are producing what they consider a good result, and at the sae time know that they can always go back to the Raw file and "start from scratch" then they can be as bold as they want!

I'd say do as much as you can using individual adjustment layers and only using image "copy" layers when you have no choice. As you are learning, I'd advise not doing things like flattening initially -- take your time to master your techniques and learn to work with your tools, things like layer effects, and whatnot. In time, well, you are the boss of your own workflow and you can ake choices depending on how confident you are in your skills!

Editing is always destructive and the effect of successive edits is cumulative. Apply a strong curve to an 8 bit image and watch the histogram turn into a comb. The spaces between the "teeth" are lost tonal values. But this is almost always a problem only of 8 bit editing because at best 8 bit has only 256 levels. Destroy a bunch of them and you won't have many left. 16 bit editing (as P.M. noted) is much safer because you can start with 65+ thousand . Throw a lot of them away and you still have more than enough. RAW editing is done in 14 bits, 16 ,384 levels, so it is very safe also. The rule "Anything that can be done in RAW, should be done in RAW" is doubly true if the secondary editing will be in 8 bit.