Longshadow Loc: Audubon, PA, United States

JD750 Loc: SoCal

I can see the color difference in the images presented.

I do not pixel peep. I view an image from a normal viewing distance. That is me.

However there is a set of people who do pixel peep. That it how they derive enjoyment from an image. I once saw a man at a VanGogh exhibit walking up to inches away and using a magnifying glass to examine the painting. Ok. If that's how you like to view it then go ahead.

Longshadow Loc: Audubon, PA, United States

Delderby Loc: Derby UK

But you'd get the same answer from 2 and 6. Where would that leave you?

BigDaddy Loc: Pittsburgh, PA

Only if the reason you don't edit jpgs is the quality diminishes each time you edit.

Developers format is a proprietary format that some editors have so you can save your edited file in a loss-less format, and maintain your edits so they can be re-edited after reopening the file. File formats are denoted by file extensions, like .txt, .exe .com, .jpg, .png and so on.

The format for a Photoshop (including PSE) developer file is .PSD. In Affinity Photo it's .AFPhoto. In ACDSee it's .ACDC. Interestingly, Affinity Photo allows you to save in .PSD format if you want. As I said, these are proprietary formats so not sure how Affinity gets away with it, unless they license the code? You can actually open a PS .psd file in Affinity. Not sure if all the same stuff is preserved. Generally speaking you can only edit the files with the editor that created them. Many viewers will open various formats, particularly .PSD files but they will not preserve the edits, and they can't re-save in the developers format.

To use these when you save your file in the editor, you'll get a choice of formats to save in. All you need do is select one of the above if using any of the 3 editors I listed. Other editors I'm not familiar with, like Gimp, but they likely have a production format as well. Lighter weight editors, like FastStone don't.

DAGS on the extensions I listed and you should get more information on each type of format.

BebuLamar

How do you know for sure it's the average? It's likely but not sure.

Ysarex Loc: St. Louis

You don't need a magnifying glass to see it in Davyboy's photo here: https://www.uglyhedgehog.com/t-308167-1.html#5179241 It's easy to see even in the thumbnail.

I did everything right to keep the degradation to a minimum editing that JPEG -- including choosing the right tools in PS. I could have edited it like Davyboy's squirrel but that wouldn't have been honest. I see that kind of damage all the time looking at photos on these various forums.

davyboy Loc: Anoka Mn.

That’s funny that you chose that photo. It is an old photo but probably the most commented on.

Ysarex Loc: St. Louis

Big Daddy was referring to the proprietary formats of the various editors such as Photoshop's PSD format.

If you're shooting and processing raw images you should pay attention to your overall raw workflow. It may not be entirely possible given what you have to accomplish but if you can work with a parametric raw processor and keep you editing confined to that application you can gain a couple advantages -- may or may not be meaningful to you. I process a lot of images and I value the goal of keeping my raw workflow 100% non-destructive and non-linearly re-editable. To do that you have to work parametrically and avoid using a raster editor like PS, Affinity, etc. as they will often add a destructive element to your work. NOTE: By destructive in this context I'm not referring to preserving the original image but rather to not introducing an edit into your image that would force you to redo your previous work. In that context for example Affinity Photo is a forced destructive editor in a raw workflow.

Another advantage to maintaining a parametric raw workflow is a huge saving in disk storage as those RGB image files like PSD and TFF and quite large.

srt101fan

Nothing wrong with a closeup examination of Van Gogh's brush strokes. But if that"s the only way you look at the painting you are really missing out....

Longshadow Loc: Audubon, PA, United States

But given only one image to view, there would be no difference.

BigDaddy Loc: Pittsburgh, PA

Your monitor and your printer are 8 bits. If they weren't, you, and your wallet would know, even if the pictures looked eerily the same....

Longshadow Loc: Audubon, PA, United States

Thanks.
To me they're monitors.

BigDaddy Loc: Pittsburgh, PA

Your imagination is working great.
Jpg compression works by combining colors your eyes can't differentiate, then encoding them for compression. Most (all) camera's produce jpgs out of it's raw data, and if the raw data is good, the jpg will be good.

The more compression you use, the wider the variance will be combined. Also, each time you re-compress the same jpg, it will combine more data, and eventually you will be combining colors that actually can be distinguished by the human eye. For this reason you generally would not re-compress the same jpg file over itself. With low compression values, you can do this quite a few times w/o visible affects, but in general, it's a bad practice so keep your original original, and save complicated edits in a developers file format that is not compressed, and preserves your edits for further work.

Ysarex Loc: St. Louis

JPEG works by taking similar color pixels and making them the same color in order to create compressible redundancy. Human eyesight has no trouble differentiating the colors that the JPEG algorithm changes into the same color. JPEG succeeds by making many small changes at the pixel level which are swamped by the overall image resolution.

No. The raw data can be good, even excellent and the JPEG can nonetheless completely suck. How good the JPEG is depends on the processing capability of the camera's software. Camera processing software often makes bad JPEGs from good raw data.

In fact most camera processing software will invariably make bad JPEGs from the best raw data. To get good JPEGs from the camera it's often necessary to compromise the raw data to a degree.

As noted, human eyesight can distinguish the colors that the JPEG algorithm changes to same colors -- at all JPEG compression levels.

This is a non-issue. Just don't repeatedly re-compress a JPEG. It's also a non-issue in that the damage done from re-compression is slight and much less than the damage done by making substantial changes to the tone/color of the image which can not be avoided. Minor to medium edits to JPEGs are successful for most people because the damage done is swamped in the resolution of the image and as such not normally visible.