JPEG quality

When you save an image under Photoshop you get the JPEG options menu. This offers you "Image Options" and "Format Options". Under "Image Options" you can
specify a number ranging from 0 (minimum) to 12 (maximum). I have a Nikon Coolpix 8700, and have been in the habit of saving any pictures I edit at '9' - "you don't want to lose any quality" --, but have noticed that frequently this gives a substantially larger file than the original.

So I did some tests, and saved a relatively sharp photograph, trimmed to 1080 by 1300, at every quality from 0 to 9. The resulting file sizes ranged fairly evenly from 110KB to 620KB. When I printed the files with qualities 0, 3, and 6, at 300 dots per inch (corresponding to an 8" by 10" print of the original photo) compression artefacts were visible, but not obvious, at 0, just visible at 3, and pretty well invisible at 6 At 150 dots per inch, the artefacts were quite noticeable at 0, and just noticeable at 3. On the screen they were obvious at 0, and noticeable at 3.

Under "Format Options"you are offered Baseline ("Standard"), Baseline Optimised,
and Progressive, with "Standard" the default.

Is there any generally accepted setting for the quality? And is there any good reason to change the format options from "Standard"?

James McNangle

James, The image options and format options are very useful tools to adjust the file size and quality once you are finished with it. But, until you are sure that you will not need to edit the image further you might want to consider an uncompressed image format like a .tiff. Saving and resaving .gif images will progressively reduce the quality of the image.

Whether you are using the image for print or for web will have a direct impact on what settings you should use. Trying the different settngs is the best way to get a feel for what you will need for each type of job.

Hope this helps a bit. Not sure if I actually answered your question.

To correct an error - I referred to a .gif file type, but obviously meant to say .jpg.

Sorry for any confusion.

In article ,
James McNangle wrote:

When you save an image under Photoshop you get the JPEG options menu. This offers you "Image Options" and "Format Options". Under "Image Options" you
can
specify a number ranging from 0 (minimum) to 12 (maximum). I have a Nikon Coolpix 8700, and have been in the habit of saving any pictures I edit at '9' -
"you don't want to lose any quality"

What you do not understand is that evven if you re-save at 9, you **do**lose quality.

If you open a JPEG and re-save it, you lose quality. Every time. If you open it again and save it again, you lose more quality. If you open it and save it again, you lose still more quality.

JPEG is lossy. Always. When you save a JPEG you lose quality, period.

For this reason, you should never edit and re-save a JPEG. Open the picture from your camera, do your edits, and then save it in a lossless format like TIFF. If you make more edits, go back to the TIFF.

--, but have noticed that frequently
this
gives a substantially larger file than the original.

So? Why are you worried about it? Do you have an antique 486 computer with a 2 gigabyte hard drive?

Hard drives are cheap. Blank CDs are cheap. Blank DVDs are cheap. Why degrade your images in order to save a few kilobytes?

So I did some tests, and saved a relatively sharp photograph, trimmed to 1080 by
1300, at every quality from 0 to 9. The resulting file sizes ranged fairly evenly from 110KB to 620KB. When I printed the files with qualities 0, 3, and
6, at 300 dots per inch (corresponding to an 8" by 10" print of the original photo) compression artefacts were visible, but not obvious, at 0, just visible
at 3, and pretty well invisible at 6 At 150 dots per inch, the artefacts were
quite noticeable at 0, and just noticeable at 3. On the screen they were obvious at 0, and noticeable at 3.

You may find that as you become more experienced, you learn to recognize JPEG degradation more. You may not find the artifacts objectionable now, but you may in the future.

And there is no reason to accept the degradation at all. I assume that at least some of these pictures must be important to you, and I assume that you can't always go back and re-shoot them...so why lose quality if you don't have to? It is not necessary to re-save a JPEG at all. Just save a TIFF--the amount of space it occupies surely cannot be all that great a catastrophe!

Under "Format Options"you are offered Baseline ("Standard"), Baseline Optimised,
and Progressive, with "Standard" the default.

"Standard" means "the original JPEG specification." "Optimized" means
that the JPEG data is optimized for file size; it gives a smaller file for exactly the same quality. "Progressive" means "save the JPEG so that when a browser views it, the user will see a fuzzy low-res image first, then a high-res image." "Progressive" is designed for sending very, very large JPEG files over a slow telephone line--the user sees the fuzzy version quickly, so he can get an idea of what the picture is and can cancel the download if he wantss.

Is there any generally accepted setting for the quality? And is there any good
reason to change the format options from "Standard"?

Yes, there is a good reason to use Optimized instead of Standard; it makes the file smaller, and if you're worried about file size, that's a good thing.

But unless you are using some antique, primitive computer with a tiny hard drive and no CD recorder, there is no real reason to save JPEG at all. Forget JPEG; you don't need to degrade the quality of your pictures. Save as TIFF.

--
Art, photography, shareware, polyamory, literature, kink: all at http://www.xeromag.com/franklin.html

The 8700 can yield very high quality images.
As such, and if your are using Photoshop, you are cheating yourself by not learning to use your tools properly.
After you open your in camera made jpeg for the first time save it in a lossless format, preferably tif or the Phothsop psd format. Learn to use Photoshop: work in lossless layers and save in the psd format. The bottom layer is your untouched original and you can always delete what layers you do not like or start over from scratch.
I do not know if the 8700 can save images in Nikon's raw format. If it can save raw images learn how to use the raw format instead of jpeg, learn how to process your images in Photoshop and print with color management and you will see a whole new world of photograrphy open up before your eyes. You will be able to do more in a few minutes than the greatest wet darkroom color printer could ever accomplish.

On Tue, 29 Nov 2005 18:26:20 +1100, James McNangle
found these unused words floating about:

When you save an image under Photoshop you get the JPEG options menu. This offers you "Image Options" and "Format Options". Under "Image Options" you can
specify a number ranging from 0 (minimum) to 12 (maximum). I have a Nikon Coolpix 8700, and have been in the habit of saving any pictures I edit at '9' - "you don't want to lose any quality" --, but have noticed that frequently this gives a substantially larger file than the original.

So I did some tests, and saved a relatively sharp photograph, trimmed to 1080 by 1300, at every quality from 0 to 9. The resulting file sizes ranged fairly evenly from 110KB to 620KB. When I printed the files with qualities 0, 3, and 6, at 300 dots per inch (corresponding to an 8" by 10" print of the original photo) compression artefacts were visible, but not obvious, at 0, just visible at 3, and pretty well invisible at 6 At 150 dots per inch, the artefacts were quite noticeable at 0, and just noticeable at 3. On the screen they were obvious at 0, and noticeable at 3.

Under "Format Options"you are offered Baseline ("Standard"), Baseline Optimised,
and Progressive, with "Standard" the default.

Is there any generally accepted setting for the quality? And is there any good reason to change the format options from "Standard"?

James McNangle

Probably not as you don't seem to care about further loss by saving AGAIN in ..jpg!

"bmoag" wrote:

The 8700 can yield very high quality images.
As such, and if your are using Photoshop, you are cheating yourself by not learning to use your tools properly.

This strikes me as a bit extreme. Fine quality jpegs from this camera are almost indistinguishable from tif or raw images, even at the pixel level.

After you open your in camera made jpeg for the first time save it in a lossless format, preferably tif or the Phothsop psd format.

Or when you re-edit start over again from the original jpg. Keep the original image, and use it as if it were a "digital negative".

Learn to use Photoshop: work in lossless layers and save in the psd format.

This is not just an issue of learning, but of workflow designed to meet ones needs. Sinde I take a lot of pictures, and seldom spend more than a minute on each one, I don't save as a psd unless I expect to come back and make minor adjustments later. It's just as easy to start over.

The bottom layer is your untouched original and you can always delete what layers you do not like or start over from scratch.

True, but it is not always necessary, or desirable to spend the time and storage to be able to do this, particularly if you take hundreds of images and spend a brief amount of time, if any, on each one.

I do not know if the 8700 can save images in Nikon's raw format. If it can save raw images learn how to use the raw format instead of jpeg, learn how to process your images in Photoshop and print with color management and you will see a whole new world of photograrphy open up before your eyes. You will be able to do more in a few minutes than the greatest wet darkroom color printer could ever accomplish.

The 8700 supports raw. Raw images are an important addition to our capabilities as photographers. IMHO, although there are some important advantages to raw files, people are over-reacting when they advocate taking every single image in raw format. Raw offers no starting advance in quality over tiff, or even fine jpeg.

That said, there are photographers who will go to any lengths in pursuit of infinitesimal quality improvements. I applaud this. As Stieglitz said "I am an idolater of perfection", and likewise I am an admirer of the work of such people.
--

Mike Russell
www.curvemeister.com

On Tue, 29 Nov 2005 18:53:20 GMT, "Mike Russell" found these unused words floating
about:

This is not just an issue of learning, but of workflow designed to meet ones needs. Sinde I take a lot of pictures, and seldom spend more than a minute on each one,

ROTFLMAO ... !!!

The 8700 supports raw. Raw images are an important addition to our capabilities as photographers. IMHO, although there are some important advantages to raw files, people are over-reacting when they advocate taking every single image in raw format. Raw offers no starting advance in quality over tiff, or even fine jpeg.

That said, there are photographers who will go to any lengths in pursuit of infinitesimal quality improvements. I applaud this. As Stieglitz said "I am an idolater of perfection", and likewise I am an admirer of the work of such people.

Whether jpeg or tiff, every digital image taken with a digital camera got to be in its proprietary raw initially. Theoretically, raw is in its worst stage visually. It needs to go through an "interpolation" process, some luminance, colors and several other adjustments before converting to your preferred image format. The question is the above mentioned tasks are done by the camera built-in processor and raw converter program or you the photographer do the post production work with your computer and your raw converter program. The later is preferred regardless of time and effort consumed if you know how to get the best out from the raw but will be backfired if you are incompetent to it. To save the post production works, leave it to the camera to do the tasks by selecting the jpeg or tiff image option before shooting. So which is better? It's analogous to film era when people have the option of sending negative for commercial machine print or custom enlargement print. The choice is yours depending on your experiences.

In article ,
says...

In article ,
James McNangle wrote:

[SNIP]

"Standard" means "the original JPEG specification." "Optimized" means
that the JPEG data is optimized for file size; it gives a smaller file for exactly the same quality. "Progressive" means "save the JPEG so that when a browser views it, the user will see a fuzzy low-res image first, then a high-res image." "Progressive" is designed for sending very, very large JPEG files over a slow telephone line--the user sees the fuzzy version quickly, so he can get an idea of what the picture is and can cancel the download if he wantss.

[SNIP]

Tacit,

A quick question regarding the "Progressive" spec for JPG. At one time, MACs had a problem with Progressive JPGs. This might well have been a limitation of the "common" image viewers on some, but I had several clients on MAC platform, who asked that this spec not be used (some years back). Is there any limitation nowadays? I've also seen Progressive used on Web sites, to do, just as you describe. As the image will be viewed via browser, is there any platform incompatability now?

Thanks for the info,
Hunt

In article , (Hunt)
wrote:

A quick question regarding the "Progressive" spec for JPG. At one time, MACs had a problem with Progressive JPGs. This might well have been a limitation of
the "common" image viewers on some, but I had several clients on MAC platform,
who asked that this spec not be used (some years back). Is there any limitation nowadays?

As far as I know, no. All the major Mac browsers, for both OS X and OS Classic, have no problems whatsoever rendering progressive JPEG images, and I haven't seen any other application which has trouble with progressive JPEGs either.

--
Art, photography, shareware, polyamory, literature, kink: all at http://www.xeromag.com/franklin.html

J. A. Mc. wrote:

On Tue, 29 Nov 2005 18:53:20 GMT, "Mike Russell" found these unused words floating
about:

This is not just an issue of learning, but of workflow designed to meet ones needs. Sinde I take a lot of pictures, and seldom spend more than a minute on each one,

ROTFLMAO ... !!!

Have you ever used a high quality digital camera, J.A. Mc? Maybe Mike uses a high end camera in a controlled studio environment with accurate metering and focusing? All of my studio images come off the camera so good there is virtually nothing to adjust on computer, other than a little sharpening and maybe a tiny tone curve tweak. Occasionally some colour balance adjustments. That is something I had to get used to after scanning film/using cheaper digital cameras, where there were always lots of adjustments to be made.

Brian.

In article ,
says...

In article , (Hunt)
wrote:

A quick question regarding the "Progressive" spec for JPG. At one time,

MACs

had a problem with Progressive JPGs. This might well have been a limitation of
the "common" image viewers on some, but I had several clients on MAC platform,
who asked that this spec not be used (some years back). Is there any limitation nowadays?

As far as I know, no. All the major Mac browsers, for both OS X and OS Classic, have no problems whatsoever rendering progressive JPEG images, and I haven't seen any other application which has trouble with progressive JPEGs either.

--
Art, photography, shareware, polyamory, literature, kink: all at http://www.xeromag.com/franklin.html

Thanks for the response and info. As stated, this was quite a few years ago, AND I don't know if it was confined to just two clients' systems (or their operators).

Hunt

Brian wrote:

J. A. Mc. wrote:

On Tue, 29 Nov 2005 18:53:20 GMT, "Mike Russell" found these unused words floating
about:

This is not just an issue of learning, but of workflow designed to meet ones needs. Sinde I take a lot of pictures, and seldom spend more than a minute on each one,

ROTFLMAO ... !!!

Have you ever used a high quality digital camera, J.A. Mc? Maybe Mike uses a high end camera in a controlled studio environment with accurate metering and focusing? All of my studio images come off the camera so good there is virtually nothing to adjust on computer, other than a little sharpening and maybe a tiny tone curve tweak. Occasionally some colour balance adjustments. That is something I had to get used to after scanning film/using cheaper digital cameras, where there were always lots of adjustments to be made.

Brian.

Besides that Mike is the author of the wonderful CurveMeister plugin. I use that for my color corrections and love it. It really does let you correct the color in seconds.

Most of my pictures are edited in about a minute too. I use CurveMeister for color adjustment, Noise Ninja for noise abatement, and Focus Magic for sharpening. That is my standard workflow for most of my pictures. A minute or maybe two would be about right.

Clyde

At the risk of flying in the fact of Usenet custom, I have a couple of things to say that actually address James's original post.

"James McNangle"wrote:

When you save an image under Photoshop you get the JPEG options menu. This
offers you "Image Options" and "Format Options". Under "Image Options"
you can
specify a number ranging from 0 (minimum) to 12 (maximum).

I have a Nikon
Coolpix 8700, and have been in the habit of saving any pictures I edit at '9' -
"you don't want to lose any quality" --, but have noticed that frequently this
gives a substantially larger file than the original.

The 8700 is a great camera, strictly from a quality standpoint, it competes favoably with older generation DSLRs. I use mine almost every day and the quality is amazing.

The Fine quality setting on this camera corresponds to about a 9 or 10 quality setting in Photoshop.

Many editing operations, including contrast and color enhancement, sharpening, and even image rotation or resampling, can result in more apparent fine detail in an image, and result in a larger compressed jpeg file.

So I did some tests, and saved a relatively sharp photograph, trimmed to 1080 by
1300, at every quality from 0 to 9. The resulting file sizes ranged fairly
evenly from 110KB to 620KB. When I printed the files with qualities 0, 3, and
6, at 300 dots per inch (corresponding to an 8" by 10" print of the original
photo) compression artefacts were visible, but not obvious, at 0, just visible
at 3, and pretty well invisible at 6 At 150 dots per inch, the artefacts were
quite noticeable at 0, and just noticeable at 3. On the screen they were obvious at 0, and noticeable at 3.

Kudos for doing your own testing. Only one person in 500 will actually test whether what they are asking about produces a visible difference in the image or not. In doing this, you have essentially answered your own question, but there are a couple of other things relating to jpeg quality that might interest you.

The most familiar form of jpeg artifacting is the "mosquito" artifacts at the corners of images. This name came about, legend has it, because of the appearance of these artifacts in video - they flicker and look like hovering mosquitos. There is another, subtler, price to pay for jpeg compression, and that is color quantization. Large areas of flat color, a GM Color Checker for example, will have colors that change considerably from their original values when saved as jpeg.

Of even more concern to photographers is the tendency of even high quality jpegs toward banding. Even at fine quality jpeg, a sky or other finely shaded subject will show banding due to quantization that goes away when you shoot the same shot as a tiff or raw file.

Screen displays tend to show up banding and artifacts in the highlights and midtones, while a print will tend to show problems in the shadows.

For a dramatic demonstration of how a jpeg affects image quality, save and re-load it as a jpeg. After 20 or 30 repetitiions, the image is barely recognizeable.

Under "Format Options"you are offered Baseline ("Standard"), Baseline Optimised,
and Progressive, with "Standard" the default.

Is there any generally accepted setting for the quality? And is there any good
reason to change the format options from "Standard"?

For pictures I really care about, I will use raw format. The greater number of images, including some that I use for large images, are in fine jpeg. If I'm going to make a large print of 13x19, I start from a fine jpeg or raw, and save all my intermediate results as a psd file.

The vast number of my images, however, are people pictures and postcard-style travel images. These are the ones that I spend a minute or less on for color correcting. <plug> People pictures require, above all, good skin tones, and for that I use the skin tone pinning of Curvemeister. Only 23 shopping days 'til Christmas! </plug>

BTW - my thanks to those who came to my defense in the face of James's joke about my spelling error, and I particularly appreciate Clyde's kind words about Curvemeister. Comments like that make my day, for a week. ---

Mike Russell
www.curvemeister.com

Clyde wrote:

Brian wrote:

J. A. Mc. wrote:

On Tue, 29 Nov 2005 18:53:20 GMT, "Mike Russell" found these unused words floating
about:

This is not just an issue of learning, but of workflow designed to meet ones needs. Sinde I take a lot of pictures, and seldom spend more than a minute on each one,

ROTFLMAO ... !!!

Have you ever used a high quality digital camera, J.A. Mc? Maybe Mike uses a high end camera in a controlled studio environment with accurate metering and focusing? All of my studio images come off the camera so good there is virtually nothing to adjust on computer, other than a little sharpening and maybe a tiny tone curve tweak. Occasionally some colour balance adjustments. That is something I had to get used to after scanning film/using cheaper digital cameras, where there were always lots of adjustments to be made.

Brian.

Besides that Mike is the author of the wonderful CurveMeister plugin. I use that for my color corrections and love it. It really does let you correct the color in seconds.

Most of my pictures are edited in about a minute too. I use CurveMeister for color adjustment, Noise Ninja for noise abatement, and Focus Magic for sharpening. That is my standard workflow for most of my pictures. A minute or maybe two would be about right.

Clyde

Hi Clyde,

sounds like you have it all together :-)

It is great to work out a simple, smooth workflow that gets results with a minimum of fuss.

Brian.

bmoag wrote:

The 8700 can yield very high quality images.
As such, and if your are using Photoshop, you are cheating yourself by not learning to use your tools properly.
After you open your in camera made jpeg for the first time save it in a lossless format, preferably tif or the Phothsop psd format. Learn to use Photoshop: work in lossless layers and save in the psd format. The bottom layer is your untouched original and you can always delete what layers you do not like or start over from scratch.
I do not know if the 8700 can save images in Nikon's raw format. If it can save raw images learn how to use the raw format instead of jpeg, learn how to process your images in Photoshop and print with color management and you will see a whole new world of photograrphy open up before your eyes. You will be able to do more in a few minutes than the greatest wet darkroom color printer could ever accomplish.

Hi bmoag,

do you have the 8700 yourself? Having read your post above, I was curious to look up samples from that camera model, as I have an 8.25MP Canon camera myself and wanted to see the difference. I ended up at this page http://www.dpreview.com/gallery/?gallery=nikoncp8700_samples / and I was rather disappointed at the amount of grain in the picture of the Asian lady with the green scalf. You have to open the large file to see what I am talking about.

I have a lot of portrait images where the subject's teeth look so real you could almost touch them, and the abovementioned sample was a typical "digital look" with grain around the teeth (and everywhere else). I am just curious if the samples on that page are not a true reflection of what the camera is really capable of producing.

Regards,
Brian.

Brian wrote:

Clyde wrote:

Brian wrote:

J. A. Mc. wrote:

On Tue, 29 Nov 2005 18:53:20 GMT, "Mike Russell" found these unused words floating
about:

This is not just an issue of learning, but of workflow designed to meet ones needs. Sinde I take a lot of pictures, and seldom spend more than a minute on each one,

ROTFLMAO ... !!!

Have you ever used a high quality digital camera, J.A. Mc? Maybe Mike uses a high end camera in a controlled studio environment with accurate metering and focusing? All of my studio images come off the camera so good there is virtually nothing to adjust on computer, other than a little sharpening and maybe a tiny tone curve tweak. Occasionally some colour balance adjustments. That is something I had to get used to after scanning film/using cheaper digital cameras, where there were always lots of adjustments to be made.

Brian.

Besides that Mike is the author of the wonderful CurveMeister plugin. I use that for my color corrections and love it. It really does let you correct the color in seconds.

Most of my pictures are edited in about a minute too. I use CurveMeister for color adjustment, Noise Ninja for noise abatement, and Focus Magic for sharpening. That is my standard workflow for most of my pictures. A minute or maybe two would be about right.
Clyde

Hi Clyde,

sounds like you have it all together :-)

It is great to work out a simple, smooth workflow that gets results with a minimum of fuss.

Brian.

Ah... It is very rare that someone tells me that I "have it all together", even with a smiley. I'll take it anyway.

It really is a simple matter of turning pro. I do wedding photography. With hundreds of to thousands of pictures from a single wedding, I HAD to work out as smooth a workflow as possible. Otherwise, you get upset brides and loose money.

It isn't perfect, but as a pro you do your best and learn what is "good enough". Also, I shoot plenty of pictures that need a lot more work. The same tools still help a tremendous amount though. Hopefully I have better alternate shots and can throw away the bad pictures, but there are always a few I have to arm twist much harder than I'd like.

Clyde