Jpeg vs jpeg 2000

Homo Lupus · March 24, 2011

I am using CS-5. When saving raw images that have been processed I would like to save them as JPEGs but often the only option in the Save As mode is JPEG 2000.
What is the difference in the two and can I do anything in processing images that would allow me to have a choice in saving the image as a JPEG or JPEG 2000 or JPEG F?
CS-5 Help does not seem to be helpful in finding this answer.
Best to all,
Homo Lupus

pathfinder · March 24, 2011

Welcome to dgrin!!

I was going to say reduce your image bit depth to 8 bits, from 16 bits, but I find jpg is available in my Save As dialogue box in CS5 for 16bit images too.

Are there layers in these images, or have they been flattened? They are not Smart Objects are they?? I keep thinking you may be trying to save a 16bit layered image, and jpgs are 8 bit single layer images.

jpeg 2000 uses a different encoding algorithm than jpgs, something about wavelet based, rather then discrete cosine transform yada yada - http://en.wikipedia.org/wiki/JPEG_2000 - will explain it much better than I can or even want to.

The idea was that it is more efficient, and less lossy, but not everyone agrees with that either - http://www.vterrain.org/Imagery/JP2K/

Does anyone routinely use jpeg 2000? I must confess I have been to at least a dozen photo or print workshops, and have met no one who admits to using it.

Here is a discussion on John Nack's blog about jpeg2000, and there are a few folks who do use it, but the blog post is three years old, so...

Homo Lupus, I see you have spent some time chasing wolves in Yellowstone. I am quite impressed, as I have an idea just how much work is involved in getting as close as you have in some of your images in the snows in Yellowstone. Folks should check out your galleries, you have some very lovely work there - http://www.pmwm.smugmug.com/

And you went to Svalbard!! And saw polar bears up close and personal, too. And Kenya also! Wow.

I just finished reading David Robert's book "Four Against the Arctic: Shipwrecked for Six Years at the Top of the World" about his trip to Svalbard for information about some Russian hunters marooned on Svalbard for 6 years, without weapons or provisions, in the 18th century.

MarkR · March 24, 2011

Jpeg2000 is probably technically superior, but never found widespread support.

Are you able to save as TIF or PSD?

Richard · March 24, 2011

pathfinder wrote: »

Are there layers in these images, or have they been flattened? I keep thinking you may be trying to save a 16bit layered image, and jpgs are 8 bit single layer images.

CS5 takes care of that gotcha as well. But I think you're on the right track--something in the document that JPG can't handle

.

MarkR · March 24, 2011

Interestingly, JPEG2000 support was removed from baseline Photoshop back in CS2 -- although it's still available as an installable component.

EDIT: I'm wrong. They put it back in CS5 for whatever reason. Sorry.

pathfinder · March 24, 2011

Marc, you should have left your post that you deleted, I think it is quite pertinent about 8 bit vs 16 bit jpgs. I remember having to downsize from 16bits to 8 bits with earlier versions of PS ( not sure which ones ) but yes, CS5 downsizes it for you when you save as a jpg, to 8 bits from 16 bits.

Marc's Post -->: "Pathfinder, quick clarification: Jpeg is always 8 bits. The Photoshop people just got sick of support calls about not being able to easily convert a 16-bit image to jpeg, so they eliminated the extra step of mode-> 8 bit. It was part of their "Just Do It" initiative for CS5, same initiative that gave us a ruler tool that now straightens. . Can't find the linky right now tho.

?"

MarkR · March 24, 2011

pathfinder wrote: »

Marc, you should have left your post that you deleted, I think it is quite pertinent about 8 bit vs 16 bit jpgs. I remember having to downsize from 16bits to 8 bits with earlier versions of PS ( not sure which ones ) but yes, CS5 downsizes it for you when you save as a jpg, to 8 bits from 16 bits.

Marc's Post "Pathfinder, quick clarification: Jpeg is always 8 bits. The Photoshop people just got sick of support calls about not being able to easily convert a 16-bit image to jpeg, so they eliminated the extra step of mode-> 8 bit. It was part of their "Just Do It" initiative for CS5, same initiative that gave us a ruler tool that now straightens. . Can't find the linky right now tho. ?"

I'm batting 0.0000 right now-- and I work at an IT help desk for a living!

One thing the original poster should try is to go to mode--> and see what options are selected. He may be in a color mode that is not supported by jpeg.

.

pathfinder · March 24, 2011

I think Marc, Richard and I are in agreement that there is something in the image makeup ( bit depth, color space, number of layers, Smart Objects maybe ??) that is causing CS5 to omit offering jpgs as a choice for saving.

Can the original poster save jpgs from tiffs or pngs, to verify that the CS5 engine has the plug in necessary to save any file as a jpg?

arodney · March 24, 2011

pathfinder wrote: »

Welcome to dgrin!!

I was going to say reduce your image bit depth to 8 bits, from 16 bits, but I find jpg is available in my Save As dialogue box in CS5 for 16bit images too.

JPEG can’t support 16-bit. What Adobe did in CS5 was allow you to save a 16-bit JPEG without changing it first to 8-bit manually. Meaning it will convert from 16-bit to 8-bit then save the JPEG.

pathfinder · March 24, 2011

That's what I thought, Andrew, and CS5 DOES allow saving as a jpg with 16 bit files, but automatically converts them to 8 bits before writing them to disk ( I had forgotten that step although I knew you had to ok that step when the second dialogue box comes up ). As Marc said, previous versions of PS would NOT do that, they required the user to downsize their bit dimension to 8bit, so that the users would be aware of that step.

But the OP says he is NOT offered jpg as an alternative to save as in his CS5, and we have not really answered why he cannot yet, I think.

MarkR · March 24, 2011

If I move an image into L*a*b* mode, I lose the ability to save as JPEG, but JPEG2000 is available as a format. (Although TIFF is also available.) I'm thinking that might be the problem. (If not that, then possibly one of the other non-RGB modes.)

arodney · March 24, 2011

MarkR wrote: »

If I move an image into L*a*b* mode, I lose the ability to save as JPEG, but JPEG2000 is available as a format. (Although TIFF is also available.) I'm thinking that might be the problem. (If not that, then possibly one of the other non-RGB modes.)

JPEG only supports RGB color model.

I can’t fathom why anyone would want to save out an 8-bit Lab file, let alone one that had JEPG compression. Ouch, major data loss.

pathfinder · March 24, 2011

"Ours is not to reason why..........."

pathfinder · March 24, 2011

MarkR wrote: »

If I move an image into L*a*b* mode, I lose the ability to save as JPEG, but JPEG2000 is available as a format. (Although TIFF is also available.) I'm thinking that might be the problem. (If not that, then possibly one of the other non-RGB modes.)

Thanks, Marc, I suspect you are correct.

Homo Lupus · March 24, 2011

Jpeg VS Jpeg 2000
Thank you all for contributing. The bottom line is I believe I have been shortcutting my work flow and creating images that will fall into the jpeg 2000 realm.
I can not work at the moment but I will attempt to recreate the situation again and with your good counsel I believe will find and solve the problem.

As Yogi Bera once said. If you don't go to your friends funeral they may not come to yours." Thanks for the good support friends.

And thank you for the kind words on the images.

Adios, Homo Lupus...

Homo Lupus · March 25, 2011

JPEG vs JPEG 2000
Ah Ha ! The problem was in two parts, which I missed. I had left an image in LAB and forgot to Flatten the file. So thanks again for your help.
You folks gave me some good pointers that turned the old light bulb on.
Problem solved.
Best to all,
Homo Lupus

Jpeg vs jpeg 2000

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