What is the best way to achieve lossless JPEG quality in Photoshop? Is setting the quality of the file to "maximum" essentially lossless? I've been using .png files a lot more, but some of my clients still don't welcome that format. Thanks!

no jpg save is lossless.

I thought I heard that some types of JPEGs are lossless. Was I misinformed?

If you look up jpeg in wikipedia it's described as

a commonly used method of compression for photographic images




but further down states that there are

variations on the standard baseline JPEG that are lossless




which was a surprise to me.

I believe so, but one may not see the effect at the higher resolution rates until you save it numerous times, and have it enlarged a lot. Just what I heard so don't take it as fact.

I think the term "Lossless" in combination with "Jpeg" can be found in lossless rotation.

This can, for instance be done with Irfanview. Rotation is simply moving the discrete pixels around without parsing an subsequent recompiling them. (correct me if I'm wrong).

Rob

<http://en.wikipedia.org/wiki/JPEG-LS>

If you use the maximum quality/minimum compression settings and your clients
are simply viewing your files there will be no significant loss of quality
for the intended use of simply reviewing an image. They will see a very high
quality image from their viewpoint.
Clearly jpeg is the wrong format for storing images that will be further
processed, used for purposes like offset printing or need to be archived in
pristine quality.

jpeg2000 does lossless, but it's not exactly the same as jpeg

Dave_Jansen@adobeforums.com wrote:
> What is the best way to achieve lossless JPEG quality in Photoshop? Is setting the quality of the file to "maximum" essentially lossless? I've been using .png files a lot more, but some of my clients still don't welcome that format. Thanks!


http://www.hpl.hp.com/loco/

download the photshop plugin

r

See this link on jpeg.org
lossless or lossy jpeg.

<http://www.jpeg.org/faq.phtml?action=show_answer&question_id=q404fa5e2 9aeb6>

Ed

Lossless JPEG is a bit of a misnomer. It is part of the original JPEG standard (Annex H to CCITT Recommendation T.81), but it does not use the compression technique (DCT compression) that is the primary feature of JPEG, often referred to as JPEG compression. Instead it uses either Hoffmann or arithmetic coding. It also can be used for 16-bit image data, unlike the lossy JPEG format. I'm not sure what the point was to it, given that there are other lossless compressed and non-compressed formats, such as TIFF. It has rarely been implemented, probably for that very reason. According to the Wikipedia entry for Lossless JPEG <http://en.wikipedia.org/wiki/Lossless_JPEG>, it has been used in some medical imaging applications and is used in, of all things, DNG and some cameras' RAW formats (perhaps the encoding technique is used, rather than the image format). There two other techniques mentioned there: JPEG-2000, mentioned above, and JPEG-LS, which is nearly lossless.

Michael,

his name is Huffman.

Best regards --Gernot Hoffmann