New version of JPEG developed in Leipzig

[CAcreeks]

... Unfortunately DNG is not widely supported by camera makers.

Why do you use the word "unfortunate" here?

Is it because you want all camera makers to use the same format, and if so, why?

I really don't see why lossless JPEG would be worse than DNG. There is no reason photographers need to have photon counts in their images, is there?

 

[canonagain123]

... Unfortunately DNG is not widely supported by camera makers.

Why do you use the word "unfortunate" here?

Is it because you want all camera makers to use the same format, and if so, why?

I really don't see why lossless JPEG would be worse than DNG. There is no reason photographers need to have photon counts in their images, is there?

Photography is the manipulation of light. The closer you get to working with the actual light the sensor collected, the more accurately you can manipulate it. Ideal would be development culminating in being able to change the color of the light in post with no difference to having put that colored gel on the light before pressing the shutter (for example). Remember, different colored light has different properties from penetrating slightly deeper into a material to bringing things into crisper focus (softness of blue light vs harshness of red light). Your suggested development would culminate in the data photographers edit having nothing to do with the original light, being all virtual data. It's easy to see that the development path leading to more true representation of the original photos will lead to more desirable results and more editing latitude.

 

[Chris R-UK]

... Unfortunately DNG is not widely supported by camera makers.

Why do you use the word "unfortunate" here?

Is it because you want all camera makers to use the same format, and if so, why?

Lots of reasons. The best one for me is that in the longer term a new format will replace "raw" and there will come a point when software will no longer support older raw files. Think of Betamax, 8 track tapes, 5.25" floppy disks, etc. If there is a single standard for raw files conversion programs are likely to be available for much longer into the future than if there are many hundreds or even thousands of different formats.

I really don't see why lossless JPEG would be worse than DNG. There is no reason photographers need to have photon counts in their images, is there?

"Lossless" JPEG format (like JPEG2000) in the sense that they use non-lossy compression algorithms as do TIFFs. They still contain less image data than a raw file because data is lost/changed in the conversion to an image file.

 

[CAcreeks]

Lots of reasons. The best one for me is that in the longer term a new format will replace "raw" and there will come a point when software will no longer support older raw files... If there is a single standard for raw files conversion programs are likely to be available for much longer into the future than if there are many hundreds or even thousands of different formats.

That makes sense, but at present DNG is just another Raw format and merely adds to our confusion. The point at which mainstream camera manufacturers might adopt DNG has passed, possibly 10 years ago.

"Lossless" JPEG format (like JPEG2000) in the sense that they use non-lossy compression algorithms as do TIFFs. They still contain less image data than a raw file because data is lost/changed in the conversion to an image file.

OK, this is similar to the photons argument made above. Maybe true. However it seems to me that if a lossless JPEG is infinitely editable, you can reach the same goal. So I believe the Raw cult is unnecessary in the long run. It was forced on photographers by lousy in-camera JPEG from the major vendors (less so Fuji and Olympus).

 

[Allan Olesen]

How is that relevant? It does not disprove that CR2 is compressed with lossless JPEG, since TIFF is a container format which can be used for several different compressed and non-compressed image formats.

Sites which write "RAW" in capital letters, as if it's an acronym, annoy me immensely.

Me too, but how is that relevant?

there is no 14-bit JFIF standard, therefore the 14-bit data cannot be stored as compressed, uncompressed, encoded, unencoded, encrypted or unencrypted JPG anything. Was that clear enough for you, or do you need it phrased differently?

Yes, it appears I need it phrased differently.

I'm saying 14-bit, because RAW images out of most cameras are 14-bit, but there are also 16-bit raw images, 24-bit, 32-bit, 48-bit and 64-bit raw images. There is no way to store any of those in an 8-bit container.

If lossless JPEG is only 8 bit, it seems strange that Adobe's Thomas Knoll used this reason for using lossless JPEG in the DNG standard:

On why lossless JPEG was preferred over ZIP compression, Knoll explained, "PNG uses ZIP compression, which does poorly on data deeper than 8 bits/channel, which most raw formats contain. I actually tried ZIP compression in prototype versions of DNG, but the compression ratio was much better using lossless JPEG."

Source: http://www.imaging-resource.com/IRNEWS/archive/v06/20041001.htm

 

[Ray Ritchie]

Thanks for the detailed response. Just to clarify my question and comments, it has to do with whether it is really sufficient to dismiss a format simply because it is an "image format." I don't want to debate whether raw is better (I shoot only raw myself these days, but have shot a lot of JPEG's in the past, so I appreciate the current differences), or whether this particular new JPEG format can "replace raw." But I do think it's quite possible that today's 8-bit JPEG implementations in cameras will eventually be replaced by some new format (maybe this one?) which is capable of higher quality. As the quality of such a future OOC JPEG improves, it seems likely to me that fewer and fewer people would bother to shoot in raw format. So whether an "image format" has the flexibility of a raw format or not (e. g., in terms of the potential for many different renderings of the same image), it seems possible that in terms of usage, raw could be "replaced," for better or worse. I'd think that it depends mostly on how much better quality can be achieved with that mythical future format - and I'm not at all clear on how you have so quickly determined that this particular new format is not good enough to be "the one."

Has anyone heard about a new version of JPEG which is a lossless format and could replace RAW?

RAW files are NOT image formats. They cannot be sensibly displayed as an image. They store sensor data, which has to be converted into a format ( like a JPEG ) which can be viewed normally. This process involves processing steps.

I hear this sort of characterization of raw a lot, but the importance of the point is lost on me. Perhaps you could elaborate on what constitutes an "image format"?

A RAW file contains photon counts. A JPEG, TIFF or other image format does not.

I can create an arbitrary number of images from a single RAW. Any one of those is a legitimate image of the scene which is defined by a combination of the original RAW data and parameters I add in processing from RAW to JPEG. These parameters control things like tone curve ( RAW data does not have a luminance curve that is a match to human vision and the media we design for that purpose.

I cannot display an image without adding some parameters to the RAW data to control that processing.

A JPEG or other image format already has those parameters "cooked in". The JPEG stores data that matches the display requirements needed to produce an image. The data in a JPEG is designed to be used by output devices. RAW data is not.

But how much of that is important to, say, 90% or even 99% of all digital camera users? I don't have any actual data, but I suspect that more than 90% of all digital photographers today use some form of JPEG straight from the camera. Surely that percentage will only increase if JPEG quality improves. Those of us who shoot raw are a tiny minority, even today.

Neither a JPEG file nor a raw file can be displayed directly, without the aid of some decoding software. The software for decoding a JPEG is actually pretty complex, since the encoding process uses several layers of different techniques, including segmenting the image into blocks, differential encoding, transformation to the frequency domain, Huffman encoding, etc.

You are confusing compression of data ( which is what JPEG does ) and the transformation processing required to convert photon counts to output device orientated display data.

Actually some RAW files use compression not dissimilar to JPEG encoding.

From the point of view of a computer engineer compression is seen as a separate thing from any other kinds of processing. The difference between the formats remains - an image format is "display ready" data ( compressed or not ) and a RAW file does NOT contain display ready data ( compressed or not ).

I'm just trying to understand what's really important in distinguishing "image formats" from raw formats. Is it the lossless property? The new format claims to be lossless. The fact that JPEG is tied to a tone curve and color space? One reason those two things matter is that today's JPEG's are only 8-bit, and changing the color space or tone curve in post-processing can degrade the image. But I would think that with a 12-bit JPEG, such post-processing degradation would be lessened.

In some ways, typical raw formats are more directly related to the original image, in that most of the bits in a raw format have a direct relationship to a known portion of the image as it was focussed on the sensor by the lens. In the case of JPEG, I don't think you can point to any particular bit or byte in the JPEG-encoded file which relates directly to the original image seen by the sensor.

Actually that's the point. The image data is processed data intended for consumption by output media. It does not require any relationship with the source data ( the RAW data ). It can be anything.

So since neither JPEG nor raw files can be directly displayed, and the JPEG is derived from the raw, and both require complex decoding software, why is one more of an "image format" than the other?

The data in a RAW file cannot be displayed with additional processing controlled by parameters defined outside the RAW file.

The data in an image format ( like JPEG ) can be displayed without reference to data outside the scope of the image file's own data.

JPEG is a format designed to store an image. You cannot recover a RAW file from a JPEG ( or any "cooked" image format ). This is because the processing that converts the sensor data in the RAW file make irreversible changes to the data.

There is a lossless JPEG format called JPEG2000. This is not normally used in photographic or media applications. It is used in some medical systems ( where any loss of data is unacceptable ). If JPEG2000 did not catch on ( and it has 16-bit capability, not 12 ) it's seems unlikely that this new format will.

I'm not sure how you can make that judgment without a detailed study of the new proposal.

I can. I've been involved in both IT and photography for a long, long time now.

You need to understand that the reason why the existing 8-bit 3-channel JPEG format has survived and will continue to survive as the primary format for processed image exchange is that it is a format that is used everywhere. It's good enough for the job it does and converting or replacing systems to use a new standard would be so expensive that it's prohibitive.

Standards persist because they work well enough and the cost of change is prohibitive for the marginal benefit.

That's why this new JPEG format won't set the world alight.

I was involved in digital communication standards in the ITU for about 10 years, including chairing a number of efforts, so I have some appreciation of the resistance of standards to change. I wasn't actively involved in JPEG, but did get to sit in on several of the meetings which led to that standard. It seems to me that it's inevitable that 8-bit JPEG's will eventually be replaced by something better, and I don't see much hope for standardization of raw formats; I think the camera manufacturers will see such standardization as putting limits on their future innovations which might otherwise give them market advantage.

Thanks again for amplifying your views for me.

--
Ray
My blog: http://www.rritchie.com/wordpress
My Flickr page: http://www.flickr.com/photos/rritchie/

 

[CAcreeks]

If lossless JPEG is only 8 bit, it seems strange that Adobe's Thomas Knoll used this reason for using lossless JPEG in the DNG standard:

On why lossless JPEG was preferred over ZIP compression, Knoll explained, "PNG uses ZIP compression, which does poorly on data deeper than 8 bits/channel, which most raw formats contain. I actually tried ZIP compression in prototype versions of DNG, but the compression ratio was much better using lossless JPEG."

From the JPEG FAQ:

For lossless JPEG, the standard permits any data precision between 2 and 16 bits per sample, but high-precision lossless JPEG is even less widely supported than high-precision lossy JPEG. The Stanford PVRG codec (see part 2, item 15) reportedly supports up to 16 bits/sample for lossless JPEG.

 

[darklamp]

... Unfortunately DNG is not widely supported by camera makers.

Why do you use the word "unfortunate" here?

Is it because you want all camera makers to use the same format, and if so, why?

Yes, I would like all makers to support DNG ( or some common format for RAW ).

The what is simple - do away with the need for software upgrades and a better assurance that your RAW files will be supported by future software.

I really don't see why lossless JPEG would be worse than DNG. There is no reason photographers need to have photon counts in their images, is there?

Yes, there is.

I've already explained this ( and many others have elsewhere ), so I'm reluctant to say it again. JPEGs are "cooked", RAW is "uncooked". You can make a lot more dishes from uncooked ingredients than you can from cooked meals.

RAW data is maximum flexibility for processing.

 

[BG454]

The raw data in Canon CR2 files are compressed with lossless JPEG. I have no idea why you think that lossless JPEG is 8 bit.
You can read a detailed description of what a .CR2 contains here:

http://lclevy.free.fr/cr2/#lossless

Ah yes, in which it clearly states (under section 2.1 Overview):

"The .CR2 file is based on the TIFF file format. This TIFF file has 4 Image File Directories (IFDs). "

How is that relevant? It does not disprove that CR2 is compressed with lossless JPEG, since TIFF is a container format which can be used for several different compressed and non-compressed image formats.

So the site you referenced clearly says .CR2 is based on TIFF, and yet you still maintain it's lossless JPEG.
The words "sorry, I was mistaken" clearly do not exist in your vocabulary.

Personally, I don't give a toss what format .CR2 is based on, as long as it continues to give me the results I need.

 

[GordonBGood]

The raw data in Canon CR2 files are compressed with lossless JPEG. I have no idea why you think that lossless JPEG is 8 bit.
You can read a detailed description of what a .CR2 contains here:

http://lclevy.free.fr/cr2/#lossless

Ah yes, in which it clearly states (under section 2.1 Overview):

"The .CR2 file is based on the TIFF file format. This TIFF file has 4 Image File Directories (IFDs). "

How is that relevant? It does not disprove that CR2 is compressed with lossless JPEG, since TIFF is a container format which can be used for several different compressed and non-compressed image formats.

So the site you referenced clearly says .CR2 is based on TIFF, and yet you still maintain it's lossless JPEG.
The words "sorry, I was mistaken" clearly do not exist in your vocabulary.

Personally, I don't give a toss what format .CR2 is based on, as long as it continues to give me the results I need.

why would Alan say he's sorry when he is correct: the Tiff format is a container format that can contain many kinds of image data including the usual (for the base TIFF specification) uncompressed data or data compressed both by lossy compression including zip type compression or loss-less compression such as JPEG-LS Huffman compression. The Canon CR2 file format uses the TIFF format to contain a proprietary loss-less compression somewhat similar to the JPEG-LS standard although not identical.

Regards, GordonBGood

 

[canonagain123]

The raw data in Canon CR2 files are compressed with lossless JPEG. I have no idea why you think that lossless JPEG is 8 bit.
You can read a detailed description of what a .CR2 contains here:

http://lclevy.free.fr/cr2/#lossless

Ah yes, in which it clearly states (under section 2.1 Overview):

"The .CR2 file is based on the TIFF file format. This TIFF file has 4 Image File Directories (IFDs). "

How is that relevant? It does not disprove that CR2 is compressed with lossless JPEG, since TIFF is a container format which can be used for several different compressed and non-compressed image formats.

So the site you referenced clearly says .CR2 is based on TIFF, and yet you still maintain it's lossless JPEG.
The words "sorry, I was mistaken" clearly do not exist in your vocabulary.

Personally, I don't give a toss what format .CR2 is based on, as long as it continues to give me the results I need.

why would Alan say he's sorry when he is correct: the Tiff format is a container format that can contain many kinds of image data including the usual (for the base TIFF specification) uncompressed data or data compressed both by lossy compression including zip type compression or loss-less compression such as JPEG-LS Huffman compression. The Canon CR2 file format uses the TIFF format to contain a proprietary loss-less compression somewhat similar to the JPEG-LS standard although not identical.

Regards, GordonBGood

The words "sorry, I was mistaken" clearly do not exist in your vocabulary. This is clearly true for the both of you. Is it JPEG or is it like JPEG? Like JPEG is not JPEG. Is it JPEG is a binary question, the answer is either "Yes, it's JPEG" or "No, it's not JPEG". By the way, compression of what? Just because the compression algorithm is similar, doesn't mean the data it compresses is!

Incredible how hard it is for some people to admit they were wrong and not try to wiggle their way out of things with semantics.

 

[GordonBGood]

The raw data in Canon CR2 files are compressed with lossless JPEG. I have no idea why you think that lossless JPEG is 8 bit.
You can read a detailed description of what a .CR2 contains here:

http://lclevy.free.fr/cr2/#lossless

Ah yes, in which it clearly states (under section 2.1 Overview):

"The .CR2 file is based on the TIFF file format. This TIFF file has 4 Image File Directories (IFDs). "

How is that relevant? It does not disprove that CR2 is compressed with lossless JPEG, since TIFF is a container format which can be used for several different compressed and non-compressed image formats.

So the site you referenced clearly says .CR2 is based on TIFF, and yet you still maintain it's lossless JPEG.
The words "sorry, I was mistaken" clearly do not exist in your vocabulary.

Personally, I don't give a toss what format .CR2 is based on, as long as it continues to give me the results I need.

why would Alan say he's sorry when he is correct: the Tiff format is a container format that can contain many kinds of image data including the usual (for the base TIFF specification) uncompressed data or data compressed both by lossy compression including zip type compression or loss-less compression such as JPEG-LS Huffman compression. The Canon CR2 file format uses the TIFF format to contain a proprietary loss-less compression somewhat similar to the JPEG-LS standard although not identical.

Regards, GordonBGood

The words "sorry, I was mistaken" clearly do not exist in your vocabulary. This is clearly true for the both of you. Is it JPEG or is it like JPEG? Like JPEG is not JPEG. Is it JPEG is a binary question, the answer is either "Yes, it's JPEG" or "No, it's not JPEG". By the way, compression of what? Just because the compression algorithm is similar, doesn't mean the data it compresses is!

Incredible how hard it is for some people to admit they were wrong and not try to wiggle their way out of things with semantics.

Your mistake arises from assuming that the JPEG standard only includes the lossy compression of images as described by this wikipedia article, but you'll note in reading that article that the JPEG standard (T.81 Part 1 - 9/92) which was made into ISO/IEC standard 10918 in 1994) includes more than just that base capability. The ITU.T T.81 document describes both the use of the standard for the usual lossy compression and decompression codecs as well as in Annex H a specification for using a Loss Less Compression using Huffman encoding for bit depths from two to sixteen bits. Thus, the JPEG standard describes a container format that can contain images encoded with various schemes including the usual one but also a loss less mode not commonly supported by base JPEG codecs. A JPEG format is just a container format just as is a TIFF format, each of which can include images encoded in the other as part of their format.

As to what data is encoded as to channels, that to is specified in the above JPEG standard document.

The Adobe raw DNG format expressly uses exactly the JPEG Loss Less option for compression inside a TIFF container as is part of its specification whereas other proprietary raw formats use slight variations of the same basic JPEG Loss Less techniques, also inside TIFF containers for the most part. THE DNG standard adds meta data "tags" to the TIFF standard so that the DNG file format must contain enough information to allow a raw converter application to be able to fully decode the raw data to a displayable image without knowing anything more about the camera producing the raw data.

So in answer to your binary questions, no the Canon CR2 and Nikon NEF raw formats do not include JPEG raw data inside their TIFF envelopes because they do not adhere exactly to the JPEG standard including Annex H (although there are some close similarities), and the loss-less compressed raw data section of DNG is actually a true embedded JPEG image as per Annex H, just as embedded thumbnails and previews also adhere to that standard as they can be encoded as base loss eight-bit JPEG images (with some overlap from the TIFF standard in describing this).

The reason that base JPEG decoders cannot view such images is because they are base and because these images are encoded as un-demosiaced raw data which needs to be raw converted to produce something displayable on an RGB display. That is why as standard such as DNG needs to exist in order to provide enough information to allow this raw conversion of the raw data without knowing any other details of the camera producing the image.

You are ignoring that both JPEG and TIFF (especially TIFF) are container formats intended to have the capability to contain other formats, where TIFF can contain any of the standard JPEG formats, and JPEG can contain many variations including some of the forms of TIFF type formats in particular sections. For instance, JPEG thumbnails are often encoded as an embedded uncompressed TIFF format complete with TIFF headers.

You seem to be fixed in thinking that if a file can't be opened and displayed by the common base JPEG or TIFF decoder on your computer it is then not JPEG or TIFF formatted, respectively; however, that is not the case as those are just base decoders.

I suggest you read and fully digest the above linked or referred standards documents before you comment further.

 

[canonagain123]

The raw data in Canon CR2 files are compressed with lossless JPEG. I have no idea why you think that lossless JPEG is 8 bit.
You can read a detailed description of what a .CR2 contains here:

http://lclevy.free.fr/cr2/#lossless

Ah yes, in which it clearly states (under section 2.1 Overview):

"The .CR2 file is based on the TIFF file format. This TIFF file has 4 Image File Directories (IFDs). "

How is that relevant? It does not disprove that CR2 is compressed with lossless JPEG, since TIFF is a container format which can be used for several different compressed and non-compressed image formats.

So the site you referenced clearly says .CR2 is based on TIFF, and yet you still maintain it's lossless JPEG.
The words "sorry, I was mistaken" clearly do not exist in your vocabulary.

Personally, I don't give a toss what format .CR2 is based on, as long as it continues to give me the results I need.

why would Alan say he's sorry when he is correct: the Tiff format is a container format that can contain many kinds of image data including the usual (for the base TIFF specification) uncompressed data or data compressed both by lossy compression including zip type compression or loss-less compression such as JPEG-LS Huffman compression. The Canon CR2 file format uses the TIFF format to contain a proprietary loss-less compression somewhat similar to the JPEG-LS standard although not identical.

Regards, GordonBGood

The words "sorry, I was mistaken" clearly do not exist in your vocabulary. This is clearly true for the both of you. Is it JPEG or is it like JPEG? Like JPEG is not JPEG. Is it JPEG is a binary question, the answer is either "Yes, it's JPEG" or "No, it's not JPEG". By the way, compression of what? Just because the compression algorithm is similar, doesn't mean the data it compresses is!

Incredible how hard it is for some people to admit they were wrong and not try to wiggle their way out of things with semantics.

Your mistake arises from assuming that the JPEG standard only includes the lossy compression of images as described by this wikipedia article, but you'll note in reading that article that the JPEG standard (T.81 Part 1 - 9/92) which was made into ISO/IEC standard 10918 in 1994) includes more than just that base capability. The ITU.T T.81 document describes both the use of the standard for the usual lossy compression and decompression codecs as well as in Annex H a specification for using a Loss Less Compression using Huffman encoding for bit depths from two to sixteen bits. Thus, the JPEG standard describes a container format that can contain images encoded with various schemes including the usual one but also a loss less mode not commonly supported by base JPEG codecs. A JPEG format is just a container format just as is a TIFF format, each of which can include images encoded in the other as part of their format.

As to what data is encoded as to channels, that to is specified in the above JPEG standard document.

The Adobe raw DNG format expressly uses exactly the JPEG Loss Less option for compression inside a TIFF container as is part of its specification whereas other proprietary raw formats use slight variations of the same basic JPEG Loss Less techniques, also inside TIFF containers for the most part. THE DNG standard adds meta data "tags" to the TIFF standard so that the DNG file format must contain enough information to allow a raw converter application to be able to fully decode the raw data to a displayable image without knowing anything more about the camera producing the raw data.

So in answer to your binary questions, no the Canon CR2 and Nikon NEF raw formats do not include JPEG raw data inside their TIFF envelopes because they do not adhere exactly to the JPEG standard including Annex H (although there are some close similarities), and the loss-less compressed raw data section of DNG is actually a true embedded JPEG image as per Annex H, just as embedded thumbnails and previews also adhere to that standard as they can be encoded as base loss eight-bit JPEG images (with some overlap from the TIFF standard in describing this).

The reason that base JPEG decoders cannot view such images is because they are base and because these images are encoded as un-demosiaced raw data which needs to be raw converted to produce something displayable on an RGB display. That is why as standard such as DNG needs to exist in order to provide enough information to allow this raw conversion of the raw data without knowing any other details of the camera producing the image.

You are ignoring that both JPEG and TIFF (especially TIFF) are container formats intended to have the capability to contain other formats, where TIFF can contain any of the standard JPEG formats, and JPEG can contain many variations including some of the forms of TIFF type formats in particular sections. For instance, JPEG thumbnails are often encoded as an embedded uncompressed TIFF format complete with TIFF headers.

You seem to be fixed in thinking that if a file can't be opened and displayed by the common base JPEG or TIFF decoder on your computer it is then not JPEG or TIFF formatted, respectively; however, that is not the case as those are just base decoders.

I suggest you read and fully digest the above linked or referred standards documents before you comment further.

Took awfully many words to say "You're right."

JPEG supports true lossless compression, but it is used so rarely that JPEG is commonly thought of as strictly a lossy format.A lossless JPEG is identified by the presence of an SOF3, SOF7, SOF11, or SOF15 segment. The original lossless JPEG (sometimes called lossless JPEG-1) refers to the original JPEG format when used with lossless compression, instead of the usual lossy compression. It is a standard type of JPEG file, defined in the original JPEG standard (ITU-T Rec. T.81). Few applications support it, though it has found some use in the medical industry, such as in DICOM files. Note that this format is distinct from JPEG-LS.A lossless JPEG image may have any bit depth from 2 to 16 bits per sample. The compression scheme uses Huffman coding or arithmetic coding.

Any encoding can be used to encode any data. You can MIME encode a RAW image or you can QR encode it. As long as you have the correct decoder you can decode it. The question that ability doesn't answer is how practically useful it is to encode a RAW image with Huffman, MIME, QR or any encoding of your heart's desire. If all you want to say is "it's possible", I heartily agree—any encoding can be used to encode any data.

 

[newmikey]

The TIFF image format we tend to use as a way to store and print images as opposed to the TIFF/EP format used inside many manufacturers' raw files?

Not an expert but just pointing out the obvious.

"Tag Image File Format / Electronic Photography (TIFF/EP) is a digital image file format standard – ISO 12234-2, titled "Electronic still-picture imaging – Removable memory – Part 2: TIFF/EP image data format". This is different from the Tagged Image File Format, which is a standard administered by Adobe currently called "TIFF, Revision 6.0 Final – June 3, 1992"."

TIFF, the image format can use 4 different types of compression:

• CCITT T.4 bi-level encoding
• CCITT T.6 bi-level encoding
• LZW Compression scheme
• JPEG-based compression (TIFF compression scheme 7) uses the DCT (Discrete Cosine Transform) introduced in 1974 by N. Ahmed, T.Natarajan and K.R. Rao; see Reference 1 in Discrete cosine transform. For more details see Adobe document.

Whereas TIFF/EP can use: "Most raw formats implement lossless data compression to reduce the size of the files without affecting image quality. But some others use lossy data compression where quantization and filtering is performed on the image data. Several recent Nikon cameras let photographers choose between no compression, lossless compression or lossy compression for their raw images."

Confused? So am I but sometimes we can all use the same acronym (TIFF) that turns out to have different meanings depending on where it is used.

As to JPEG? It can be 8-bit or 12-bit, lossy or lossless:

"The compression method is usually lossy, meaning that some original image information is lost and cannot be restored, possibly affecting image quality. There is an optional lossless mode defined in the JPEG standard. However, this mode is not widely supported in products.

There are also many medical imaging and traffic systems that create and process 12-bit JPEG images, normally grayscale images. The 12-bit JPEG format has been part of the JPEG specification for some time, but this format is not as widely supported."