Need Elaboration

[andalus]

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I understand that DNG's out of my M9 are "digital negatives" and can be manipulated in CS5 or LR3 any way one likes, and then re-manipulated again if one so chooses, non destructively I presume.

 

But say I "save as" a DNG file as a TIF. (But keep the original DNG, too.) Is the TIF file also, more or less, similarly open to manipulation and further refinement the same way a DNG is -- I guess "non destructively"?

 

I have a bunch of TIF files that were created from scanned slides before I got the M9. Can they be turned back into DNG files or, if not, can they be manipulated at will in CS5 without degradation?

 

A better (quick) understanding of this would be greatly appreciated. I am thinking of getting an Epson 2880 and printing, and so these questions occur, as well as what the best file is to print FROM -- DNG, TIF or JPEG? Or does it matter?

 

Obviously I don't know much about all of this yet. Any elaboration much appreciated.

[ho_co]

TIFFs can't be converted to DNGs.

 

As long as you save the original TIFF and don't overwrite it, you can make any changes you want and save them as TIFFs, PSDs, etc, and still have the original file to go back to later. But that isn't a non-destructive process. Any time you modify data in a file, you lose some data that you can't get back.

 

The reason Lightroom is non-destructive to the DNG is that LR saves the instructions as to which corrections to apply, rather than the corrections themselves. Writing a TIFF or PSD or JPG is like making a print: The changes are final, and although you can reopen the TIFF and make changes, you're working only with the data still available in the final file.

 

(That's a little oversimplified. If you make changes in Photoshop by using layers, and then save all the layers in a PSD, you can later go back and modify the layers to get a different effect: Used that way, Photoshop becomes non-destructive. Example: Using a "Levels" Adjustment Layer to adjust tonality is non-destructive, while "Image > Adjustments > Levels" applies the change directly to the data. The latter is destructive and leaves the data permanently modified.)

[delander †]

Tifs are not like dng RAW files, but if you have 16bit tifs they can take quite a lot of manipulation without showing unwanted effects. As Howard says if you use adjustment layers in Photoshop then it is only when you flatten the image that the adjustments become permanent.

 

My personal workflow is to do basic adjustments in the RAW converter and then export the image as 16bit tif and do the rest in Photoshop. But I have been using Photoshop for 15 years so I tend to stick with what I know.

 

Jeff

[andalus]

thank youi both above. this is helpful!

[andalus]

Let's say I have a TIFF file and a JPEG file. Is there any qualitative difference printing one over the other, or do they come out the same in the print on paper?

[chuckw]

Assuming you start with a RAW file and convert that to a TIFF in the process of editing - I would always print from the TIFF file rather than a JPEG. Why print from a file (JPEG) where a lot of information has been thrown away? That said, a lot of very good prints certainly have been made from JPEGS but I would rather error on the side of caution and print from a file that contains the most information.

[perb]

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TIFFs can't be converted to DNGs.

 

Perhaps Lightroom/Photoshop can't, but there may be other s/w that can. In fact, when Adobe created DNG they used TIFF as a template, so the innards are in fact very similar. See Digital Negative (file format) - Wikipedia, the free encyclopedia for details. Of course, the reason Adobe didn't just use TIFF as is was that it didn't have all the mechanisms that you want in a raw format, so I suppose you could say that "DNG is more raw than TIFF"

 

I use Capture One, and it can open a TIFF and can save as DNG, but I haven't had a reason to try, so I don't know how it works out

 

Also, as explained in Adobe DNG Profiles and Profile Editor you can use adobe s/w (the latest free DNG converter, Lightroom or Camera Raw) to convert most raw formats to DNG. See also DNG, digital negative | Adobe

 

The reason Lightroom is non-destructive to the DNG is that LR saves the instructions as to which corrections to apply, rather than the corrections themselves.

 

Again, I haven't tried in C1, but there is no reason the same procedure couldn't be applied to a TIFF. It is up to the maker of the s/w to decide.

 

Regards

Per

[Shootist]

I understand that DNG's out of my M9 are "digital negatives" and can be manipulated in CS5 or LR3 any way one likes, and then re-manipulated again if one so chooses, non destructively I presume.

 

But say I "save as" a DNG file as a TIF. (But keep the original DNG, too.) Is the TIF file also, more or less, similarly open to manipulation and further refinement the same way a DNG is -- I guess "non destructively"?

 

I have a bunch of TIF files that were created from scanned slides before I got the M9. Can they be turned back into DNG files or, if not, can they be manipulated at will in CS5 without degradation?

 

A better (quick) understanding of this would be greatly appreciated. I am thinking of getting an Epson 2880 and printing, and so these questions occur, as well as what the best file is to print FROM -- DNG, TIF or JPEG? Or does it matter?

 

Obviously I don't know much about all of this yet. Any elaboration much appreciated.

 

A DNG file is always a Digital Negative. It will always need to be opened in a RAW converter of some type before you can do anything else with it. A TIFF or PSD is the RAW file converted to it full size with a color space and bit depth assigned. TIFF or PSD files are much larger then a RAW file. Most RAW files from a 10MP camera are somewhere in the range of 8 to 12 MB. That same file run through a RAW processor and saved as a TIFF or PSD is 58 to 65MB before you do any adjustments and if you add layers it can go to 150+MB. All adjustments made to a TIFF or PSD file are destructive adjustment, they change the file. The only way for it to not change the original TIFF or PSD is to save it under a different file name.

 

JPG's are only good for sending the image to someone that does not have photo editing software or displaying that image on the web.

[ho_co]

Per, thanks for pointing out my errors.

 

As I said, I oversimplified to avoid complicating the issue more than necessary.

 

C1 used to be able to create an uncorrected DNG from the D-Lux 4's RWLs, but Leica asked Phase One to remove that facility. And as you said, although you can read a TIFF and create a DNG from it, you (and I) have never discovered a reason to do so.

 

So in practical terms, to my mind, a DNG is a beginning point and a TIFF is an end point. You can load a TIFF and keep working on it, but you can never restore the information you discarded when you first wrote the TIFF; so in that sense, you can't turn it back into the DNG from which it originated.

 

 

 

... Again, I haven't tried in C1, but there is no reason the same procedure couldn't be applied to a TIFF....

I'm not very familiar with Lightroom, and I am hardly know Capture One at all, so I don't follow. Therefore, let me ask: As I understand it, Versions 3 and 4 of C1 were bit-level processors like early (and at its base, also current) Photoshop. Are you saying that in version 5, C1 offers the option of saving instructions within the DNG, as Lightroom does? Or are you saying that C1 allows writing TIFFs which include adjustment layers atop the basic starting image, as Photoshop does? Or are you saying there is some other way to write TIFFs non-destructively in Capture One?

 

Thanks!

[ho_co]

Let's say I have a TIFF file and a JPEG file. Is there any qualitative difference printing one over the other, or do they come out the same in the print on paper?

 

Andalus, I think Chuck's response above amounts to a very polite, " Horrors! Why would you ask such a thing?"

 

I think the direct answer to your question is "No, as far as what the printer sees, there will be no difference between the results from a good TIFF and a good JPG, all else being equal." But as Chuck implies, that may be missing the point.

 

As I understand it, JPG was invented by HP and Microsoft as a quick-and-dirty compression scheme to reduce file size for faster transfer.

 

JPG is lossy. That is, data are irretrievably lost when you write a JPG. That means that if you load a JPG, make no changes, and then save it again, the second file will no longer have as much information as the original had. Load and save again, and the same thing will happen. And so on ad infinitum.

 

What that means is that JPG is only useful as a final product. (Yes, I know, you can load it and make changes and save it again, but if you intend to do that, you shouldn't be using JPG.)

 

 

One other word usage point: DNG is simply another RAW format, invented by Adobe in the hopes that it would become a universal standard and reduce the proliferation of various incompatible RAW formats. "DNG" is a shortened form of "Digital NeGative."

 

In that sense, all RAW formats are "digital negatives," because they contain as much information as the camera manufacturer is going to give you.

 

 

Those two points are well-known, but may be helpful to someone just starting to try to make sense of the various formats.

 

Hope that helps just a bit.

[250swb]

Andalus the way I do it is to work on the dng in the RAW converter until its as good as I can get it. As you say, this is non-destructive. Then 'export' to CS5 (press 'Open Image') as a 16bit TIFF and save this. From then on this is the image I work with, maybe doing some dodging or burning, local contrast adjustments, convert to B&W etc. When done I save this as another TIFF. From then on this is the image I use for printing, resizing, converting to JPEG etc. So the TIFF file is the finished image, and the one that all subsequent lossey versions are converted from.

 

Steve

[perb]

Are you saying that in version 5, C1 offers the option of saving instructions within the DNG, as Lightroom does? Or are you saying that C1 allows writing TIFFs which include adjustment layers atop the basic starting image, as Photoshop does? Or are you saying there is some other way to write TIFFs non-destructively in Capture One?

 

The way I understand it is that when you open a raw/DNG in C1 and apply adjustments to it, the original raw/DNG stays untouched (check the file time stamp). C1 will create a subdirectory named "CaptureOne" next to your raw/DNG where it will store both a high quality thumbnail and also a file with all the modifications (think of it as storing a list of all your mouse clicks). If you close C1 and then later open it again, C1 will load the original raw/DNG, read the list of modifications and then apply the modifications to the loaded raw/DNG such that you will see it on the screen as you previously left it.

 

At this point you could, if you wanted, decide that your modifications are not good and tell C1 to reset, leaving you with the original default rendering.

 

While the above is what C1, Lightroom and many other raw converters do, there is, in principle, nothing preventing us from applying the same scheme on any kind of file, be it TIFF, JPG or whatever. I say "in principle" because I know no s/w that does this, because, as you pointed out, in practice this scheme is only useful for raw.

 

It is worth mentioning here that the makers of C1 have invented a file format called "eip", and just like Adobe are promoting their DNG format, PhaseOne are trying to turn eip-files into an industry standard.

 

An eip-file is a container for a raw file and the file containing your modifications to said raw file, all in one piece. This means that, staying with C1, I can load one of my DNG's into C1, make my adjustments, package as eip, and send the eip file to you. When you recieve my eip-file you can open it in C1 and have exactly what I have, with full detail and no loss. You can then decide to make further adjustments, or you could decide that my modifications are crap and restore the original raw, or whatever

 

Note that caching the thumbnail will make C1 open faster next time. If you also make this a favourite, C1 will be even faster.

 

Regards

Per

[ho_co]

Thanks, Per. It's a lot clearer now. And of course, Capture One has just introduced a new version with even more stuff I don't understand.

 

 

No, I hadn't heard about eip. Sounds like a good idea, but may turn out to be just another non-standard 'standard.' The way you describe it, it sounds as if it'll work more or less just like a Lightroom DNG. I guess they can't pack C1 instructions in the DNG since LR already does that with its own instructions.

 

Still, if they get going on Expressions Media and Capture One, they'll have a heck of a product! Just a question of whether they can make it stick.

 

 

Hmm. What does all that mean for the universality of the DNG? If I make adjustments in LR and send you a copy of the DNG, I think you can read the adjustments in LR, but only in LR. Or am I wrong about that?

[hoppyman]

Howard that opens some more very interesting discussion areas. I just checked, saving a cropped and adjusted DNG as a new DNG with Camera Raw 5.4 and later compatibility. The new copy contains all of the (reversible) edit instructions when opened in LR of course and also in ACR. Opening the edited copy in C1 4.8.3 the thumbnail shows the edits but then the file shows the original (but with very differnt colour too). That makes sense if you think it through. The original information is always untouched and different software will write instructions differently.

 

HOWEVER, if you use the option in Lightroom to save the metadata to file, the edits are applied to the copy opened in C1 4.8.3. Note though that you cannot un-crop for example, back to the original if you do that. This starts to get into a develop history vs. develop settings discussion. Maybe too much for this thread

 

Remember that even entirely within Lightroom a DNG edited on one machine requires that the file be exported in a CATALOG to the other machine for all of the edit instructions, keywords, flags ratings etc to travel with it. The sidecar save option thingies don't apply to DNGs either.

 

........Hmm. What does all that mean for the universality of the DNG? If I make adjustments in LR and send you a copy of the DNG, I think you can read the adjustments in LR, but only in LR. Or am I wrong about that?

[ho_co]

... Remember that even entirely within Lightroom a DNG edited on one machine requires that the file be exported in a CATALOG to the other machine for all of the edit instructions, keywords, flags ratings etc to travel with it. The sidecar save option thingies don't apply to DNGs either.

 

Thanks, Geoff, for doing the experiments. I'm not comfortable enough with either C1 or LR to have done so.

 

Looks to me as if Adobe's development of the 'universal' DNG really does seem to move toward making it 'just another RAW.' And that's because of Adobe's handling of the DNG in its own software, making an exception to the rule of .xmp sidecar files.

 

But as you say, the photographer can get off the bus anywhere along the way.

[hoppyman]

Oh no, Howard, that rather misses the point all together!

 

Not to worry, in the end this discussion belongs in a more specialised forum. I'll leave it at that

[ho_co]

Oops. Now I'm totally lost, Geoff. --But then, I guess you'd already noticed that.

 

I'll go quietly.

[sandymc]

On the issue of the DNGs versus XMPs, the theory, and the original intent, was that XMPs are used for non-editable formats (e.g., NEFs, CR2s, etc). However, for editable formats, such as DNGs, the entire contents of the XMP can just be embedded into the DNG.

 

So, the in theory, a DNG that has been edited in Lightroom has the same information as a NEF plus the NEF's associated XMP file.

 

The practical problem, and the reason why there is so much confusion around this issue, is that in practice LR and Photoshop don't quite work that way. They mostly work that way, but under the right circumstances, for example, LR will create a XMP file for a DNG. So you can't ever quite be 100% confident where the metadata is.

 

Sandy

[Shootist]

On the issue of the DNGs versus XMPs, the theory, and the original intent, was that XMPs are used for non-editable formats (e.g., NEFs, CR2s, etc). However, for editable formats, such as DNGs, the entire contents of the XMP can just be embedded into the DNG.

 

So, the in theory, a DNG that has been edited in Lightroom has the same information as a NEF plus the NEF's associated XMP file.

 

The practical problem, and the reason why there is so much confusion around this issue, is that in practice LR and Photoshop don't quite work that way. They mostly work that way, but under the right circumstances, for example, LR will create a XMP file for a DNG. So you can't ever quite be 100% confident where the metadata is.

 

Sandy

 

Really Sandy? I have never noticed and XMP files being created when editing DNG files. But then I don't use LR much for editing. I use ACR/PS. Is it that setting in LR, something like create XMP for RAW edits (something like that) option?

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[sandymc]

Really Sandy? I have never noticed and XMP files being created when editing DNG files. But then I don't use LR much for editing. I use ACR/PS. Is it that setting in LR, something like create XMP for RAW edits (something like that) option?

 

Really.

 

Those settings effect it, but so does your file system, and probably a bunch of things as well. So, e.g., the conditions under which you get an XMP file are different depending on whether you're running XP or Win 7

 

Regards,

 

Sandy