Saving DxO Rendering Either as Tiff or DNG

[JimAscher]

I have recently acquired DxO as it seems to be usefully improving my RAW captures from my Panasonic Micro 4/3's camera, which has a reduced sized sensor from APS.  In the DxO process, I can save as either tiff or dng.  (Also jpeg, which I'm not interested in.)  As I then proceed to process the DxO rendered image in black-and-white with Silver Efex Pro 2, is there any advantage (or disadvantage) to a choice between a DxO conversion to tiff or dng?   What this query probably reveals is my basic ignorance as to which format -- tiff or dng -- retains the most useful information.   

[fdisilvestro]

If you intend to process all your images in B&W with Silver Efex Pro 2 then probably the best option is to save them as tiff.

If you use dng, you will have to convert the images to tiff either with ACR or LR before opening them in Silver Efex Pro.


Differences between DXO's tiff and dng:

Tiffs are 8 or 16 bits, color space sRGB or ADOBE RGB

DNGs  are "linear dng" which means that demosaicing and interpolation have been performed, but no color space encoding, gamma or white balance have been applied. Because of this, you can retain all the color information and work in the ProphotoRGB color space in LR or ACR.

The purpose for a DXO dng is to continue editing in ACR or LR, since they are basically the only applications that can handle that format (Aperture does not handle linear dngs).

When LR did not have optical corrections, this workflow made sense, nowadays less so.

Regards

[JimAscher]

If you intend to process all your images in B&W with Silver Efex Pro 2 then probably the best option is to save them as tiff.

If you use dng, you will have to convert the images to tiff either with ACR or LR before opening them in Silver Efex Pro.


Differences between DXO's tiff and dng:

Tiffs are 8 or 16 bits, color space sRGB or ADOBE RGB

DNGs  are "linear dng" which means that demosaicing and interpolation have been performed, but no color space encoding, gamma or white balance have been applied. Because of this, you can retain all the color information and work in the ProphotoRGB color space in LR or ACR.

The purpose for a DXO dng is to continue editing in ACR or LR, since they are basically the only applications that can handle that format (Aperture does not handle linear dngs).

When LR did not have optical corrections, this workflow made sense, nowadays less so.

Regards

Francisco:  As part of my initial experimentation after acquisition of DxO, I converted a previous raw capture from my Lightroom directory using both the DxO tiff and dng conversion options.   I saved both of these back into my Lightroom directory which contained the initial raw capture, and then was able to process both -- the DxO-converted tiff and dng -- with my Silver Efex Pro 2 plug-in to Lightroom.  SEP handled both the tiff and dng seemingly equally well.   Are there any lessons to be learned from this "experiment," beyond the apparent fact that for SEP use, it doesn't seem to matter whether I save the DxO conversion as either tiff or dng?  Many thanks for you clarification of these matters for me.  Regards, Jim

[digitaldog]

Pretty sure that after DXO processes the data, the DNG isn’t truly raw any longer, it is simply a rendered image within the DNG container so it would not be much different than a TIFF in terms of the control over raw data. As FranciscoDisilvestro points out, there is a difference in bit depth and color space which is somewhat useful, but don’t get the impression that DXO DNG is the same as a DNG converted from a raw and used within say ACR or Lightroom. And Silver Efex can’t handle raw data anyway, you’ll have to render the data into RGB pixels for it to do anything anyway. Going out to B&W, probably not much difference if the data is Adobe RGB or ProPhoto but I’d sure prefer the higher bit depth.

[JimAscher]

Pretty sure that after DXO processes the data, the DNG isn’t truly raw any longer, it is simply a rendered image within the DNG container so it would not be much different than a TIFF in terms of the control over raw data. As FranciscoDisilvestro points out, there is a difference in bit depth and color space which is somewhat useful, but don’t get the impression that DXO DNG is the same as a DNG converted from a raw and used within say ACR or Lightroom. And Silver Efex can’t handle raw data anyway, you’ll have to render the data into RGB pixels for it to do anything anyway. Going out to B&W, probably not much difference if the data is Adobe RGB or ProPhoto but I’d sure prefer the higher bit depth.

Developing a new work flow incorporating DxO is now the issue for me.  My former work flow had me downloading my raw images from my camera card to Lightroom (processing additionally in Photoshop for example if I wanted panoramas), then bringing up Silver Efex Pro in Lightroom for final processing, after perhaps some minor processing (cropping) in LR, then ending up in Lightroom for printing with QTR.

With DxO, I now have the option, as I understand it, of downloading my raw images to DxO directly from the camera card, converting either to tiff or dng (or both), then sending the image(s) to Lightroom and proceeding with SEP as before.  Or, downloading the raw images from the camera card to Lightroom (as previously), then moving selected raw images from the Lightroom directory to DxO, for processing there and return to Lightroom for SEP processing.  While, as I further understand it, a choice between DxO processing to tiff or dng shouldn't make much of a difference as far as SEP processing is concerned. 

Is any of this unnecessarily confusing?  Any further advice would be much appreciated.  Jim

[digitaldog]

With DxO, I now have the option, as I understand it, of downloading my raw images to DxO directly from the camera card, converting either to tiff or dng (or both), then sending the image(s) to Lightroom and proceeding with SEP as before. 

But the data isn't thes same as downloading into LR and processing. The DXO data is processed (a lot) compared to the DNG or raw data you hand off to LR without going first to DXO. You can go either route but be aware of the differences. A "linear dng" undergoing demosaicing and interpolation is not the same as the original raw or DNG as Francisco points out.

[JimAscher]

But the data isn't thes same as downloading into LR and processing. The DXO data is processed (a lot) compared to the DNG or raw data you hand off to LR without going first to DXO. You can go either route but be aware of the differences. A "linear dng" undergoing demosaicing and interpolation is not the same as the original raw or DNG as Francisco points out.

As I cannot go directly from DxO to SEP (as SEP is a plug-in for LR and PS) I have to eventually end up with the DxO processed image in LR or PS for work in SEP.  So, I believe what you're advising me though is to start with DxO in any case.  But I'm still, I regret, undecided whether I should convert the DxO image to tiff or dng for this sequence.  I suspect that the dng option is to be slightly preferred.  Again, many thanks, Jim 

[digitaldog]

As I cannot go directly from DxO to SEP (as SEP is a plug-in for LR and PS) I have to eventually end up with the DxO processed image in LR or PS for work in SEP.  So, I believe what you're advising me though is to start with DxO in any case.  But I'm still, I regret, undecided whether I should convert the DxO image to tiff or dng for this sequence.  I suspect that the dng option is to be slightly preferred.  

I don’t use DXO. I do use LR a lot. I’d never go into LR with anything less than raw data which DXO doesn’t provide anyway. And SEP can’t use. Each raw processor is proprietary in how it handles the processing. When you use SEP, which has no ability to deal with the raw processing engine in LR, LR just spits out a TIFF. There is zero difference if you apply SEP in LR or Photoshop! If you didn’t own Photoshop but did own LR, well there’s a reason to use it there, but the bottom line is, as soon as you move into SEP, your raw processing is over and done. That is fine if you are sure you are done, just like when you tell LR to Edit in Photoshop or Export to a TIFF or PSD, you’ve finished using the raw processing engine in LR. So this is all about workflow.

[fdisilvestro]

Francisco:  As part of my initial experimentation after acquisition of DxO, I converted a previous raw capture from my Lightroom directory using both the DxO tiff and dng conversion options.   I saved both of these back into my Lightroom directory which contained the initial raw capture, and then was able to process both -- the DxO-converted tiff and dng -- with my Silver Efex Pro 2 plug-in to Lightroom.  SEP handled both the tiff and dng seemingly equally well.   Are there any lessons to be learned from this "experiment," beyond the apparent fact that for SEP use, it doesn't seem to matter whether I save the DxO conversion as either tiff or dng?  Many thanks for you clarification of these matters for me.  Regards, Jim

What happes is that LR converts the dng to tiff before sending it to SEP. I would basically decide on which choice of format depending on wheter further edits on the image will be performed in LR before going to SEP.

Advantages of using DXO dng if you edit the image in LR:
- You can apply a DNG profile. You can even produce a custom DNG profile from a DXO dng file with the xrite tool
- White balance performed to linear data
- More highlight recovery capability*

If you perform all preliminary edits in DXO and would use SEP from DXO if you had the chance, then just work in tiff.

I did some tests in DXO, especially with the dng options in this thread

* There is a interesting issue about what happens if you have clipped raw values, which I explain in the mentioned thread. Basically if your original raw file has any clipped highlights, it is recommended to white balance the image in DXO even if you output to dng.

[JimAscher]

What happes is that LR converts the dng to tiff before sending it to SEP. I would basically decide on which choice of format depending on wheter further edits on the image will be performed in LR before going to SEP.

Advantages of using DXO dng if you edit the image in LR:
- You can apply a DNG profile. You can even produce a custom DNG profile from a DXO dng file with the xrite tool
- White balance performed to linear data
- More highlight recovery capability*

If you perform all preliminary edits in DXO and would use SEP from DXO if you had the chance, then just work in tiff.

I did some tests in DXO, especially with the dng options in this thread

* There is a interesting issue about what happens if you have clipped raw values, which I explain in the mentioned thread. Basically if your original raw file has any clipped highlights, it is recommended to white balance the image in DXO even if you output to dng.

Thanks again. All that I've read here so far is steering me towards an initial raw conversion with DxO as dng before sending it off to further editing in Lightroom and SEP.   

[JimAscher]

Thanks again. All that I've read here so far is steering me towards an initial raw conversion with DxO as dng before sending it off to further editing in Lightroom and SEP.   

For what it's worth, after a day's further testing, I seem to end up with slightly better images from a DxO conversion to tiff than to dng.  (Why, I don't know.)  And I also seem to be able to process such tiff conversions fine for my purposes in LR and PS.  While there is a difference in file size between the two (the tiff being larger), when I create panoramas with PS Photomerge utilizing either the DxO tiff or dng files, the resulting panoramas end up with exactly the same file size whether starting with tiff or dng.  My previous panoramas starting with the same images without the DxO processing, ended up with larger-file-sized panoramas.  So, for now I'll stick with the DxO conversion to tiff.

[fdisilvestro]

For what it's worth, after a day's further testing, I seem to end up with slightly better images from a DxO conversion to tiff than to dng. 

Is it related to sharpness or tones / contrast? Do you reassign the camera (DNG) profile when you open the dng image in Lightroom? Usually the default profile gives muddy colors / tones.

[JimAscher]

Is it related to sharpness or tones / contrast? Do you reassign the camera (DNG) profile when you open the dng image in Lightroom? Usually the default profile gives muddy colors / tones.

My curiosity (and technical expertise) do not carry me for now beyond the point where I see that the DxO tiff rendering gives me more desirable (satisfying) tones/contrast than the DxO dng rendering.  The sharpness between the two may be the same.  I haven't zoomed to 100% or so to really compare.  Any reassigning of the dng profile is not so far of much interest/concern for me because of my current satisfaction with the tiff rendering.  Thanks for your continuing interest in my situation.   

[JimAscher]

I am returning to this thread (which I initiated) to report on subsequent changes in my gear which have further determined my options between rendering DxO in either tiff or DNG. 

1.  I am now working primarily with a Sony NEX 5n with legacy lenses, in Black-and-White.

2.  I have acquired a Voigtlander 15mm lens (as well as a Voigtlander 25mm lens).  On the NEX, the effective focal length of these two lenses is 24mm and 40mm respectively. 

3.  As both these lenses, but the 15mm (24mm) especially, are prone to vignetting, I must now selectively employ CornerFix to resolve that issue as needed (where cropping of the image or a preference for some minor vignetting preclude the need for corner correction).  In Black-and-White, magenta color shift is of course not an issue for me.

4.  As CornerFix only works with DNG files, DxO conversion into DNG rather than Tiff therefore becomes necessary (at least for photos taken with the 15mm Voigtlander, if not also perhaps for those taken with the 25mm).

My initial query has therefore more definitely been resolved.

[Ligament]

Would somebody kindly clarify this for me:

In DXO Optics Pro 7:

JPG will output to sRGB or Adobe RGB, but not ProPhoto RGB even if ProPhoto RGB is chosen as the ICC profile
TIFF will output to sRGB or Adobe RGB, but not ProPhoto RGB even if ProPhoto RGB is chosen as the ICC profile
DNG will output a linear gamma DNG file, which can then be opened in PS or LR and the ProPhoto colorspace can then be applied.

Do I have this right?

I do on occasion use DXO Optics Pro and want to work on the outputted files in PS or LR using ProPhoto color space.

[Sigi]

Hello Ligament,

I just tried it on DXO 7. I can create jpgs and tiffs in ProPhoto RGB. You are correct regarding DNG.

Sigi

[walter.sk]

My curiosity (and technical expertise) do not carry me for now beyond the point where I see that the DxO tiff rendering gives me more desirable (satisfying) tones/contrast than the DxO dng rendering.  The sharpness between the two may be the same.  I haven't zoomed to 100% or so to really compare.  Any reassigning of the dng profile is not so far of much interest/concern for me because of my current satisfaction with the tiff rendering.  Thanks for your continuing interest in my situation.   

I have been processing my DxO-converted images so that I get a DNG and a 16-bit tiff simultaneously, which I import back into LR4.3.  I have noticed that the DNG files consistently have less contrast and saturation than the tiffs, even though they are processed from the same file.  I haven't noticed a difference in sharpness.