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UltravioletPhotography

White balance (WB) and RAW-development


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My two last posts have triggered some discussion about the white-balance that I do, because the colours appear very different from those that are show in this article, for example:

http://www.ultraviol...s-reproducible/

I was puzzled, because even if I set the white balance in my camera (Panasonic Lumix G1, broadband modified) against a PTFE target, my UV-colours looked very different. However, I noticed that the JPGs embedded in the raw files came much closer to the colours that others get.

So, today I set my camera to record RAW and JPG in parallel, and compared them afterwards. The RAW files were converted with Adobe Photoshop Lightroom 4. All images were taken with an EL-Nikkor 80 mm /f5.6 with sunlight and the Baader-U 2” filter.

 

Here’s the JPG created in the camera, with only slight manual corrections:

 

post-14-0-79398500-1367620537.jpg

 

And this is the “white balance” I get in Lightroom 4, with the WB-setting “as shot”. I have tried to change the settings like camera calibration and others but I didn’t manage to create an image that compares to the in camera JPG, so far. By the way, using Camera Raw in PS5 produced essentially the same result as Lightroom.

 

post-14-0-83326700-1367620566.jpg

 

Finally, I decided to try a second RAW-converter and used UFRAW, which is a plugin for the GIMP, public-domain image manipulation software. The result is shown below:

 

post-14-0-82015800-1367620582.jpg

 

As long, as I leave the WB at “camera setting”, it looks pretty much like my in-camera JPG, which is precisely what I would expect a RAW converter to do. I cannot tell for sure that the whole issue is not caused by some strange setting of my program installation, but it seems pretty clear the RAW-conversion I’ve been using so far does have a significant impact on the UV-colours that I’m getting.

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Andrea B.

Nicolas, I think that perhaps what you are seeing here is that Lightroom and Adobe Camera Raw cannot read or properly interpret all the Lumix Raw file settings. We know that many editing apps cannot read all proprietary Raw info. For example, we have a lot of experience seeing this for Nikon Raw NEFs. Only Nikon's own Capture NX2 can give a Raw NEF the rendering that looks exactly like the Jpeg rendering.

 

So there really is nothing "wrong" with what you are doing!!! It is simply that you must take your Raw file and do some further white balancing in your chosen Raw converter/editor. Typically this would be some kind of "white dropper" or "white balance marquee tool" that is applied to some area of the Raw file. Each editor/converter has its own way of doing this kind of thing, so it is difficult for me to recommend the precise way of accomplishing the further bit of white balancing needed to pull your Raw into looking the same as its corresponding Jpeg.

 

If your Lumix came with a Raw editor, usually a SilkyPix app, then I think you might be able to open your Raw in that and see it immediately look like its corresponding Jpeg. However, everyone usually hates the SilkyPix app, so I can understand your not wanting to use it.

 

I am away from home currently, so I do not have my Lumix GH1 at hand to perform an experiment to confirm what I mentioned in the first paragraph. But if Bjørn does not get to it first, I will try the experiment when I get home next week. Meanwhile, try what I said about a further white balance effort on your Lumix Raw and let us know if you can get the "proper" UV colours to pop out.

 

As I indicated somewhere else, all UV colour is false colour. So you are always free to use the UV colour schema that you find pleasing. Bjørn and I were eager to standardize our "look" for this website because we have many of the same flowers shot at different times with different cameras and different lenses. We felt such flowers should look the same.

 

There are variations in our standardized look with respect to saturation. And we have some minor variations in the blue colours. But basically we get yellow, blue and on occasion some dark green (or perhaps it is a dark cyan, I'm not sure). And that's it - no red, no magenta, no orange.

 

BTW, white balance can always be accomplished in the converter/editor. It is not required to shoot UV with a pre-white-balanced setting. However, it is advantageous to do so because usually you can attain a better exposure by shooting as close to "correct" white balance as possible. It is much easier to judge the shadows depth and how far the brights are from blowout if white balance is correct. With Nikon cams, you never get complete white balance in a modified camera. With Lumix, as you have seen, it is possible.

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Andrea B.

Ah, we were in luck tonight - I had a disk with me that had some old Lumix GH1 shots on it.

So I have "proof" of my proposed theory (first paragraph in preceding post).

 

I located a GH1 shot made with a proper in-camera white balance.

Here is the Jpeg version of that shot - shown with no edits except resizing and sRGB.

P101007401.jpg

 

I then took the Raw Rw2 version and opened it in Adobe Camera Raw with the white balance set to "As Shot".

I saved this with no further edits and changed it to an sRGB, resized Jpeg.

You can see that ACR did not properly interpret the Lumix Rw2 white balance settings.

P101007402.jpg

 

Now, is there a remedy for this ACR behavior? I do not know, but someone else might.

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Many thanks, Andrea for your comprehensive replies and for the effort of running your own Lumix RAW through ACR.

It helps a lot to know that this is the default behaviour of the RAW converter.

So, I haven’t tried SilkyPix, but GIMP seems to work just fine. At least I do have a way to rescue the in-camera WB until I figure out how this can be done in LR/ACR.

Best, Nico

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You might want to try Corel Aftershot Pro. It handles the Panasonic RAW (.rw2) in an excellent manner. Camera settings survive untouched.

 

PhotoNinja has become the de facto conversion standard to which Andrea (willingly) and myself (relucantly) subscribe. It has the best ability to set precise and reproducible white balance for UV captures.

 

ACR obviously does not work well. I think it simply refuses to lower the implied colour temperature to around 2000 K. So you are left with a strong reddish magenta cast.

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Andrea B.

Nico, you are quite welcome.

 

The interesting thing - or perhaps disturbing thing - about the ACR conversion is that I am unable to further white balance my raw Rw2 photo. As mentioned, there are some converter/editors which ignore proprietary settings - but typically white balance can be performed anyway. Given that Lumix is such a popular brand, I was surprised that ACR (or Lightroom) cannot interpret the Rw2 files well. But Adobe is all about the average photo and not so willing to accomodate the extremes. They have just gotten too big, IMHO.

 

I always encourage everyone to learn other converter/editors. It's not that difficult. Download a free trial of Photo Ninja or Aftershot Pro and play around to see which one works well for you. Of course, if Gimp works, then use that to convert, white balance, save as a TIFF and then bring into Photoshop for further edits as needed. Or set up the horrible SilkyPix just for the conversion/wb step and then move to PS.

 

oh, just remembered - Iridient Developer is also a very, very nice converter editor with many more features than Photo Ninja. I just verified that it brings up my Rw2 in the (almost) correct white balance. There is a nice white-dropper which lets you refine the WB. The dropper can be set to different sampling sizes up to 101x101 pixels.

 

Added: Iridient Developer measured the temperature/tint of the white-balanced Rw2 as 1667K/-150. Wow!!

 

Let us know what works out for you.

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Thanks again, to both of you. I'll do some more testing and let you know what comes out.

For UFRAW/GIMP my impression is, that the noise handling is not ideal, so I will certainly look further.

With SilkyPix the WB is fine, but I'm not sure if I can live with the UI.

 

By the way, I've posted photos (VIS, UV and "bee-colours") of Myosotis sylvestris (a cultivated variety) on my blog. It is the only species that I have found, so far, where flowers of different age have a significantly different UV reflection. Since it grows in my garden, I have verified this several times by now.

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All Myosotis species appear to have the changeable UV behaviour as the flowers age. See this example for M. sylvatica

 

The photos of M. sylvatica demonstrates this variation holds also for albino flowers.

 

I haven't gone through available material for other genera of the Boraginaceae to verify whether altered UV behaviour occurs. I am pretty certain Pulmonaria spp. do not exhibit this phenomenon, though.

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  • 2 weeks later...

 

Let us know what works out for you.

 

... I’ve been quiet for a while, since I was busy with all kinds of stuff. However, I’ve tried Photo-Ninja, which is fine but would require me to change my workflow.

Finally, after some attempts I could get a kind of remedy using the DNG_Profile_Editor:

http://wwwimages.adobe.com/www.adobe.com/content/dam/Adobe/en/products/photoshop/pdfs/cs6/DNGProfile_EditorDocumentation.pdf

I’ve been pointed to that in two different user Forums, (Luminous-Landscape and Adobe’s own). I’m still evaluating, but I’m getting colours that are very close to the in-camera jpgs.

I’ll be posting some examples soon, when I have some more experience.

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PhotoNinja is just an example of a RAW conversion program that handles the required UV-white balancing in an excellent manner. It is reliable but not to everyone's liking for sure.

 

On a recent joint trip, Erik Lund pointed out to me out that Capture One also did the UV w/b well. This was for NEFs from his UV-modified Nikon D300 (Precision U filter inside).

 

So there are alternative roads to Rome (or UV white).

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Don't be afraid to change your workflow!!

 

It is not difficult to learn other editors. User interfaces only seem "bad" because of our unfamiliarity with them. I switch between several editors depending on what I need to edit/process. After a couple of weeks of getting familiar with a new one, it becomes easy. After all, there are only so many things we can actually do to a photo and all of the converter/editors do most of them.

OK, end of Pep Talk. :)

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"User interfaces only seem "bad" because of our unfamiliarity with them."

 

Now that is a blanket statement which I simnply cannot endorse. You pretty soon find out what interfaces are "good" or "bad", for example, based upon whether they minimise mouse movements or allow setting hot keys. One should be able not only to do editing and batch processing but also a minimum of file manager chores (moving, copying, renaming based upon EXIF etc.) in a good program. The less need to switch between programs the better the work flow.

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I guess that stuff doesn't really bother me all that much. I routinely switch between programs and usually have NX2, Photo Ninja, Photoshop and Photo Mechanic all running simultaneously with Raw Developer and Photivo on call as needed/wanted.

For file manager chores, I have been using Photo Mechanic, prefering to have that functionality outside a converter/editor.

I don't use a mouse at all - just the touch pad and customized keystrokes.

 

But no matter - there is so much out there that surely everyone can find a converter/editor

which pleases them and works for them.

I simply wanted to encourage folks not to be afraid of changing and learning.

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