Color Balance

Moderator: jsachs

Dieter Mayr
Posts: 450
Joined: April 24th, 2009, 11:47 am
What is the make/model of your primary camera?: Nikon D700
Location: Salzburg / Austria

Re: Color Balance

Postby Dieter Mayr » October 1st, 2016, 10:42 am

Doug,

There may be some purists who think otherwise, but to my understanding a 16 bit TIFF is as good as a RAW file.
Modern Sensors deliver 12 or 14 bit color depth, so a RAW file can not hold more color resolution per pixel then a 16 bit TIFF file can.
If you take a picture under extreme light conditions like a natrium vapor lamp or some other gas discharge lamp the sensor will
always have fewer information in some colours then others, so you always loose some quality, no matter if you color correct in RAW or TIFF.
As I wrote above, I select a white balance setting in Capture NX that looks OK for me, some white balance setting has to be chosen anyway
when converting from RAW to TIFF, so why not choose the one that is more or less OK, and I do the fine tuning in PWP.
Much more important then the white balance is to choose a big enough colour space, it doesn't help to have all the 16 bit color depth, and then squeeze it into sRGB.
Dieter Mayr

den
Posts: 688
Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: Color Balance

Postby den » October 1st, 2016, 10:54 am

...
Dieter wrote:
White balace - Giving a try with auto, often it is good, often it kills that warm light in morning or evening that I like.
So mostly a slight correction, if any is mostly enough for me.

To use the Color Balance transform to expand/check for full range and remove black/white points color casts, yet preserve magic hour mid-tone lighting (white balance)... ...try using an Inverted mid-tone range Luminance mask with perhaps a Smooth curve: 0,0 5,0 65,100 95,0 100,0 ...
Screenshot (3).jpg
Screenshot (3).jpg (50.87 KiB) Viewed 926 times

As the Color Balance transform uses the RGB color space model, a Luminance mask will give a nuance difference to the default HSV-V mask of the Mask Tool - Brightness curve.

A Luminance mask may be created by Extract-ing the image's Luminance channel and forming the mask on it, then using that as the Amount Mask of the Color Balance transform...

...den...

jsachs
Posts: 1213
Joined: January 22nd, 2009, 11:03 pm

Re: Color Balance

Postby jsachs » October 1st, 2016, 1:04 pm

While the camera WB setting does not affect the raw data, the setting is recorded in the image metadata, so most raw converters provide an option to let you set the WB to match the camera WB setting, or you can override the camera WB and set it manually. Personally, I keep my camera WB set on Sunny as this preserves the quality to the illumination, be in sunrise, sunset, north light or mid-day sun. While this works well for the kind of landscape photography I mostly do, if you were shooting portraits you might be more concerned about accurate skin tones. Similarly, if you are photographing objects for a catalog or to otherwise document how they look, you would want to apply corrections such as WB -- or you could go all the way to creating a custom camera profile for the lighting conditions you are using.

As long as you are working with 48-bit color, it should not make much difference whether to color balance in the raw converter or using the Color Balance transformation. The main difference is the user interface.
Jonathan Sachs
Digital Light & Color

doug
Posts: 86
Joined: April 24th, 2009, 10:06 am
What is the make/model of your primary camera?: Nikon D-500
Location: Toledo, Ohio USA

Re: Color Balance

Postby doug » October 1st, 2016, 3:42 pm

Jonathan Sachs wrote:
"As long as you are working with 48-bit color, it should not make much difference whether to color balance in the raw converter or using the Color Balance transformation. The main difference is the user interface."

Thanks, Jonathan. That's exactly the information I was seeking. I was worried that if you did not complete the WB adjustment while still in the raw converter with direct access to all the raw data, then the saving of a rendered image (48-bit color tiff) might discard some of the data not necessary for that particular rendering (say, it was camera WB) and thereby shortchange you on the data that might be important to a subsequent stab at further adjusting color balance. Your posting says it doesn't make "much" difference and that's good enough for me. I'm a happy camper with this information.

Doug

Robert Schleif
Posts: 66
Joined: May 1st, 2009, 8:28 pm

Re: Color Balance

Postby Robert Schleif » October 2nd, 2016, 5:21 pm

In the raw converter do the transformations of conversion, color correction, and sharpening commute? Are there situations where they do and don't commute?

jsachs
Posts: 1213
Joined: January 22nd, 2009, 11:03 pm

Re: Color Balance

Postby jsachs » October 2nd, 2016, 6:06 pm

Within the raw converter, operations are always performed in the same order.

Once you exit the raw converter, the order of operations can make a difference that can be anywhere from invisible to major. The biggest problem is transformations that discard information such as cropping, converting to 8-bit, applying curves with areas whose slopes are nearly horizontal or vertical, converting color to monochrome, compressing the dynamic range, or clipping highlights or shadows. Reversing the order of sharpening and color balancing for example will probably not make a difference you can see. On the other hand, switching the order of a Posterize transformation and a Sharpen transformation can make a big difference. While there is no general rule, it is usually safe to perform sequences of small changes in any order. If in doubt, you can always try it both ways and subtract the two result images (Transformation/Special Effects/Difference) to see where the differences are.
Jonathan Sachs
Digital Light & Color

den
Posts: 688
Joined: April 25th, 2009, 6:33 pm
What is the make/model of your primary camera?: Canon EOS-350D/Fuji X100T
Location: Birch Bay near Blaine, WA USA

Re: Color Balance

Postby den » October 2nd, 2016, 10:49 pm

...
Perhaps the impact of high content Fringing/Chromatic Aberration should also be considered and reduced before making major changes in Color Balance and Sharpening... ...for RAW files with this content using the PWP Raw Dialog, Fringing/Chromatic Aberration reductions will have to be made post-RAW conversion... ...so Raw Dialog settings for Color Balance and Sharpening changes for these types of images should perhaps be initially minimal...

...den...

Charles2
Posts: 161
Joined: November 24th, 2009, 2:00 am
What is the make/model of your primary camera?: Fuji X-Pro 2
Contact:

Re: Color Balance

Postby Charles2 » October 4th, 2016, 8:10 pm

Just to restate the main point here, the basic operation of a raw developer is demosaicing: it takes the data that the camera recorded through a color filter array (almost always Bayer, but Fuji X cameras use Fuji's X-Trans array) and creates an R,G,B triplet at each pixel. Then post processing manipulates the triplets. I have not observed a penalty for bringing a TIFF into PWP from another raw developer and changing the color balance. (Sigma's Foveon cameras are an exception - and a truly formidable challenge in post processing.)

If you want temperature and tint sliders, you can use Raw Therapee as your raw developer, but you can also raw develop on PWP, save a TIFF, open it at any stage in your post processing in RT and make changes, save a new TIFF, and bring it back into PWP. Raw Therapee is a donation-only program.

It is very difficult to duplicate camera JPGs exactly. However, you can try this: do your work in PWP, open the camera JPG in PWP, and compare by eye while you try various transformations. You can use color probes in this process, too. Be sure the camera JPG has been converted to your working color space. The effort will not be completely successful, but along the way you will probably learn what you really want, and after awhile you prefer your own style to that of the camera.


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