How does each software/program white balance images?

[Stefano]

I had a quick thought that I think might be interesting. I searched on the forum, but I didn't find something similar. I remember when I asked someone to white balance a test image I created to see the result (here). When I did this I wanted to prove something else (read that topic), but now, having the possibility to white balance my images myself (using IrfanView), I wondered if there was a difference. I already had some doubts about how well can IrfanView white balance, and I noticed the odd results I obtained several times. In particular, I had "different-than-normal" results here.

 

My test image (made in Paint, nothing special) consisted of three squares with three colors I think are commonly see in RAW UV images, or UV images that are not white balanced. They are, from left to right, bluish magenta (basically purple) (128, 0, 255), magenta (255, 0, 255) and reddish magenta (255, 0, 128).

 

I asked someone to white balance it in the middle square, and Birna did it. She obtained colors I would expect in a UV or IR image (more IR than UV):

 

Measuring the colors in Paint, I have, from left to right: (121, 155, 252), (249, 248, 246(?)) and (250, 232, 108). She did the white balance in Photo Ninja, but had to convert the image to .jpg in Photoshop, and said that could have altered the colors just a bit.

 

Below is an old IR image I made with my 730 nm and 850 nm LEDs, white balanced in-camera:

 

The colors are kind of the same.

 

But here is the interesting point: what happens if you take the same initial image, and white balance it in IrfanView?

 

You get this:

 

Way different. The colors are (42, 170, 169), (170, 170, 170) and (170, 171, 43). I don't think most of us would like UV images with those colors, even though they could look interesting.

 

My question is: can you (all) white balance my initial image with other programs you have, post the result and write the RGB coordinates you got? This could be useful to see how well the most common softwares white balance images.

[Cadmium]

You would need to provide a RAW file.

[nfoto]

Steve has a good point. W/b on jpgs don't work well. Stefano's example, however, has very little fine detail, so will perhaps not throw off all software. However, it is introducing an unknown into the equation as it were.

[Andy Perrin]

JPG issues aside, you shouldn't be comparing RGB components, you should be looking at a* and b* values in the L*a*b color space, since those correspond to what we see visually.

[dabateman]

Stefano,

There are a lot of free editing programs. You don't have to limit yourself to Infran viewer. Also Olympus Workspace will work with any camera jpeg file and has a good color editor. If you need a camera serial number just pull a em5mk2 one off an Ebay ad. Thats what I do.

Try:

Lightzone, RawTherapee, Gimp, krita, photoscape x, inkscape, photo flow, photivo, darktable, chasys draw ies, image j, picture window pro 7 and Art (a fork of Raw therapee)

Raw only: ufraw

[dabateman]

Luminar 3 has amazing settings to edit IR images that they abandoned in later versions. You may still be able to get a free code.

 

How to edit infrared in luminar 3

https://robertreiser.photography/skylum-luminar-for-infrared-photography/

 

[Stefano]

Ok, thank you all. As of RAW images, is it possible to make one which is the same as my test image?

 

Also, I looked at the L*a*b space on Wikipedia, and read that the L component is the perceived brightness, and a and b are two color axis. How does this help to see what we actually see?

[Andy Perrin]

If you're trying to understand if two colors are the same, you need to compare a* and b* values, not R,G,B values, since the latter mix the colors with the brightness. a*=0 and b*=0 correspond to white/gray using the standard illuminant "D65" as they say, which is a 6504K blackbody.

 

But my main point, to get back to your images, is that the picture you took is much DIMMER than the one you are comparing it to, so RGB is not an apples-to-apples comparison. To have apples-to-apples, you are better off comparing a* and b* values. But even that is not 100% foolproof because L*a*b* itself is still only approximate to human vision (although it's close enough for casual usage).

[Stefano]

Ok, so basically with the LAB space I can see the hues only, excluding the brightness. That makes sense, as brightness here is not important.

 

It would be cool to reverse-engineer how each software does the white balance.

[Andrea B.]

FWIW, here is your image white balanced in Photo Ninja which can often white balance JPGs fairly well.

 

Given the outcome here, I'm guessing that Birna also used Photo Ninja?

 

[Stefano]

Thanks Andrea. What I would like to see (if it is of any utility for anyone) is the same done on other softwares, such as Lightroom or others (I don't remember others now). I can try the free softwares myself, but if someone has already bought the non-free ones, he (or she) can try kt for me and us.

[dabateman]

Seems like on here photo ninja is most popular. The other big expensive software options are:

DXO (I bought pro 9, got version 11 for free)

Capture one (I bought version 6, got the last Nikon only version free. Not sure if it edits any jpegs)

Lightroom (I bought version 3, have no interest in it as I don't like a folderless interface)

Luminar (I got version 3 free with my smugmug account, later they offered it free)

ON one (I got some version for free never really used it)

Photo Affinity (I got my version free when buying the color checker passport from B&H)

Those are the big ones. Topaz also has editor, but its a little painful. I spent too much money on Topaz software and still don't have a powerful enough computer to take advantage of it.

 

I even bought lightzone back in the day. Now its better and free.

 

I just never get around to using software. So have decided to stop spending money on it. I try now to nail everything in camera. Part of the reason I got a Pen-f for internal monochrome and color wheel editing live prior to the shot.