problem with white balance in develop persona

[rikkarlo]

Hi everyone, 
apparently in develop persona the white balance only affects the "temperature" value and not the tint, thus it does not give perfectly balanced greys automatically. 
Am I doing something wrong? is it a bug? or is it a feature?
In any of these cases how can I balance the white properly in affinity designer whitout necessarely moving manually the temperature and tint
sliders?

I provide this image as example, to reproduce the problem just click on the left area with the white balance tool in the develop persona, and you'll see that the RGB values will not be flattened out as it should be, instead the 3 values will stay different, also if you look at the sliders "tint and temperature" on the right you will see that the second won't move

[walt.farrell]

7 minutes ago, rikkarlo said:

just click on the left area with the white balance tool in the develop persona

I think you would use the White Balance Tool in the Develop Persona to click on an area that is supposed to be White, and the color cast would be removed from the other areas based on what it took to restore that off-white color to pure white. It is not supposed to give you a neutral gray. You would need a gray-point picker for that, which Affinity does not have as far as I know.

[rikkarlo]

Yea, it should do what you say, but it does not work, and btw an area that is supposed to be white in a picture (such as a wall as in the example) is always grey really otherwhise it would flatten all the values to 255 instead, which is not what the "white balance tool" should do.

[rikkarlo]

BTW in this video it shows how it should work, and you can clearly see that when he clicks on the image both the sliders of temperature and tints move together to make the whites grey, however when I do it in my affinity photo (updated at the last version btw) it only moves the top slider, the second one stays fixed in place.

[Subclavius]

Hi @rikkarlo,

In the example video by James Ritson, he's adjusting the white balance of an actual picture.  This is important because APhoto is working with the file's metadata from the camera AND the image hasn't yet been assigned to APhoto's default/working colour space.  If I load one of my images and use the white balance tool, I get both the colour temperature and tint sliders to move.

It's not clear what you are doing with your example above.  For example, did you create/pick the particular shade (183,167,152) in the normal Photo persona and then move to the develop persona?    If I do this, then I get the same result as you, namely that APhoto only changes the colour temperature.

[rikkarlo]

Yes I did exactly as you said, however I'm sure the colour space shouldn't matter, the tool should work in both cases in the same way don't you agree?

At least in photoshop it's the same with raw and non raw data, and anyway I don't see the point of making it doing different things. When should I need to balance only the temperature and not the tint? And even if I would need it how to regulate the temperature then?
 

[Subclavius]

You're right - the colour space itself doesn't matter. What is troublesome is that the white balance tool in the photo persona only changes the colour temperature when the colour picker is used but the tint is left unchanged.  This is the same behaviour as @rikkarlo observed in the develop module.  It looks like a bug at first sight but one of the moderators needs to have a look at this.

 

[rikkarlo]

Yep,
I've noticed this bug last year, I already tried to report it in the forum but nothing happened yet, I found this area of the forum only recently, I hope posting it here will make it more visible to devs. Finger crossed.
Thanks for your answer in the meantime.

[Gabe]

Hi all,

I replicate this here and logged it with our developers. 

[rikkarlo]

Thanks!
Will you post here when or if there will be news??

[Gabe]

We can't promise that we can come reply to every single bug report when it gets fixed. However, every release of retail/beta has a fix list, so when this gets fixed, it will be included in that list. 

[rikkarlo]

Cool, I'll stay updated! thanks a lot!

[David in Яuislip]

On 7/6/2021 at 8:59 AM, Gabe said:

I replicate this here and logged it with our developers. 

Are you using a Mac cos it works properly on Windows? Image shows before and after click

[rikkarlo]

22 hours ago, David in Яuislip said:

Are you using a Mac cos it works properly on Windows? Image shows before and after click

Thanks for testing it,
I'm using Windows, but I guess you are using an image with raw data am I wrong?
Try to open a .jpg picture and switch to develop persona, it does not work for me.
Furthermore the white balance adjustment layer in the photo persona has the same problem.
Ric

[David in Яuislip]

2 hours ago, rikkarlo said:

I guess you are using an image with raw data am I wrong?

No, it was indeed a raw file. However, I don't see the tint slider issue as a bug.

This is my understanding, I'm not lecturing and apologise if I'm wrong:
White balance as a temperature in K with a tint is for raw. Once those values are set, the raw data is demosaiced, interpreted according to the selected colour gamut, sharpened and output to file. Of course you can take an rgb image then move the sliders but that just shifts the colours around and not to any precise K values, note how the temp slider is now a % although I wonder what it's a % of, just a number would do

I repeated your exercise although my venerable cs2 doesn't do white balance so I used adjustment layers and the Set Gray (sic) Point pickers

I think the real problem is that the Affinity rgb values are not identical 

[rikkarlo]

I'm not sure if I completly grasped your point, but the white balance tool should correct the overal look of an image so that the areas that are picked are neutral (grey) and the rest of the image is shifted accordingly, exactly how it happens when you work with a raw file. 

According to this definition how can I do it if I don't have the raw file in the first place but only a jpg file? I didn't find any way other than manually moving the sliders, which to me is not what it is supposed to be. 

[David in Яuislip]

3 minutes ago, rikkarlo said:

I'm not sure if I completly grasped your point,

I'm not sure if I understand it properly 🙂

A raw file has 10, 12, 14 bits per pixel depending on the camera.  After conversion it's 8 bits so there is a reduction in allowable tones.

Say you have a raw file that has been developed and the tones fit within the blue line below. If you subsequently change the temp/tint or add adjument layers then the available colours remain the same but they are shifted around within the limits of the blue line. However, if you go back to the raw file then you can adjust the temp/tint to produce the red line. Note that I don't know how to prove that and maybe it's nonsense.

If you only have a jpg then you can only work with that and accept the outcome. I agree with you that the White Balance tool should change a colour to grey and affect everything else accordingly

[rikkarlo]

I see what you mean now, I guess that what you say is correct, the raw bigger colour space provides a non destructive white balance and you always can go back to adjust it non-destructively as many times as you want (provided that the blue/red areas don't clip out of the coloured triangle). 
However, I still can't get why you mentioned that the tool without raw data is not bugged, it should provide the same effect of flattening the rgb values in the colour picked area, while shifting the RGB colour values of the entire image, exaclty as it happens in the bigger colour space, with the only doun side that it might be destructive.

Anyway, I think the devs are already looking to the problem, if they will fix it we will know if it was an actual bug or a feature XD

[David in Яuislip]

Have a look at how Photolab handles this. When you use the colour picker then the colours change but the slider doesn't move. When you do similar with APhoto then the colours change and the slider moves...but to what? There are no absolute values of Temp or tint so which company is correct?

[rikkarlo]

The correct one is the one that gives you neutral colour in the picked area  no matter how the sliders move and what the numbers are .
If affinity would have performed a correct white balance I would be perfectly fine not having both sliders moving.

[David in Яuislip]

6 minutes ago, rikkarlo said:

The correct one is the one that gives you neutral colour in the picked area  

Correct 🙂

I also think that APhoto should not show the tint slider if it's not raw data. As to whether it should move or not when the colour picker is clicked I'm not sure
Anyway, I have no use for the Develop persona when editing rgb files and if I had to depend on APhoto for developing raws then I'd go back to shooting jpegs in the camera

If you want a laugh look at https://affinity.serif.com/en-gb/photo/?mc=AFFPPCGS01&gclid=EAIaIQobChMIzJH65e_28QIV04bVCh3j4gGBEAQYASABEgIb9fD_BwE
and note these two
Professional lens corrections
Best in class noise reduction and hot pixel removal

The first is tripe, lensfun is a terrific innitiative where the database is populated by enthusiastic amateurs around the globe. If you compare the corrections with Photolab then professional it ain't
The second is more marketing speak, the best noise reduction is either Photolab deep prime which is astonishing or Topaz which is highly rated on dpreview and other sites but I haven't used it

Sorry, I went a bit off topic then, it must be the heat

[rikkarlo]

Let's keep an eye on future updates and let's hope for a quick fix. In the mean time thanks for the hints .

 

[rikkarlo]

Hi everyone, any news about this one?
I'm still waiting for an automatic way to correctly white balance a jpg image in affinity.
If it is not considered as a bug anyone knows a workaround?

[Keyseeker]

Have basically found the white balance picker function useless as when I click on a known neutral gray area in a 16 bit tiff file all colors get pushed to about 30% warmer than a true neutral, This happens regardless of the file format color space, of color depth. Am I missing a calibration setting?

 

Windows 10, Intel 8700K core i7, AMD Radeon 560

[walt.farrell]

33 minutes ago, Keyseeker said:

Have basically found the white balance picker function useless as when I click on a known neutral gray area in a 16 bit tiff file all colors get pushed to about 30% warmer than a true neutral, This happens regardless of the file format color space, of color depth. Am I missing a calibration setting?

Why are you clicking on a gray area? You're supposed to click on a white area.