How to acheive Photoshop's Curves "set white point" by picker function (in Photo V2)?

[RandomBits]

I am very new to Photo V2, so learning a few differences to Photoshop methods (that I have used for a long time).

A very basic function I need all the time is to be able to set my "white-point" (which is via the Curves adjustment in Photoshop), for document scan cleanups, etc.  As I am often cleaning up grey-scale documents, the fact the colour tinting is also being adjusted in the function is not so much my concern - but I need to be able to determine what on the page is the white-point I want by Picker selection.

Is there a function or work-around on Photo V2 to acheive this?

Thanks.

[thomaso]

Hi @RandomBits,
Welcome to the Affinity Forums!

In APhoto's Photo Persona the "White Balance Adjustment" window offers a "Picker" option. Below a V1 screenshot.

[Ldina]

@RandomBits The Curves dialog in AP2 does not have the white, gray and black selectors like in Photoshop. 

I'm not exactly sure what you want to do, but you mention working on grayscale documents (I assume you mean a scanned, monochrome image, scanned in RGB mode?). If so, you can do two quick things.

1. Add a Channel Mixer Adjustment Layer and set the mode to Grayscale. This will perfectly neutralize the image so it is all perfectly neutral.

2 Add a Levels Adjustment Layer. While Moving the White Slider, hold down Opt/Alt, and you will see when white point clipping occurs. You can do the same with the Black slider to control the black clipping point. If you don't want to set them to pure black and pure white, you can adjust accordingly. Or, use a Threshold Adjustment Layer to identify the darkest and lightest portions of the image and insert a "Sampler Point" from the Info Panel. Then, you can adjust these points to your desired levels by watching the readouts in the Info Panel.

If that's not you intent, please provide more information on exactly what you want to do. There are other ways to do the above as well..

[R C-R]

5 hours ago, thomaso said:

In APhoto's Photo Persona the "White Balance Adjustment" window offers a "Picker" option. Below a V1 screenshot.

It's there in V2 as well. It's function & options are mentioned in the WB help topic.

[RandomBits]

Ldina : Yes, I was looking for the white, grey, black 'point' pickers in PhotoV2 (which sounds like it's not there).
I will try an Action for what you have listed and see if that helps the workaround.    

To update/answer other responses so far. It's not so much "white balance" that I am after, but the setting of where I want the "white/st point" to be (with or without colour balancing involved) - so that the image curves/levels (whatever technical requirement) are ramped up or down to this point and stretched out accordingly.  That's the most non-techno way I can describe what the Photoshop version is doing.  I assume it's also adjusting the white balance in the same process, although I am not often so concerned with this part of it.

What could take me 5 seconds to do normally... ie. once image is open, CTRL+M, select the "white picker" and then select on the visual image/photo what I know should be white. Done.  Yes, I might then often also play with the Curves (as it's in the same pop-up window) and increase Gamma to contrast black-to-white range.

The "picker" in the "white balance" pop up doesn't crush or expand the white-point, it just tries to correct the white-balance. This is a more limited affect on the process I do, as I cheat the "white-point" by finding a dirty grey (or colour) that is above the visible on image white, which essentially crushes down the mid-tones to meet that point. I end up with a very clean (less dirty/noisy) document greyscale on the edges due to light/scanning/whatever issues.

I could achieve it through dragging in the Curves (with the same CTRL+M key & popup), but it's not the same simple process.  When I can decide visually what I want to wipe out on the image, and then choose another grey higher up (in tone) and then again, until I get the correct output based on several very particular pixels or shadows, etc... it's much easier than just trying to get the dragged in end point to the edge histogram and trying to guess what I am trying to remove (in terms of the particular pixels/shadows).

That said, I will try this method and see if it helps with the output I need.
 

[RandomBits]

It's function & options are mentioned in the WB help topic.

8 hours ago, R C-R said:

It's function & options are mentioned in the WB help topic.

After posting my response, and rereading your comment (I had previously already viewed the help page you referenced)... I noticed that the help page talks about "Photo Persona" & "Develop Photo".  I didn't notice this (or really understand what that meant before), but it seems "Develop Persona" has a white-point function.  I will check that out.

EDIT:  I can't locate a "white-point" picker or any other form of option in the "Develop" section.  It had some other controls and details, but essentially makes a super simple function very complicated to replicate by human eye/understanding of compounding sliders, etc... hence wanting to use a computer.  Anyway, I will play around with Persona and the standard Curves gamma function as it's essentially in there, but no automated assistance.

Edited June 20, 2024 by RandomBits

[carl123]

15 minutes ago, RandomBits said:

I can't locate a "white-point" picker or any other form of option in the "Develop" section.

It's in the Tools Panel (far left of screen)

[RandomBits]

I noticed the "white balance", but as mentioned this is different to "white-point", which is used in the help and on screen Help Info.  Unless I am missing something, I think it's a difference in wording.  I tried it on my document image, went to a 25% grey tone pixels, "clicked" (selected a pixel) as the white-point and it doesn't seem to shift to become white?  I noticed on some near white/grey tones, it seemed to adjust some shimmer of the tones slightly, which I think is more about it doing a "white balance" adjustment (not setting the "white point" as it indicates)? 

EDIT : My perspective is from 20+ years of Photoshop, so I use "white point" wording (or "set white point") as a Photoshop term, which they use in the Curves tool, along with the white balancing features of it... hence, I was assuming PhotoV2 being after Photoshop, that Affinity was using various similar Photoshop methods/wording... but not in this case?

Edited June 20, 2024 by RandomBits

[Ron P.]

Affinity Photo does not have a White or Black Point Picker. The closest to that is in the Develop Persona. The Brightness Slider is for setting the White Point/Whitest, and the Black Point Slider of course for setting the Black Point, ie; darkest.

I use these in conjunction with the Highlights and Shadows sliders. I try working the above before touching the Exposure.

It's been several years since I used PS, but I do still have the last perpetual licensed LR, and will occasionally use it. Like AP, it does not have the White and Black point pickers.

 

[Ldina]

@RandomBits As mentioned, there is no equivalent to the White, Gray, Black picker in Affinity Photo. There are many ways to accomplish the same thing, but no 'single click' solution (that I know of anyway).

One option is to use the Auto Levels or Auto Contrast buttons in the context toolbar of the Photo Persona (shown in the attached screenshot). Auto Levels forces the lightest pixel to pure white (255/255/255) and the darkest pixel to pure black (0/0/0). It does both at the same time. Auto Contrast adjusts per channel contrast and is a little different from Auto Levels. These Auto filters need to act on a "Pixel Layer", so if you apply them to an "Image Layer" (which is designed to be immutable), the filter will first rasterize the Image layer and turn it into a Pixel layer. 

In the screenshot of the duck, I used a Threshold Adjustment to first identify the darkest and lightest points in the image and set Sample Points in the Info Panel. That was just for illustration purposes, to show what Auto Levels does. Then, I used Auto Levels. This set the lightest point in the image to 255/255/255 and the darkest point to the back 0/0/3 (obviously, I didn't pick the exact darkest pixel in the image, which would be forced to 0/0/0). 

I often use Levels in the Photo Persona and move the white and black sliders while holding down the Opt Key to assess white and black clipping. But, this does not equalize the values of all three channels. It identifies where ALL 3 channels are clipped. I also use curves in the same way, but Curves does not show clipping. I often use Sampler points on white and black points (or other colors) so I can adjust them as desired. 

I think that, and the tools mentioned in the other posts in this thread, are how things are currently done in AP. FWIW, I'd like to see similar White, Gray, Black pickers at some point, but I have learned to do things differently with the tools Affinity offers.

Edit: BTW, I typically start with RAW digital camera images and make adjustments to WB, white and black luminosity, etc, in the Develop Persona, as Ron P and Carl123 have shared. Once in the Photo Persona, I may choose to adjust the WB and/or RGB endpoint values on a per channel basis, usually with Curves. Adjustment layers are non destructive. I almost never use the Auto adjustments because they are destructive and alter the numbers on the targeted pixel layer, but I thought you should know about the option. I'd be more inclined to consider Auto features on scans (which are already pixel layers), but even then, my normal approach is to do things non-destructively. There are many tools to achieve your end goal, but the white/gray/black picker tool you are used to using doesn't exist in AP. Just trying to give you some options to consider.

 

[RandomBits]

9 hours ago, Ldina said:

There are many ways to accomplish the same thing, but no 'single click' solution (that I know of anyway).

Thanks for bothering to outline your thoughts in more detail.   I went back and tried what you said about the Levels and yes, that will have to do for now.  I tried a Macro and set it up to set Auto Levels and then a Levels adjustment layer to 80% on white level.  This allows me to open a new document page, run the macro as a default attempt and I can then tweak the 80% adjustment or play around in that Levels control.

Thanks (and to others with their input on options).

Edited June 20, 2024 by RandomBits

[Ldina]

@RandomBits You're welcome!