Ale S

CLIPPING WARNINGS IN PHOTO PERSONA USING PROCEDURAL TEXTURES
Develop persona allows you to see clipped areas. I have created three procedural texturas to reveal this areas in photo persona.

First procedural texture: Clipping Shadows/Highlights
Here is an example where shadows and highlights are clipped.

Just like develope persona i used red and blue to show the warnings. Red for highlights and blue for shadows.

Second procedural texture: Clipping RGB
This procedural texture shows warnings for each channel when a pixel reaches 0 or 255.
Each channel has its own warning colour. Single colour per channel.
In this example i went too far setting the black level on the green channel.


Usually you will only see warnings in red, green or blue but it is also possible to see cyan, magenta or yellow.
Lets take for example a yellow warning. If you add red and green you get yellow so a yellow warning refers to the red and green channel.
Cyan = Green + Blue
Magenta = Red + Blue


Third procedural texture: Clipping RGB - Black background
Sometimes its hard to see the warnings because they look they are blended whith the image.
This procedural makes the image completly black while the warnings remain in colour.
It is like when you select the levels adjustment and hold down the alt key but in this case the warnings are visible while editing each channel.

If you found this usefull you can download the file at the end or paste this formulas.
First procedural texture: Clipping Shadows/Highlights
var trigger=floor(0.5+abs(average(R,G,B)-0.5)); trigger*R + (1-trigger)*R
var trigger=floor(0.5+abs(average(R,G,B)-0.5)); (1-trigger)*G
var trigger=floor(0.5+abs(average(R,G,B)-0.5)); trigger*(1-B) + (1-trigger)*B
Second procedural texture: Clipping RGB
var rgb=floor(max(R,G,B,1-min(R,G,B))); var red=floor(0.5+abs(R-0.5)); rgb*red + (1-rgb)*R
var rgb=floor(max(R,G,B,1-min(R,G,B))); var gre=floor(0.5+abs(G-0.5)); rgb*gre + (1-rgb)*G
var rgb=floor(max(R,G,B,1-min(R,G,B))); var blu=floor(0.5+abs(B-0.5)); rgb*blu + (1-rgb)*B
Third procedural texture: Clipping RGB - Black background
var rgb=floor(max(R,G,B,1-min(R,G,B))); var red=floor(0.5+abs(R-0.5)); rgb*red
var rgb=floor(max(R,G,B,1-min(R,G,B))); var gre=floor(0.5+abs(G-0.5)); rgb*gre
var rgb=floor(max(R,G,B,1-min(R,G,B))); var blu=floor(0.5+abs(B-0.5)); rgb*blu
clipping_warnings.afphoto

What happend to that need?
Currently Affinity lacks complete colormanagement / softproof functionality.
Missing is:
1) Preserve RGB / CMYK numbers → this is needed to simulate how an RGB file will look like on a non-colormanaged RGB printer (like often in a photo lab) or how a CMYK file which will not be converted to another colour space will look in a specific CMYK space.
BTW, this option is also needed when you want to print out a (ICC color) calibration target from the Affinity application itself.
2 a) Option "Simulate Paper color" → this determines the rendering intent from the (converted) file to the monitor colour space regarding the white point:
"Simulate Paper = On" → absolute colorimetric conversion from the file to the monitor color space
                             = Off → relative colorimetric conversion from the file to the monitor color space
2b) "Simulate Black Ink" → determines if Black point compensation from the file to the monitor colour space is used or not
"Simulate Black Ink = On" → Blackpoint Compensation from File to Monitor Colour Space turned off
"Simulate Black Ink = Off" → Blackpoint Compensation from File to Monitor Color Space turned on
Affinity offers now a softproof and conversion of a file to another color space. But it lacks to control how the files are rendered to the monitor colour space!
The default rendering intent in Photoshop to the Monitor profile (color space) is: Relative colorimetric with blackpoint compensation and can be influenced like described here, which of course is a vital feature!
3) A preview for "Assign Profile" is also missing currently
4) A keyboard shortcut to toggle the softproof on / off can also be very handy and is missing now 😞
5) In Publisher I do not see an option to enable the softproof function for the complete document, but only for each page!? If that's not possible (which it seems) -- this is an additional need.
6) Exporting images: Currently there is lacking
6a) Choose rendering intent for the conversion
6b) Preview for this conversion (in the export dialog)
7) In "better" color managed programs one can also choose which CMM is used for the conversion -- which is now also lacking.
See here for the colour management options from Adobe: https://helpx.adobe.com/photoshop/using/proofing-colors.html
The Affinity programs are great in many ways, but I am very much surprised that in 2020 those functions are not standard in a software which claims / tries to aim at the professional user. All professionals, who know and care about predictable color, and know how to use color management to achieve that, will not use Affinity products till those features are implemented. I did not remember exactly in which Photoshop version this was introduced, but it was a loooooong time ago. I think the current color management features already were introduced around 2000 with Photoshop 5.5 if memory serves me right....