How to highlight 'too dark' or 'too bright' pixels

[afdojo]

In Affinity Photo, I would like to highlight pixels that are 'too dark' or 'too bright.'  I couldn't find anything in Help and Forum. I don't know what Affinity calls this feature but searched for things like 'out of gamut' and 'soft proof' and 'highlight black pixels' to no avail. Ideally, I could set thresholds (< 5 for 0-255 or <2 for 0-100 scales). As an example, I've attached a photo with dark pixels replaced with red and bright pixels replaced with blue (I wrote a python program to do this).

Thanks for your help.

Doug

[Dave.Kelly]

Hold down the J key?

[Oufti]

You could create a pixels selection using color or tonal ranges:

https://affinity.help/photo2/en-US.lproj/index.html?page=pages/Selections/selections_range.html&title=Range pixel selections

https://affinity.help/photo2/en-US.lproj/pages/Selections/selections_sampled.html

 

Or perhaps you could use some dynamic masks?

https://affinity.help/photo2/en-US.lproj/pages/LiveMasks/mask_liveBandPass.html

https://affinity.help/photo2/en-US.lproj/pages/LiveMasks/mask_liveLuminosityRange.html

 

And to see which are the RGB pixels without a CMYK equivalent, you can use the Gamut check in the Soft Proof adjustment:

https://affinity.help/photo2/en-US.lproj/pages/Adjustments/adjustment_softProof.html

 

[thomaso]

Design Aids (Develop Persona only):

• Show Clipped Highlights—when selected, highlight areas which suffer from loss of detail due to clipping are displayed on the image in red.
• Show Clipped Shadows—when selected, shadow areas which suffer from loss of detail due to clipping are displayed on the image in blue.
• Show Clipped Tones—when selected, midtone areas which suffer from loss of detail due to clipping are displayed on the image in yellow.

https://affinity.help/photo2/English.lproj/index.html?page=pages/Workspace/toolbar.html&title=Toolbar

[afdojo]

Thanks @thomaso and @Oufti! Looks likes it is time to learn about Personas. The Luminosity Mask range is also helpful!

[Ldina]

@afdojo You can display clipped (out of gamut) highlights, shadows, and tones, in the Photo Persona using a Live Procedural Textures filter. The following discussion provides Procedural Texture formulas you can load into Affinity Photo for that purpose. This provides similar display of clipping to the Develop Persona. Procedural Texture are a bit confusing, especially if you are new to Affinity Photo. I've tried them and they work. I'm not sure if this is the sort of thing you are looking for.

Another approach you can use to identify clipped tones is a Levels Adjustment Layer. While that adjustment layer is open, you can move the White Level and Black Level sliders back and forth while holding down the Opt/Alt Key and it will highlight areas that are clipped...