AP: Develop - Clipped Tones: Affinity-sourced explanation

[Wumpus]

Side Note: Only had purchased Photo, but tried the Designer V1 demo a couple times, but it wasn't enough for me to understand, however a couple days after v2 came out I bought the Affinity bundle, and I've been enjoying the entire suite quite a bit more. Very capable products, and continuing to mature: thank you Affinity.
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TOPIC

Affinity Photo: Develop Personae - Clipped Tones definition, and how to remediate its warnings
No rush on this topic/post, but I would still appreciate a response at some point. This seems to still be relevant for v2.

I've tried to figure this out a few times since Spring 2019, and never could get an authoritative answer (lots of well-intentioned forum generated musings, but none of which were applicable).

I do understand ETTR, and underexposed shadows and clipped highlights, but the explanation "Clipped Tones means you have too many midtones" wasn't enough for me to work with." Or here was another, "Show Clipped tones when enabled will show all the clipped midtones areas with a bright yellow colour. This then allows you to use the tools such as Exposure to adjust your image."

Based on those explanations, this is what I've deduced... "Clipped Tones are when there are so many mid-tones that they spill out the top of the histogram".   😉

In my previous quests for an explanation of this functionality and how to use it, I have found changing various settings alter the degree of the warning to various extents, but I still can't quite understand it though. Yes, I do also keep checking the help file every few months.

I encounter this warning a fair bit, and have been hoping for guidance on a way to deal it. Thank you!

[James Ritson]

I think it helps to simplify things as much as possible. In this case, clipped tones are essentially colour values that do not fit within the available output colour space (such as the default sRGB profile), usually because they are too intense.

There are a couple of solutions to this: you could change the output profile to something wider such as ROMM RGB (notice how the histogram shifts when doing so), or you can use a combination of exposure, brightness, black point, saturation/vibrance, shadows and highlights to “compress” or make the tones fit within the available range of colour values.

The first solution of using a wider colour profile does introduce potential pitfalls with colour management (such as the infamous colour shift when viewing images with a wider colour space in an unmanaged view). Most web browsers are colour managed nowadays, but it’s still often recommended to convert to sRGB during export to ensure maximum compatibility.

The second solution usually means you end up compressing the tones more, typically when using the highlights slider. This is fine, but just keep an eye on the actual image rather than the histogram—this leads me onto the next point…

Outside of some edge-case workflows (such as high end VFX), the whole concept of clipped tones lends itself to more of a creative decision—you might have some intense red and blue colour values, for example, that cannot be represented in sRGB, and so will simply be clipped to the maximum channel value. This isn’t necessarily the end of the world! You can most likely craft a perfectly good image within the constraints of sRGB as it does tend to represent the majority of colour intensity values seen in everyday life with reflected light.

I wouldn’t spend too much time worrying about it, to be honest. Does the image look good on screen in sRGB? If not, and you’re happy to involve wider colour spaces in your workflow, try a wider profile such as ROMM RGB. But don’t get bogged down with it too much! The time worrying about whether some clipped tones are compromising image quality is arguably better spent learning some useful post-processing techniques for the kind of imagery most likely to have intense colours (e.g. low light, urban scenes with artificial lighting). HSL, Selective Colour, brush work on pixel layers with blend modes are just a few ideas, but there are many more.

Hope the above is helpful!

[Wumpus]

Thank you so much, James!

This was precisely the kind of high level advice I've been hoping for. Yes, that made perfect sense and now I understand it. I see now how a creative/pragmatic balanced choice can be made when that occurs, and I will experiment with temporarily moving to a wider colour space and then play with reining the rogue colours into a more common space, or using a combo of adjacent factors to shoehorn things back into place. Bookmarking this for sure! You generously even threw in some bonus ideas. 😀

Very kind, especially amid the flurry of activity surrounding the new launch, but so very much appreciated.

Hope the weekend coming up turns out just as you'd wish!

[lacerto]

I am sorry to say but while your description of clipping of colors makes sense, and advise against obsessive gamut correction is quite sound, I cannot see much of this reflected in Affinity Photo Develop Persona (including version 2, both on Windows 11 and macOS Ventura on an M1 computer).

In Photoshop Camera RAW I have no problems using equivalent (or so I assume) controls. I do not expect these two apps to behave identically, but my problem is that I simply just cannot make this feature work in Affinity Photo practically at all.

When I use clipping and gamut warnings in context of Adobe Camera RAW, they seem to do exactly what can be expected. If I choose e.g. sRGB target profile and then use saturation, vibrance, exposure, highlights, etc. to make colors overly intense, I get highlight clip warnings that show how in the target image these tones would be clipped (returned to full channel value), and conversely with shadows, zero channel values would trigger shadow clip warning. If I change to a wider gamut profile, like Adobe RGB, those warnings disappear or the warned areas get smaller. If I choose a photographic profile involving media information, I get a gamut warning instead, showing where at least one of the channels has 0 [or 255] value and accordingly loses ability to deliver tonal variation at that point (highlights would be irrelevant because they are basically paper spots).

But when I try to reproduce this in Affinity Photo, nothing at all happens when I try to use Shadow and Highlight Clip warning toggles (only the Tones warning seems to work, and it works pretty much similarly as the Gamut warning in Photoshop). But more importantly, if I change the target profile to one with a wider (or narrower) gamut, this is not reflected in tonal warnings in any way.

There does not seem to have happened any (or much) development between the versions in this area. But perhaps I am doing something wrong, or the feature is supposed to be used only in context of certain specific workflows. Or perhaps it is limited to specific kinds of RAW files?