JoelOwens Posted April 19, 2021 Share Posted April 19, 2021 Hi, what is the difference between HSL adjustment (saturation shift slider -100 %) and Vibrance adjustment (saturation slider -100 %) when used for desaturation in Affinity Photo? The result with HSL adjustment usually appears darker. Why? Thanks. Quote Link to comment Share on other sites More sharing options...
GaryLearnTech Posted April 19, 2021 Share Posted April 19, 2021 Hi @JoelOwens I have a vague memory, from many years ago, of reading that Vibrance adjustments were tuned for human skin tones. This was, for example, to avoid unnatural orange colour casts when increasing saturation in images containing subjects with what's referred to as "white" skin. In contrast, a saturation adjustment from HSL would be applied equally (or proportionally?) across each colour channel and in each of shadows, mid-tones and highlights and could more easily result in garish adjustments. I'd assume that something similar goes on in reverse with your desaturation - throttled desaturation in vibrance, linear/proportional desaturation in HSL adjustments. Note that this recollection dates back to pre-Affinity days, referring of course to older versions of Adobe's pride and joy. Specific details might have evolved a little over the years, but probably not significantly. Quote —— Gary —— Photo/Designer/Publisher: Affinity Store, v2.4.n release Mac mini (M1, 2020), 16GB/2TB, macOS Ventura 13.4.1(c) • MacBook Pro (Intel), macOS Ventura • Windows 10 via VMware Fusion • iOS: current release Link to comment Share on other sites More sharing options...
Staff Dan C Posted April 20, 2021 Staff Share Posted April 20, 2021 Hi @JoelOwens Unfortunately we're not in a position to directly discuss the algorithms Affinity uses for the HSL / Vibrance adjustments, however we can certainly provide some more contextual information here! As Gary has mentioned above, the Vibrance adjustment is designed to 'protect' skin tones - even when set to maximum values in either direction. Therefore the Saturation slider in the Vibrance adjustment acts differently from the HSL Saturation slider, as Vibrance is using this 'protect' algorithm and HSL does not. This allows for the HSL adjustment to 'push' pixels past certain Saturation points that the Vibrance adjustment simply can't do and can lead to more extreme over-saturation/de-saturation. This is covered in the below video tutorial from Olivio Sarikas - I hope this helps! Alfred and GaryLearnTech 2 Quote Please note - I am currently out of the office for a short while whilst recovering from surgery (nothing serious!), therefore will not be available on the Forums during this time. Should you require a response from the team in a thread I have previously replied in - please Create a New Thread and our team will be sure to reply as soon as possible. Many thanks! Link to comment Share on other sites More sharing options...
JoelOwens Posted April 20, 2021 Author Share Posted April 20, 2021 Thank you very much for your explanations. I think that clears everything up. Dan C 1 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.