Anaglyph HALD Generator (Anahald) - Impact of HALD LUT-s on human skin colour appearance
(this page has dark background to improve viewing experience with anaglyph samples)
By Oleg Kosyakovsky
This page shows how different anaglyph conversions - standard and Anahald-based - convey skin colours on the de-facto standard test image lenna.png .
Well, instead of the original planar image, its 2d-to-3d conversion by IMGonline.com.ua (https://www.imgonline.com.ua/eng/stereoscopic-3d-picture-from-photo.php) is used.
|Left-Above:::::Anaglyph-option-Half-Color - - - - -> Anaglyph-option-Dubois:::::Right-Above|
|Left-Above:::::Anaglyph-option-Suto - - - - -> Anaglyph-option-SPM:::::Right-Above-Above|
|Above::::: - - - - - - - - - - - The-original-stereopair - - - - - - - - - - - - - - - - - :::::Above|
|


|Left-Above::::: Anahald-anaglyph-Color-Preserve/gamma=1.0 - - -> Anahald-anaglyph-Moderate-Correction/gamma=1.0 - - -:::::Right-Above|


|Left-Above::::: Anahald-anaglyph-General-Purpose/gamma=1.0 - - -> Anahald-anaglyph-Eye-Comfort/gamma=0.9:::::Right-Above|


|Left-Above::::: Anahald-anaglyph-Small-Flowers/gamma=0.85 - - -> Anahald-anaglyph-eXtreme-Correction/gamma=0.85 - - ->:::::Right-Above|
Observations from the above comparison - the author's take:
- Differences between the conversions are less pronounceable when viewed through red-cyan glasses.
- StereoPhotoMaker-"Dubois" and undocumented StereoPhotoMaker-"SPM" options are off.
- StereoPhotoMaker-"Half-color" option appears fine at the first glance because the face looks good; but do notice the shoulder becoming wax-colored.
- Undocumented StereoPhotoMaker-"Suto" option looks good.
- Anahald-"Color-Preserve", Anahald-"Moderate-Correction", and to some degree Anahald-"Eye-Comfort" look good also.
- Anahald-"Color-Preserve" is nearly indistinguishable from StereoPhotoMaker-"Suto".
Now let's put all the usable options side-by-side for the final glance. This time Anahald-originated conversions are made darker for more fare comparison with the StereoPhotoMaker-"Half-color" variant.

|Left-Above:::::Anaglyph-option-Half-Color - - -> Anaglyph-option-Color-Preserve/gamma=0.8:::::Right-Above|


|Left-Above::::: Anahald-anaglyph-Moderate-Correction/gamma=0.8 - - -> Anahald-anaglyph-Eye-Comfort/gamma=0.7:::::Right-Above|
To be honest, the model's skin has a very similar appearance on all the four conversions when viewing through the author's DIY dual-film-filter glasses.
With "Nvidia 3d-vision discover" glasses, the advantage of Anahald-based options is subtle, though undoubtedly apparent.