Thank you, Mr. Pascale!!! That was crystal clear. Now, Thomas, what did you have in mind when yuo asked the original question? What application? Why do you need to distinguish the two color difference metrics? I'm interested... / Roger Breton www.graxx.ca (still only in French, I know...) -----Original Message----- From: colorsync-users [mailto:colorsync-users-bounces+graxx=videotron.ca@lists.apple.com] On Behalf Of dpascale Sent: Thursday, December 14, 2017 9:43 AM To: 'Thomas Richard' <trichard@richard-ebv.de>; colorsync-users@lists.apple.com Subject: RE: Delta H Calculations Thomas, The usual nomenclature for this space is L*C*h Deltah is not the same as DeltaH* (or DeltaH*ab as it is sometimes referred to in regards to the CIELAB color difference). Deltah is the difference in angle while DeltaH* is the contribution of the angle difference to the total error, and is equal, for the CIELAB color difference (DeltaE*ab) to: DeltaH*ab = SQRT(DeltaE*ab ^2 - DeltaL* ^2 - DeltaC*ab ^2) Danny www.babelcolor.com -----Message d'origine----- De : Colorsync-users [mailto:colorsync-users-bounces+dpascale=babelcolor.com@lists.apple.com] De la part de Matthew Finlay Envoyé : 13 décembre 2017 00:00 À : Thomas Richard; colorsync-users@lists.apple.com Objet : RE: Delta H Calculations Thanks Thomas, So just to clarify, Am I correct in assuming from the below that DeltaH is the absolute value between each H value in the LCH color space? -----Original Message----- From: Thomas Richard [mailto:trichard@richard-ebv.de] Sent: Wednesday, December 13, 2017 12:48 PM To: colorsync-users@lists.apple.com; Matthew Finlay <mfinlay@sb-media.com.au> Subject: Re: Delta H Calculations Hello Matt, look at Bruce Lindblooms homepage: http://www.brucelindbloom.com/Eqn_Lab_to_LCH.html MfG Thomas _______________________________________________ _______________________________________________ Do not post admin requests to the list. They will be ignored. colorsync-users mailing list (colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/graxx%40videotron.ca This email sent to graxx@videotron.ca