November 2022 - colorsync-users

DNG As Shot Neutral
by Jeff Nova 09 Nov '22

09 Nov '22

Hey there all, It's me again, poppin up like a meerkat in your inbox. I have another DNG question... See if anyone knows... The field *AsShotNeutral* (I sometimes misread this, but I'm sure I'm the only one) is defined as: "...[this field] specifies the selected white balance at time of capture, encoded as the coordinates of a perfectly neutral color in linear reference space values." Do they mean XYZ? Or are other spaces permitted? Sounds quite vague to my amateur ears. Very best, Jeff Jeff Nova Chief Executive Officer Colorhythm https://colorhythm.com Mobile: +1 510-710-9590 Main: +1 415-399-9921

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Re: colorsync-users Digest, Vol 19, Issue 45
by Jeff Nova 08 Nov '22

08 Nov '22

Thank you, Graeme!! Your generosity in sharing your knowledge is inspiring (and to be reflected! ; ) Yours, Jeff Jeff Nova Chief Executive Officer Colorhythm https://colorhythm.com Mobile: +1 510-710-9590 Main: +1 415-399-9921 On Sun, Nov 6, 2022 at 12:00 PM <colorsync-users-request(a)lists.apple.com> wrote: > Send colorsync-users mailing list submissions to > colorsync-users(a)lists.apple.com > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.apple.com/mailman/listinfo/colorsync-users > or, via email, send a message with subject or body 'help' to > colorsync-users-request(a)lists.apple.com > > You can reach the person managing the list at > colorsync-users-owner(a)lists.apple.com > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of colorsync-users digest..." > > > Today's Topics: > > 1. Re: Normalizing CIEXYZ Values (WAYNE BRETL) > 2. Re: Normalizing CIEXYZ Values (Jeff Nova) > 3. FW: Normalizing CIEXYZ Values (waynebretl(a)cox.net) > 4. Re: Normalizing CIEXYZ Values (Jeff Nova) > 5. Re: Normalizing CIEXYZ Values (Graeme Gill) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 05 Nov 2022 12:41:59 -0700 (MST) > From: WAYNE BRETL <waynebretl(a)cox.net> > To: Jeff Nova <jnova(a)colorhythm.com>, Jeff Nova via colorsync-users > <colorsync-users(a)lists.apple.com> > Subject: Re: Normalizing CIEXYZ Values > Message-ID: <504420040.889153.1667677320100(a)myemail.cox.net> > Content-Type: text/plain; charset=UTF-8 > > "normalizing to [0,1] first" does not make sense to me. > When you calculate the (lower case) x,y for the chromaticity plot, the > values are automatically between 0 and 1. > > x = (X)/(X+Y+Z) > y = (Y)/(X+Y+Z) > > > On November 5, 2022 at 11:46 AM Jeff Nova via colorsync-users < > colorsync-users(a)lists.apple.com> wrote: > > > > > > Hello my colorful friends! I pray you are doing well. > > > > I have a math question for you. I would like to display the viewing > > conditions' illuminant and surround on a 1931 2deg chromaticity plot. > > These are un-normalized CIEXYZ values that need to be normalized within > the > > plot range (0-1 both axes) first. > > > > Example: > > > > sRGB IEC 2.1 profile: > > > > Illuminant - 19.6445 20.3718 16.8089 > > > > Surround - 3.92889 4.07439 3.36179 > > > > How to normalize them? Please forgive my ignorance; I am learning every > > day. > > > > I thank you in advance for any support you might be able to provide. : ) > > > > Jeff > > > > > > Jeff Nova > > Chief Executive Officer > > > > Colorhythm > > https://colorhythm.com > > Mobile: +1 510-710-9590 > > Main: +1 415-399-9921 > > _______________________________________________ > > Do not post admin requests to the list. They will be ignored. > > colorsync-users mailing list (colorsync-users(a)lists.apple.com) > > Help/Unsubscribe/Update your Subscription: > > > https://lists.apple.com/mailman/options/colorsync-users/waynebretl%40cox.net > > > > This email sent to waynebretl(a)cox.net > > > ------------------------------ > > Message: 2 > Date: Sat, 5 Nov 2022 14:17:36 -0700 > From: Jeff Nova <jnova(a)colorhythm.com> > To: WAYNE BRETL <waynebretl(a)cox.net> > Cc: Jeff Nova via colorsync-users <colorsync-users(a)lists.apple.com> > Subject: Re: Normalizing CIEXYZ Values > Message-ID: <6EB342ED-0FC3-478C-9601-CF45DAE36563(a)colorhythm.com> > Content-Type: text/plain; charset=utf-8 > > Hi Wayne! > > Thank you for sharing your insight. I suppose I am trying to understand > the ICC spec when it presents XYZ values ?un-normalized? vs ?normalized.? > Putting aside the xy conversion ? or is this what is meant? I?ll need to > look at the spec again (and again and again?). > > Jeff > > > On Nov 5, 2022, at 12:42 PM, WAYNE BRETL <waynebretl(a)cox.net> wrote: > > > > ?"normalizing to [0,1] first" does not make sense to me. > > When you calculate the (lower case) x,y for the chromaticity plot, the > values are automatically between 0 and 1. > > > > x = (X)/(X+Y+Z) > > y = (Y)/(X+Y+Z) > > > >> On November 5, 2022 at 11:46 AM Jeff Nova via colorsync-users < > colorsync-users(a)lists.apple.com> wrote: > >> > >> > >> Hello my colorful friends! I pray you are doing well. > >> > >> I have a math question for you. I would like to display the viewing > >> conditions' illuminant and surround on a 1931 2deg chromaticity plot. > >> These are un-normalized CIEXYZ values that need to be normalized within > the > >> plot range (0-1 both axes) first. > >> > >> Example: > >> > >> sRGB IEC 2.1 profile: > >> > >> Illuminant - 19.6445 20.3718 16.8089 > >> > >> Surround - 3.92889 4.07439 3.36179 > >> > >> How to normalize them? Please forgive my ignorance; I am learning every > >> day. > >> > >> I thank you in advance for any support you might be able to provide. : > ) > >> > >> Jeff > >> > >> > >> Jeff Nova > >> Chief Executive Officer > >> > >> Colorhythm > >> https://colorhythm.com > >> Mobile: +1 510-710-9590 > >> Main: +1 415-399-9921 > >> _______________________________________________ > >> Do not post admin requests to the list. They will be ignored. > >> colorsync-users mailing list (colorsync-users(a)lists.apple.com) > >> Help/Unsubscribe/Update your Subscription: > >> > https://lists.apple.com/mailman/options/colorsync-users/waynebretl%40cox.net > >> > >> This email sent to waynebretl(a)cox.net > > > ------------------------------ > > Message: 3 > Date: Sat, 05 Nov 2022 14:33:16 -0700 > From: waynebretl(a)cox.net > To: colorsync-users(a)lists.apple.com > Subject: FW: Normalizing CIEXYZ Values > Message-ID: <005101d8f15e$38e1eda0$aaa5c8e0$(a)cox.net> > Content-Type: text/plain; charset=UTF-8 > > > > -----Original Message----- > From: waynebretl(a)cox.net <waynebretl(a)cox.net> > Sent: Saturday, November 5, 2022 2:29 PM > To: 'Jeff Nova' <jnova(a)colorhythm.com> > Subject: RE: Normalizing CIEXYZ Values > > If you are trying to do a chromatic adaptation transform, I will let > someone else answer, as I would probably get it wrong somewhere. > > Here's a Wikipedia intro: > > https://en.wikipedia.org/wiki/Chromatic_adaptation#CIE_color_appearance_mod… > > -----Original Message----- > From: Jeff Nova <jnova(a)colorhythm.com> > Sent: Saturday, November 5, 2022 2:18 PM > To: WAYNE BRETL <waynebretl(a)cox.net> > Cc: Jeff Nova via colorsync-users <colorsync-users(a)lists.apple.com> > Subject: Re: Normalizing CIEXYZ Values > > Hi Wayne! > > Thank you for sharing your insight. I suppose I am trying to understand > the ICC spec when it presents XYZ values ?un-normalized? vs ?normalized.? > Putting aside the xy conversion ? or is this what is meant? I?ll need to > look at the spec again (and again and again?). > > Jeff > > > On Nov 5, 2022, at 12:42 PM, WAYNE BRETL <waynebretl(a)cox.net> wrote: > > > > ?"normalizing to [0,1] first" does not make sense to me. > > When you calculate the (lower case) x,y for the chromaticity plot, the > values are automatically between 0 and 1. > > > > x = (X)/(X+Y+Z) > > y = (Y)/(X+Y+Z) > > > >> On November 5, 2022 at 11:46 AM Jeff Nova via colorsync-users < > colorsync-users(a)lists.apple.com> wrote: > >> > >> > >> Hello my colorful friends! I pray you are doing well. > >> > >> I have a math question for you. I would like to display the viewing > >> conditions' illuminant and surround on a 1931 2deg chromaticity plot. > >> These are un-normalized CIEXYZ values that need to be normalized > >> within the plot range (0-1 both axes) first. > >> > >> Example: > >> > >> sRGB IEC 2.1 profile: > >> > >> Illuminant - 19.6445 20.3718 16.8089 > >> > >> Surround - 3.92889 4.07439 3.36179 > >> > >> How to normalize them? Please forgive my ignorance; I am learning > >> every day. > >> > >> I thank you in advance for any support you might be able to provide. > >> : ) > >> > >> Jeff > >> > >> > >> Jeff Nova > >> Chief Executive Officer > >> > >> Colorhythm > >> https://colorhythm.com > >> Mobile: +1 510-710-9590 > >> Main: +1 415-399-9921 > >> _______________________________________________ > >> Do not post admin requests to the list. They will be ignored. > >> colorsync-users mailing list (colorsync-users(a)lists.apple.com) > >> Help/Unsubscribe/Update your Subscription: > >> https://lists.apple.com/mailman/options/colorsync-users/waynebretl%40 > >> cox.net > >> > >> This email sent to waynebretl(a)cox.net > > > > ------------------------------ > > Message: 4 > Date: Sat, 5 Nov 2022 20:28:26 -0700 > From: Jeff Nova <jnova(a)colorhythm.com> > To: WAYNE BRETL <waynebretl(a)cox.net> > Cc: Jeff Nova via colorsync-users <colorsync-users(a)lists.apple.com> > Subject: Re: Normalizing CIEXYZ Values > Message-ID: > < > CAPTwpmZMsbSCv4WJpNO3G+_x8LENv5zHx+Rj_0oXDShCxwOxBQ(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Regarding the larger question... > > Inside an ICC profile, for example, the PCS illuminant if XYZ is formatted > as such: > > XYZ 0.9642 1 0.82491 > > while as I shared, the illuminant of viewing condition is like the > example,19.6445 20.3718 16.8089 > > I would think that the first example has been normalized with the largest > number = 1? > > - Jeff > > > > > Jeff Nova > Chief Executive Officer > > Colorhythm > https://colorhythm.com > Mobile: +1 510-710-9590 > Main: +1 415-399-9921 > > > On Sat, Nov 5, 2022 at 12:42 PM WAYNE BRETL <waynebretl(a)cox.net> wrote: > > > "normalizing to [0,1] first" does not make sense to me. > > When you calculate the (lower case) x,y for the chromaticity plot, the > > values are automatically between 0 and 1. > > > > x = (X)/(X+Y+Z) > > y = (Y)/(X+Y+Z) > > > > > On November 5, 2022 at 11:46 AM Jeff Nova via colorsync-users < > > colorsync-users(a)lists.apple.com> wrote: > > > > > > > > > Hello my colorful friends! I pray you are doing well. > > > > > > I have a math question for you. I would like to display the viewing > > > conditions' illuminant and surround on a 1931 2deg chromaticity plot. > > > These are un-normalized CIEXYZ values that need to be normalized within > > the > > > plot range (0-1 both axes) first. > > > > > > Example: > > > > > > sRGB IEC 2.1 profile: > > > > > > Illuminant - 19.6445 20.3718 16.8089 > > > > > > Surround - 3.92889 4.07439 3.36179 > > > > > > How to normalize them? Please forgive my ignorance; I am learning > every > > > day. > > > > > > I thank you in advance for any support you might be able to provide. > : ) > > > > > > Jeff > > > > > > > > > Jeff Nova > > > Chief Executive Officer > > > > > > Colorhythm > > > https://colorhythm.com > > > Mobile: +1 510-710-9590 > > > Main: +1 415-399-9921 > > > _______________________________________________ > > > Do not post admin requests to the list. They will be ignored. > > > colorsync-users mailing list (colorsync-users(a)lists.apple.com) > > > Help/Unsubscribe/Update your Subscription: > > > > > > https://lists.apple.com/mailman/options/colorsync-users/waynebretl%40cox.net > > > > > > This email sent to waynebretl(a)cox.net > > > > > ------------------------------ > > Message: 5 > Date: Sun, 06 Nov 2022 17:54:32 +1100 > From: Graeme Gill <graeme2(a)argyllcms.com> > To: ColorSync <colorsync-users(a)lists.apple.com> > Subject: Re: Normalizing CIEXYZ Values > Message-ID: <e0351c87-e903-3273-c0f6-9bc6b7414143(a)argyllcms.com> > Content-Type: text/plain; charset=UTF-8; format=flowed > > Jeff Nova via colorsync-users wrote: > > > I have a math question for you. I would like to display the viewing > > conditions' illuminant and surround on a 1931 2deg chromaticity plot. > > These are un-normalized CIEXYZ values that need to be normalized within > the > > plot range (0-1 both axes) first. > > > > Example: > > > > sRGB IEC 2.1 profile: > > > > Illuminant - 19.6445 20.3718 16.8089 > > > > Surround - 3.92889 4.07439 3.36179 > > > > How to normalize them? Please forgive my ignorance; I am learning every > > day. > > Hello Jeff, > when dealing with reflective or transmissive media, it > is usual to relate measurements to 100% reflectance or transmittance > of the light source. Typically the instrument does this for you - > it measures the reflected/transmitted spectrum then divides by the > actual instrument 100% illuminant spectrum, then computes the resultant XYZ > by integrating over an (by ICC convention) D50 light source. > That light source XYZ value will have a Y value of 1.0 or 100%, meaning > that the measured values will also cover this range. > > Within the ICC profile itself reflectance or transmittance XYZ values have > a nominal range > of 0..1, although it is convention in other file formats (such as CGATS) > to use a % range > of 0..100. Some measurements might exceed 100% due to fluorescence etc. > > Viewing conditions will typically remain in absolute XYZ terms so as to > convey > the absolute light level, but if only the chromaticity is of interest, you > could > divide the XYZ by the Y value. > > As noted by Wayne Bretl, xy chromaticity values don't typically require > this normalization since it is taken care of by the very nature of the > calculation. > > Cheers, > Graeme Gill. > > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > colorsync-users mailing list > colorsync-users(a)lists.apple.com > https://lists.apple.com/mailman/listinfo/colorsync-users > > > ------------------------------ > > End of colorsync-users Digest, Vol 19, Issue 45 > *********************************************** >

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[NEXT MONTH] Don't Miss Color and Imaging Tech at its Best~CIC30
by Roberta Morehouse 08 Nov '22

08 Nov '22

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Normalizing CIEXYZ Values
by Jeff Nova 06 Nov '22

06 Nov '22

Hello my colorful friends! I pray you are doing well. I have a math question for you. I would like to display the viewing conditions' illuminant and surround on a 1931 2deg chromaticity plot. These are un-normalized CIEXYZ values that need to be normalized within the plot range (0-1 both axes) first. Example: sRGB IEC 2.1 profile: Illuminant - 19.6445 20.3718 16.8089 Surround - 3.92889 4.07439 3.36179 How to normalize them? Please forgive my ignorance; I am learning every day. I thank you in advance for any support you might be able to provide. : ) Jeff Jeff Nova Chief Executive Officer Colorhythm https://colorhythm.com Mobile: +1 510-710-9590 Main: +1 415-399-9921

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