May 2020 - colorsync-users - lists.apple.com

RE: Lab -> RGB
by graxx＠videotron.ca 07 May '20

07 May '20

It's a jungle out there. / Roger -----Original Message----- From: Henry Davis via colorsync-users <colorsync-users(a)lists.apple.com> Sent: Wednesday, May 6, 2020 10:01 PM To: 'colorsync-users?lists.apple.com' List <colorsync-users(a)lists.apple.com> Subject: Re: Lab -> RGB IF.?. Sounds like assumptions are still big in play. Henry Davis > On May 6, 2020, at 9:09 PM, Andrew Rodney via colorsync-users <colorsync-users(a)lists.apple.com> wrote: > > IF everything is color managed, Adobe RGB (1998) is fine. If it isn’t color managed, it will still look reasonably good on a wide gamut display, awful on an sRGB gamut display. The opposite is seen with sRGB (OK on sRGB gamut display, not on wide gamut display). > So if again, everything is color managed (the image data and browser) AND your audience is using wide gamut displays, you gain nothing with sRGB and a bit wider gamut from the original in Adobe RGB (1998). Or DCI-P3 (6 of one, half dozen of the other). > > Andrew Rodney > http://www.digitaldog.net/ _______________________________________________ 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/graxx%40videotron.ca This email sent to graxx(a)videotron.ca

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RE: Lab -> RGB
by graxx＠videotron.ca 07 May '20

07 May '20

Endless discussion, Jeff. Believe me. One way or another, the “web appearance” will never match what you see on your monitor. Are you looking at “AdobeRGB” versions of your images on your monitor? In Photoshop? That ought to be the starting point, IMO, if you want to go that route. And then look at your images on anyone else’s monitors/tablets. / Roger From: Jeff Nova <jnova(a)colorhythm.com> Sent: Wednesday, May 6, 2020 8:59 PM To: graxx(a)videotron.ca Cc: 'colorsync-users?lists.apple.com' List <colorsync-users(a)lists.apple.com> Subject: Re: Lab -> RGB My userbase commonly has full Adobe RGB coverage monitors - creative professionals. So maybe that’s the choice? - J > On May 6, 2020, at 5:55 PM, graxx(a)videotron.ca <mailto:graxx@videotron.ca> wrote: > > I don't see how you could go wrong with sRGB, ntil the day more people are looking at the web through wide gamut displays, be it tablets or monitors. > > My two cents, > > Roger Breton > www.graxx.ca <http://www.graxx.ca> > > -----Original Message----- > From: Jeff Nova via colorsync-users <colorsync-users(a)lists.apple.com <mailto:colorsync-users@lists.apple.com> > > Sent: Wednesday, May 6, 2020 8:01 PM > To: colorsync-users(a)lists.apple.com <mailto:colorsync-users@lists.apple.com> > Subject: Lab -> RGB > > Hi friends, > > > We have a web application and want to display the best previews we can for Lab images, which are not supported by any browser. The Lab we expect is the default Lab from Photoshop, which I think is D50. So, what is the best choice for RGB space? We are tagging the files, and prefer v2 profiles for more browser compatibility, but will do v4 is needed. I don't need help in the transformation - I just want to know the best RGB space to present the widest gamut resembling Lab as possible. > > > I assume one of the best choices is Don's MaxRGB? > > > http://www.hutchcolor.com/profiles.html > > > I welcome any input! > > > Very best, > Jeff > > > -- > Jeff NovaChief Executive OfficerColorhythm > jnova(a)colorhythm.comMain <mailto:jnova@colorhythm.comMain> : +1 415-399-9921Direct: +1 415-399-9921 x407Mobile: +1 510-710-9590Fax: +1 415-399-9928 > > 1015 Battery Street, Suite CSan Francisco CA 94111http://colorhythm.com > > Please consider our environmentbefore printing this email Colorhythm is a certified Green Business: > > This electronic mail and the documents accompanying it are considered trade secret, confidential and/or proprietary by Colorhythm LLC. This information is intended for use by the individual or entity to whom this e-mail is addressed. If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this information is prohibited. > -- Jeff Nova Chief Executive Officer Colorhythm jnova(a)colorhythm.com <mailto:jnova@colorhythm.com> Main: +1 415-399-9921 Direct: +1 415-399-9921 x407 Mobile: +1 510-710-9590 Fax: +1 415-399-9928 1015 Battery Street, Suite C San Francisco CA 94111 http://colorhythm.com Please consider our environment before printing this email Colorhythm is a certified Green Business: This electronic mail and the documents accompanying it are considered trade secret, confidential and/or proprietary by Colorhythm LLC. This information is intended for use by the individual or entity to whom this e-mail is addressed. If you are not the intended recipient, be aware that any disclosure, copying, distribution or use of the contents of this information is prohibited.

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Re: CxF format
by Robin Myers 04 May '20

04 May '20

Hello Mr. Breton, If you were to look near the end of the ColorChecker.cxf file provided by X-Rite, you would find the MeasurementSpec block of XML (highlighted in blue below). Inside this block is the DeviceIllumination (highlighted in red below), which is what you are looking for. <ColorSpecificationCollection> <ColorSpecification Id="CSD50-2"> <TristimulusSpec> <Illuminant>D50</Illuminant> <Observer>2_Degree</Observer> <Method>E308_Table5</Method> </TristimulusSpec> <MeasurementSpec> <MeasurementType>Colorimetric_Reflectance</MeasurementType> <GeometryChoice> <SingleAngle> <SingleAngleConfiguration>Annular</SingleAngleConfiguration> <IlluminationAngle>45.0</IlluminationAngle> <MeasurementAngle>0.0</MeasurementAngle> </SingleAngle> </GeometryChoice> </MeasurementSpec> </ColorSpecification> <ColorSpecification Id="CSD65-2"> <TristimulusSpec> <Illuminant>D65</Illuminant> <Observer>10_Degree</Observer> <Method>E308_Table6</Method> </TristimulusSpec> <MeasurementSpec> <MeasurementType>Spectrum_Reflectance</MeasurementType> <GeometryChoice> <SingleAngle> <SingleAngleConfiguration>Annular</SingleAngleConfiguration> <IlluminationAngle>45.0</IlluminationAngle> <MeasurementAngle>0.0</MeasurementAngle> </SingleAngle> </GeometryChoice> <WavelengthRange StartWL="400" Increment="10"/> <CalibrationStandard>Ceramic</CalibrationStandard> <Device> <Manufacturer>XRite</Manufacturer> <Model>XR962</Model> <SerialNumber/> <DeviceClass>DeviceClass_Spot</DeviceClass> <DeviceFilter>Filter_None</DeviceFilter> <DeviceIllumination>M0_Incandescent</DeviceIllumination> <DevicePolarization>false</DevicePolarization> </Device> </MeasurementSpec> </ColorSpecification> </ColorSpecificationCollection> Regards, Robin Myers

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CxF format
by graxx＠videotron.ca 04 May '20

04 May '20

Good morning everyone, I'm doing a study on CxF format. I'm stuck on the "Color Specification" section. I'm looking for a fail proof method of determining whether the data in a CxF file, such as PANTONE colors, is in "M0" or "M1" or "M2" or "M3" format? I realize there could be a mix of these but it's not clear-cut how this important specification is to be handled; they don't have a friendly "normative" section in CxF_Standard_en.pdf (from X-Rite). It's probably an ISO standard by now? Any help is appreciated. I'll gladly take sample CxF files. / Roger Breton www.graxx.ca

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