May 2013 - colorsync-users - lists.apple.com

B+W 77mm UV/IR Cut (486M) MRC Filter
by Millers' Photography L.L.C. 27 May '13

27 May '13

I must thank someone on this list that suggested purchasing the B+W 77mm UV/IR Cut (486M) MRC Filter for issues I had with reproducing a particular piece of original art. It was around June 15, 2012. I purchased a B+W 67mm UV/IR Cut (486M) MRC Filter as well. These filters are always on the shooting lens. I don't remember who it was. I have been asked who it was. If you are out there, please respond. Warm Regards, David David B Miller, Pharm. D. member Millers' Photography L.L.C. dba Spinnaker Photo Imaging Center Bellingham, WA www.spinnakerphotoimagingcenter.com 360 739 2826

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Re: B+W 77mm UV/IR Cut (486M) MRC Filter
by John Castronovo 26 May '13

26 May '13

True enough about the age of the article, but I didn't think that sensor filtration changed that much. It would be nice and I stand corrected if that's the case, but I think that sensors are still very sensitive to IR unless filtered and good IR filters aren't transparent. I think that losing of an extra stop or more of sensitivity to cure IR problems that only show up with certain problematic copy work is something camera manufacturers aren't likely to do. -----Original Message----- From: Iliah Borg Sent: Sunday, May 26, 2013 12:36 PM To: John Castronovo Subject: Re: B+W 77mm UV/IR Cut (486M) MRC Filter Dear John, > Robin Meyers did some experiments for Betterlight and wrote a great paper > describing this issue of IR in digitally reproducing problematic fine art: > http://www.betterlight.com/downloads/whitePaper/wp_color_accurate_photo.pdf > This article is from 2000. We now at the rate of about 1 new camera with raw capabilities per week. The filtration on the sensors and the sensor itself changed dramatically. -- Best regards, Iliah Borg ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3343 / Virus Database: 3184/6359 - Release Date: 05/26/13

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Re: B+W 77mm UV/IR Cut (486M) MRC Filter
by John Castronovo 26 May '13

26 May '13

I agree with your comment about needing to decide whether or not we actually want art to fluoresce for the camera, but when white is brighter than white and also brighter than anything in my profile target, I think it could be a source for more problems down the road, so I'd rather filter the UV at the light source. It's not exactly a lie to view and copy the original in light that has less rather than more UV either, so I feel that it's a variable we don't need at the camera. However to meet the new ISO standards in 2009, viewing boxes and luminaries for critical viewing such as those made by GTI went from allowing none to now allowing a controlled amount of UV. http://info.gtilite.com/2011/01/where-do-you-set-your-standards/#.UaI2NZw_B… I've seen this specification go from a lot to none to now some UV over the years so even the experts who write the standards don't always agree how things should look, so I decide in my shop what's best for my copy processes. I know one thing, my calibrated display only goes to white, not brighter than white, and I print on papers that don't have OBAs in them either so I think it's best to filter it out at the light source. Robin Meyers did some experiments for Betterlight and wrote a great paper describing this issue of IR in digitally reproducing problematic fine art: http://www.betterlight.com/downloads/whitePaper/wp_color_accurate_photo.pdf -----Original Message----- From: Iliah Borg Sent: Sunday, May 26, 2013 11:45 AM To: John Castronovo Subject: Re: B+W 77mm UV/IR Cut (486M) MRC Filter On May 26, 2013, at 11:39 AM, John Castronovo wrote: > It's still best to keep UV from exciting the artwork to fluoresce in the > visible spectrum The question is - what is it that we are trying to reproduce? If the original fluorescents, and the eye can see it,..? Other than that, the UV is to be filtered off on the light sources. > The most infamous case of IR issues with art comes from cobalt blue > pigment which will turn purple on digital capture. It's common to need > additional IR filtration at the camera As I said, maybe to test the camera before mounting those additional glass-air interfaces which add flare. -- Best regards, Iliah Borg ----- No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.3343 / Virus Database: 3184/6359 - Release Date: 05/26/13

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white reference for spectro - what are the effects of a change?
by edmund ronald 25 May '13

25 May '13

My new white ref is roughly 3de from the old, and looks yellowish. What are going to be the effects? Can one write a script to mod the spectral data to take this into account? I can use another device to measure some stuff. Edmund

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Re: Colorsync-users Digest, Vol 10, Issue 102
by Peter A. Calvin 24 May '13

24 May '13

Marvelous. Peter Calvin Sent from my iPhone On May 24, 2013, at 2:00 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. Courses and training - need suggestions or recommendations. > (Joseph Chamberlain) > 2. Re: Courses and training - need suggestions or > recommendations. (Steve Miller) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 24 May 2013 08:04:34 -0700 > From: Joseph Chamberlain <drjchamberlain(a)gmail.com> > To: colorsync-users(a)lists.apple.com > Subject: Courses and training - need suggestions or recommendations. > Message-ID: <F29B4C03-463A-4A52-AB44-FAA8382B1790(a)gmail.com> > Content-Type: text/plain; charset=us-ascii > > Hi, Everyone. > > I would like to either read a book or attend a course (short, half to one full day in duration) as a primer on color technology. The subjects I would like to learn more about are different color models and color spaces, different gamut between devices (monitors x printers), calibration of computer monitors for proper color reproduction and how it is performed including the use of LUT (look up tables), lighting for proper viewing and color evaluation, and others. > > Is there a book on color technology that would cover all these topics for those like with only basic knowledge of color technology and digital devices? In case there isn't are there any courses any of you could recommend that would address these topics? > > Thank you in advance, > > Joseph. > > ------------------------------ > > Message: 2 > Date: Fri, 24 May 2013 10:45:45 -0500 > From: Steve Miller <SLMiller(a)norwood.com> > To: Joseph Chamberlain <drjchamberlain(a)gmail.com>, > "colorsync-users(a)lists.apple.com" <colorsync-users(a)lists.apple.com> > Subject: Re: Courses and training - need suggestions or > recommendations. > Message-ID: <CDC4F4D8.31AF%SLMiller(a)norwood.com> > Content-Type: text/plain; charset=us-ascii > > This book will help. > Real World Color Management (2nd Edition) [Paperback] > > For training, you could look to Idealliance. They have online courses. > http://www.idealliance.org/store/color-management-professional-courses > > > > -- > > Steve Miller > Color Management Specialist > > "Quality Begins Here" > > BIC Advertising & Promotional Products > 1000 3rd Ave. SW > Sleepy Eye, MN 56085 > > Tel.: (1) 507 794 8203 > E-mail: slmiller(a)norwood.com > www.norwood.com / www.bicgraphic.com > > > CONFIDENTIALITY NOTICE > This electronic message is confidential and may contain legally privileged > information intended only for the use of the individual or company named > above. If the reader of this message is not the intended recipient, or the > employee or agent responsible to deliver it to the intended recipient, you > are hereby notified that any dissemination, distribution or copying of > this communications is strictly prohibited. If you have received this > communication in error please immediately notify us by telephone, and > return the original message to us at the address below. > IRS Circular 230 Disclosure: As provided for in Treasury regulations, > advice (if any) relating to federal taxes that is contained in this > communication (including attachments) is not intended or written to be > used, and cannot be used, for the purpose of (1) avoiding penalties under > the IRS Code or (2) promotion, marketing or recommending to another party > any transaction or matter addressed herein: Norwood & BIC Graphic, 14421 > Myerlake Circle, Clearwater, FL 33760. www.norwood.com / www.bicgraphic.com > > > > On 24/05/2013 10:04, "Joseph Chamberlain" <drjchamberlain(a)gmail.com> wrote: > >> Hi, Everyone. >> >> I would like to either read a book or attend a course (short, half to one >> full day in duration) as a primer on color technology. The subjects I >> would like to learn more about are different color models and color >> spaces, different gamut between devices (monitors x printers), >> calibration of computer monitors for proper color reproduction and how it >> is performed including the use of LUT (look up tables), lighting for >> proper viewing and color evaluation, and others. >> >> Is there a book on color technology that would cover all these topics for >> those like with only basic knowledge of color technology and digital >> devices? In case there isn't are there any courses any of you could >> recommend that would address these topics? >> >> Thank you in advance, >> >> Joseph. >> _______________________________________________ >> 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/slmiller%40norwood >> .com >> >> This email sent to slmiller(a)norwood.com > > > > > ------------------------------ > > _______________________________________________ > Colorsync-users mailing list > Colorsync-users(a)lists.apple.com > https://lists.apple.com/mailman/listinfo/colorsync-users > > End of Colorsync-users Digest, Vol 10, Issue 102 > ************************************************

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Re: Primer on photographic exposure, etc.
by Alex Jamison 22 May '13

22 May '13

Hello Ben, Thank you for the intriguing article. You lost me at this point: "After you’ve physically assembled it, you then need to read each of the patch values, one by one, with a spectrophotometer. You then need to put those values together in the proper chart recognition files." How would a camera input profile be made from a custom chart that could be used in raw processing software other than RPP? Thank you, Alex Jamison > > > Message: 1 > Date: Mon, 13 May 2013 21:29:18 -0700 > From: Ben Goren <ben(a)trumpetpower.com> > To: undisclosed-recipients: ; > Subject: Primer on photographic exposure, etc. > Message-ID: <781E8116-B56D-41AF-B7AE-D3E2A6841518(a)trumpetpower.com> > Content-Type: text/plain; charset=us-ascii > > Here: > > https://trumpetpower.com/photos/Exposure > > is a first attempt at a document I've been meaning to write for a while. I'm afraid I don't have the time right now to further put into refining it; it's much too long and ideally needs to be broken apart and probably have different parts re-written multiple times tailored for different audiences -- and I *really* don't have the time for that sort of thing. > > But, still, I hope it answers many of the questions I've had asked of me of late > > Cheers, > > b&

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Re: Primer on photographic exposure, etc.
by Iliah Borg 17 May '13

17 May '13

Dear Wayne, Can you please describe how you got raw data from cameras, and how the data is normalised? What procedure was used while taking the shots? What lens was used on the camera, and what are the spectral properties of the lens? -- Best regards, Iliah Borg

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RE: Primer on photographic exposure, etc.
by Lars Borg 16 May '13

16 May '13

Hello Wayne, Your presentation that I attended at SMPTE was excellent! A must-see for any camera calibrator. Do you have plans for further presentations? Lars At 6:42 PM -0700 5/15/13, Wayne Bretl wrote: >When you get the best match to reflective test patches, you normally will >get some spectral colors outside the spectral locus and some inside. On the >other hand, fitting a selection of spectral colors to the spectral locus >does not necessarily give the best possible match to reflective patches, >which have broader spectra. > >This comes about due to the mismatch of the camera spectral responses to >eyeball responses. Most camera responses are narrower than eyeball cone >responses, so as scene spectra become narrower (colors become more >saturated) the camera response saturates (one or two channels goes to zero >or an abnormally low value) before a spectral color of complete purity is >reached. At some point before a pure single wavelength is reached, the >camera stops indicating an increase in saturation. At this point, no further >adjustment by lookup table or any other means can help. If the reflective >patches with high (but not 100%) saturation are to be reproduced accurately, >pure spectral colors must be sacrificed, because the camera cannot see the >difference between high saturation and 100% saturation. > >This is explained in the paper I gave at the 2011 SMPTE conference, which >was published in the May-June 2012 issue of the Journal. The abstract is >here: >http://journal.smpte.org/content/121/4/69.abstract > >I have attached the slide presentation, which illustrates the effects of >real camera responses of various types, and particularly has some >illustrations of the effects of a series of spectra with progressively >narrower width, so you can see the response of these cameras to highly >saturated colors and spectral colors when they have been matrixed for the >best fit to the 24 patch chart. Of course, using more patches will give >somewhat different results, but the saturation compression will still be >present. Once the compression becomes severe, it is impractical to spread >these colors apart by application of a profile of any kind. > >This effect is especially severe with typical film responses, less so with >the wider, more overlapping responses typical of DSLRs. > >I'd also note that both surface colors and reproduced colors are typically >limited in saturation in the cyan area, so attempting to match spectral >colors in this range is mostly futile as well as not needed. My presentation >says a few things about this too. > >-Wayne Bretl > >-----Original Message----- >From: colorsync-users-bounces+waynebretl=comcast.net(a)lists.apple.com >[mailto:colorsync-users-bounces+waynebretl=comcast.net@lists.apple.com] On >Behalf Of Lars Borg >Sent: Wednesday, May 15, 2013 5:20 PM >To: Iliah Borg >Cc: colorsync-users(a)lists.apple.com >Subject: Re: Primer on photographic exposure, etc. > >Still, with such a target you're calibrating only for reflective colors. >Shouldn't you include more colors near the spectrum locus? >Don't you get a lot of on-spectrum-locus colors ending up outside the >spectrum locus? >(A common problem with camera calibration) > >On a separate issue: >Sure there are target tolerances for the same SKU. >(And camera tolerances for any given camera model) Do you have actual dE >numbers? >Are these tolerances bigger than the color inaccuracy of the camera system >itself (which is maybe 10 dE over a large set of colors after calibration)? > >I'm curious, as AMPAS has similar issues with camera calibration. > >BTW, any experience with the Image Engineering camSPECS? > >Lars B > >At 11:05 AM -0700 5/15/13, Iliah Borg wrote: >>Dear Ben, >> >>I'm just saying that C1 prefers LUT profiles, and there are 2 ways of >>doing it - make a matrix and convert to LUT; or make LUT directly. One >>can do both and keep both, they both have their own advantages. > > >>For a minimal profile 24 patches is too little with current profiling >>engines, matrix or LUT, does not matter. ColorCheckerSG with its 140 >>patches is a far better choice. Making a combined target from 3 shots >>of SG bracketing the exposure by 2 stops is even better. Target needs >>to be individually and accurately measured, canned measurements do not >>fit well. Scaling for a combined 420-patch (140*3) target is easier if >>measurements are spectral. > _______________________________________________ >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%40comcast >.net > >This email sent to waynebretl(a)comcast.net > >Content-Type: >application/vnd.openxmlformats-officedocument.presentationml.slideshow; > name="1569465737 Theoretical and Practical Limits to Wide >Color Gamut r3.ppsx" >Content-Description: 1569465737 Theoretical and Practical Limits to Wide > Color Gamut r3.ppsx >Content-Disposition: attachment; filename="1569465737 Theoretical >and Practical Limits to Wide Color Gamut r3.ppsx"; size=2558128; > creation-date="Thu, 16 May 2013 01:42:51 GMT"; > modification-date="Thu, 16 May 2013 01:42:51 GMT" > >Attachment converted: LarsDeskMac12:1569465737 Theoret#199C463.ppsx >( / ) (0199C463)

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Comments on Ben's essay
by Brian Lawler 14 May '13

14 May '13

Greetings, I congratulate Ben for his excellent essay on exposure (and much more). It's delightful and insightful. Two very small comments: 1. Raw is just a word, not an acronym, so should be spelled as Raw, not RAW (shouting). I usually use "Camera Raw" instead of just "Raw" so it is more explanatory. 2. The word "helpfully" is spelled with just one l in the document. I enjoyed the essay immensely, and plan to read it in depth this evening. Thank you, Ben, for sharing it with us. Best wishes, Brian P. Lawler Brian P. Lawler Associate Professor Graphic Communication Department California Polytechnic State University San Luis Obispo, California 93407-0381 Tel: 805 756-1107 Fax: 805 756-7118 E-Mail: blawler(a)calpoly.edu Web: www.thelawlers.com A teacher affects eternity; he can never tell where his influence stops. – Henry B. Adams

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Primer on photographic exposure, etc.
by Ben Goren 14 May '13

14 May '13

A couple people have pointed out that the link below is to the https (secure) server on my site, which is something I did without paying much attention to. Since I use a self-signed SSL certificate, many browsers ``helpfully'' warn that there's no way of knowing that I am who I say I am. You can access the exact same document without the warnings here: http://trumpetpower.com/photos/Exposure b& Original message follows: Here: https://trumpetpower.com/photos/Exposure is a first attempt at a document I've been meaning to write for a while. I'm afraid I don't have the time right now to further put into refining it; it's much too long and ideally needs to be broken apart and probably have different parts re-written multiple times tailored for different audiences -- and I *really* don't have the time for that sort of thing. But, still, I hope it answers many of the questions I've had asked of me of late Cheers, b&

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