September 2015 - colorsync-users

Re: Colorsync-users Digest, Vol 12, Issue 114
by Millers' Photography L.L.C. 18 Sep '15

18 Sep '15

Jon, please describe in detail your method written below…….(1/5 exposure) and cross polarized (4/5) > On Sep 18, 2015, at 12:00 PM, colorsync-users-request(a)lists.apple.com wrote: > > In addition to the previously stated, my 4x5 fine art repro days included a blend of specular directional (1/5 exposure) and cross polarized (4/5). This captured better brush stroke textures. > Jon David B. Miller, Pharm. D. 3809 Alabama Street Bellingham, Washington, 98226-4585 360 739 2826

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More on fine art reproduction
by Brian Lawler 18 Sep '15

18 Sep '15

Hi everyone, Regarding Louis Dina’s post about reproducing the oil paintings… I have tried to do this using Alien Bees strobes, and eventually gave up in frustration. I use a very methodical technique for doing fine art photography that includes putting polarizing filters on the lamps, and also putting a polarizer on the lens. Then I make a profile, using the ColorChecker Passport and load that into Photoshop. It all works pretty well. BUT, the Alien Bees lamps do not have a clean enough color-rendering index to photograph fine art successfully. I tried the same set-up with my four Paul C. Buff Einstein lamps, and that did the trick, mostly. These strobes are much better for fine art, and they got me very, very close. There were still some colors that did not capture correctly. In a conversation I had with our friend Don Hutcheson, he suggested that I could solve the few small color problems I still have by using incandescent lamps. These incandescent lamps use tungsten filaments, and they have a continuous CRI, where almost any strobe lamp, even the Einsteins, will likely have small gaps in the CRI “curve” of the lamp’s output. I have now tried the same set-up with four incandescent lamps, and it works even better. The only problem is the heat. My polarizing filters nearly melt, the room gets very hot, and the room is uncomfortably warm. But I get much better color. Best wishes, Brian P. Lawler

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Re Art Duplication
by joel＠joelmark.com 17 Sep '15

17 Sep '15

Hi Lou, I have photographed paintings for several clients who are painters. To balance color, I place an X-rite Grey Scale Balance Card in the center of the frame, photograph it at my “best” exposure, and use the eye dropper in Lightroom to sample the grey bar to get the color balance. I set the white bar to around 90 and the black bar to about 15. Then, I sync the results to my bracket. I make local adjustments as my client requires. As for glare, etc., I deal with that, when necessary, by processing my bracket as HDR. Joel Joel H. Mark, Photographer (323) 874-9907 www.joelmark.com

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Art Duplication
by Louis Dina 17 Sep '15

17 Sep '15

I want to duplicate some oil paintings on canvas. The surface is reflective, glossy, textured paints, and in places, the dimples of the canvas are visible. The oil paintings are coated with a gloss varnish of some sort. My tools are limited, but they'll have to do. I just want to get as close as I can using the tools I have. First, some background. I'm using a Canon 5Dmk2, 85mm prime lens with circular polarizer, two Alien Bee studio strobes on either side with polarizer gels (cross polarized to eliminate reflections and glare) aimed at 45°angles. I'm photographing the artwork with a small Color Checker and a Spyder Cube (for the light trap) to help me assess tone and color. I built a custom camera profile using XRite Color Checker Passport and I'm processing the images in LightRoom. I know, not perfect. In the past, I had a tough time getting even a lone color checker to reproduce fairly accurately until I forced the 6 neutral patches to match the L* values of my CC target (which I read with my Eye One with UV Cut filter). Once I got the L* values of the 6 neutral patches right, the 18 color patches measured fairly close to my spectro readings. Close enough for me. My conclusion is that the default LR settings are so contrasty, even with a "linear" Tone Curve, that it pumps everything way up and whacks the colors. In LR, I apply my custom camera profile, Click-WB on the 50% gray patch (which is the closest to dead neutral on my CC target), then manually adjust the Tone Curve to match the neutral L* values of my CC to match my spectro readings. My first photos of the artwork had some flare/glare/reflection due to the high gloss shine, so when I got the CC Target looking right, the paintings looked washed out and flat. I assumed this was the reason the CC looked right, but the painting did not. That's when I decided to try polarized light sources and a polarizer on the camera lens. It definitely helped and I am pleased with the improvement. However, even with the polarized images, if I force the L* values of the 6 neutral CC patches to match my spectro readings, the images still look a bit flat and washed out. The CC itself looks great and all the patches measure pretty close. I can adjust the image so it DOES look pretty accurate by eyeball, but then the contrast of the color checker ends up being high. Mainly, I have to darken the darken the black and Dark Gray patches so the painting looks right. I'm hoping to come up with a method that doesn't rely so much on memory and feel. I'm baffled as to why this would be? (unless I still have some flare). Any thoughts or suggestions? (additional equipment or software is not a consideration at this time). Thanks, Lou Dina

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Art Duplication
by Gerry Yaeger 17 Sep '15

17 Sep '15

On Sep 17, 2015, at 12:00 PM, colorsync-users-request(a)lists.apple.com wrote: Quite a few years ago I had a client in L.A. who wanted to make inkjet duplications on canvas of original oil paintings. He was using a leaf digital back on medium format. I could create a profile, spot on of the Color Checker but it was no good for the paintings. The paint pigments were not the same as the Color Checker pigments. No amount of fooling with the light can fix that. He had to get a good prepress guy to tweak the files. Once that was done we could profile the printers close enough to print different sizes on different printers and have a match. We had to run new profile targets before each production run because the bulk inks he was using were not consistent enough from batch to batch. Gerry Yaeger TheDigitalCoach.com

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Re: Colorsync-users Digest, Vol 12, Issue 111
by Neil Steinberg 17 Sep '15

17 Sep '15

Lou, I'm curious as to the size of your paintings. My experience is that, in general, it is difficult to get even coverage and avoid hot spots using only one strobe per side. My setup involves two strobe heads per side which allows for smoother coverage, especially for very large pieces (5' wide and more.) The 45 degree angle is correct, but you should also feather the reflectors outward to smooth the coverage and lower the contrast. Definitely use barn doors or some sort of shield to prevent spill back to the lens and definitely use a lens shade. If you are getting glare your lights are too close to the painting's edge, but feathering should help that as well. In any case, you absolutely have to shoot under a controlled setup; shooting outdoors introduces too many variables. When I shoot artwork (oils, acrylics, water color, etc) I use a 100 mm macro (Canon) on the 5d MKII. Have you gone into the settings on the body to be sure you are in neutral mode with no additional contrast or sharpening? Also, you didn't say, but I assume your monitor is calibrated. Finally, I use Lightroom for output from Camera Raw to TIFF or PSD, but go straight to Photoshop for all adjustments, working in ProPhoto for editing with final output to either Adobe98 or sRGB depending on client requirements. I use a DataColor Spyder Checker 24, but in the end artwork requires visual adjustment. No matter what you do in the capture certain colors will simply not cooperate (cobalt blue for example); there is no avoiding post-production work. That said, the points I mentioned above should help you with contrast Regards, Neil Steinberg On 9/17/15 1:58 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. Art Duplication (Louis Dina) > 2. Re: Art Duplication (Andrew Rodney) > 3. Re: Art Duplication (John Castronovo) > 4. Re: Art Duplication (waynebretl(a)comcast.net) > 5. RE: Art Duplication (Roger Breton) > 6. Re: Art Duplication (Ben Goren) > 7. Re: Art Duplication (Louis Dina) > 8. Re: Art Duplication (Ben Goren) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 17 Sep 2015 09:14:50 -0500 > From: Louis Dina <lou(a)loudina.com> > To: Colorsync Users List <colorsync-users(a)lists.apple.com> > Subject: Art Duplication > Message-ID: > <CAOTaQcL8SgyxKygkb+d8c1sNQrbEy326McYzw8xZ6bP5hsMDZg(a)mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > I want to duplicate some oil paintings on canvas. The surface is > reflective, glossy, textured paints, and in places, the dimples of the > canvas are visible. The oil paintings are coated with a gloss varnish of > some sort. My tools are limited, but they'll have to do. I just want to get > as close as I can using the tools I have. First, some background. > > I'm using a Canon 5Dmk2, 85mm prime lens with circular polarizer, two Alien > Bee studio strobes on either side with polarizer gels (cross polarized to > eliminate reflections and glare) aimed at 45°angles. I'm photographing the > artwork with a small Color Checker and a Spyder Cube (for the light trap) > to help me assess tone and color. > > I built a custom camera profile using XRite Color Checker Passport and I'm > processing the images in LightRoom. I know, not perfect. > > In the past, I had a tough time getting even a lone color checker to > reproduce fairly accurately until I forced the 6 neutral patches to match > the L* values of my CC target (which I read with my Eye One with UV Cut > filter). Once I got the L* values of the 6 neutral patches right, the 18 > color patches measured fairly close to my spectro readings. Close enough > for me. My conclusion is that the default LR settings are so contrasty, > even with a "linear" Tone Curve, that it pumps everything way up and whacks > the colors. > > In LR, I apply my custom camera profile, Click-WB on the 50% gray patch > (which is the closest to dead neutral on my CC target), then manually > adjust the Tone Curve to match the neutral L* values of my CC to match my > spectro readings. My first photos of the artwork had some > flare/glare/reflection due to the high gloss shine, so when I got the CC > Target looking right, the paintings looked washed out and flat. I assumed > this was the reason the CC looked right, but the painting did not. That's > when I decided to try polarized light sources and a polarizer on the camera > lens. It definitely helped and I am pleased with the improvement. > > However, even with the polarized images, if I force the L* values of the 6 > neutral CC patches to match my spectro readings, the images still look a > bit flat and washed out. The CC itself looks great and all the patches > measure pretty close. > > I can adjust the image so it DOES look pretty accurate by eyeball, but then > the contrast of the color checker ends up being high. Mainly, I have to > darken the darken the black and Dark Gray patches so the painting looks > right. I'm hoping to come up with a method that doesn't rely so much on > memory and feel. > > I'm baffled as to why this would be? (unless I still have some flare). Any > thoughts or suggestions? (additional equipment or software is not a > consideration at this time). > > Thanks, > > Lou Dina > > > ------------------------------ > > Message: 2 > Date: Thu, 17 Sep 2015 08:37:37 -0600 > From: Andrew Rodney <andrew(a)digitaldog.net> > To: Colorsync Users List <colorsync-users(a)lists.apple.com> > Subject: Re: Art Duplication > Message-ID: <FD09C810-BC9E-4969-97B7-149F63613EC7(a)digitaldog.net> > Content-Type: text/plain; charset=us-ascii > > >> On Sep 17, 2015, at 8:14 AM, Louis Dina <lou(a)loudina.com> wrote: >> >> In LR, I apply my custom camera profile, Click-WB on the 50% gray patch >> (which is the closest to dead neutral on my CC target), then manually >> adjust the Tone Curve to match the neutral L* values of my CC to match my >> spectro readings. > You may want to rethink this patch selection. ACR/LR is really designed for linear encoded (raw) data so one is advised to white balance on the 2nd white patch. Might help. > > You might look into the free DNG camera profile editor from Adobe. Some tweaking might be necessary. > > https://www.adobe.com/support/downloads/detail.jsp?ftpID=5493 > > Andrew Rodney > http://www.digitaldog.net/ > > > ------------------------------ > > Message: 3 > Date: Thu, 17 Sep 2015 10:49:10 -0400 > From: John Castronovo <jc(a)technicalphoto.com> > To: Louis Dina <lou(a)loudina.com>, Colorsync Users List > <colorsync-users(a)lists.apple.com> > Subject: Re: Art Duplication > Message-ID: <EFD48B951B6A4BE1A96BC37F1A6AF827@castronovoden> > Content-Type: text/plain; format=flowed; charset=UTF-8; > reply-type=original > > It isn't clear from your post that you made your custom camera profile using > the identical cross-polarized setup that was used to capture the art, but > assuming that was done, I'll just add that original art is different from a > color checker in so many ways that it's a no brainer to me that one has to > make final adjustments to the scan in order to best match the original. Some > paintings require more tweaking than others, but they all need something and > profiles alone can only get us very close to the optimal result. You also > don't need to visit LR. Just assign your custom profile in Photoshop and > then convert to a wide gamut working profile and go from there. Then I add a > levels adjustment layer to set my black and white points and that gets me > very close. You won't find a one size fits all for fine art reproduction > though. It's always an interpretation. > > That said, your results are the opposite of what I'd expect. A cross > polarized setup yields too much contrast rather than too little, so you > might have too much flare or else you're not fully polarized. Maybe there's > a lot of un-polarized spill light coming from flash units, so check that > out. Also, you may discover that getting farther away from the original with > a longer lens helps with reflections and minimizes the need for polarizers > and get the lights closer to the wall than 45 degrees, but be sure to use > gobos to prevent flare causing light from reaching the camera. > > john castronovo > techphoto, llc > > > -----Original Message----- > From: Louis Dina > Sent: Thursday, September 17, 2015 10:14 AM > To: Colorsync Users List > Subject: Art Duplication > > I want to duplicate some oil paintings on canvas. The surface is > reflective, glossy, textured paints, and in places, the dimples of the > canvas are visible. The oil paintings are coated with a gloss varnish of > some sort. My tools are limited, but they'll have to do. I just want to get > as close as I can using the tools I have. First, some background. > > I'm using a Canon 5Dmk2, 85mm prime lens with circular polarizer, two Alien > Bee studio strobes on either side with polarizer gels (cross polarized to > eliminate reflections and glare) aimed at 45°angles. I'm photographing the > artwork with a small Color Checker and a Spyder Cube (for the light trap) > to help me assess tone and color. > > I built a custom camera profile using XRite Color Checker Passport and I'm > processing the images in LightRoom. I know, not perfect. > > In the past, I had a tough time getting even a lone color checker to > reproduce fairly accurately until I forced the 6 neutral patches to match > the L* values of my CC target (which I read with my Eye One with UV Cut > filter). Once I got the L* values of the 6 neutral patches right, the 18 > color patches measured fairly close to my spectro readings. Close enough > for me. My conclusion is that the default LR settings are so contrasty, > even with a "linear" Tone Curve, that it pumps everything way up and whacks > the colors. > > In LR, I apply my custom camera profile, Click-WB on the 50% gray patch > (which is the closest to dead neutral on my CC target), then manually > adjust the Tone Curve to match the neutral L* values of my CC to match my > spectro readings. My first photos of the artwork had some > flare/glare/reflection due to the high gloss shine, so when I got the CC > Target looking right, the paintings looked washed out and flat. I assumed > this was the reason the CC looked right, but the painting did not. That's > when I decided to try polarized light sources and a polarizer on the camera > lens. It definitely helped and I am pleased with the improvement. > > However, even with the polarized images, if I force the L* values of the 6 > neutral CC patches to match my spectro readings, the images still look a > bit flat and washed out. The CC itself looks great and all the patches > measure pretty close. > > I can adjust the image so it DOES look pretty accurate by eyeball, but then > the contrast of the color checker ends up being high. Mainly, I have to > darken the darken the black and Dark Gray patches so the painting looks > right. I'm hoping to come up with a method that doesn't rely so much on > memory and feel. > > I'm baffled as to why this would be? (unless I still have some flare). Any > thoughts or suggestions? (additional equipment or software is not a > consideration at this time). > > Thanks, > > Lou Dina > _______________________________________________ > 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/jc%40technicalphoto… > > This email sent to jc(a)technicalphoto.com > > > > ------------------------------ > > Message: 4 > Date: Thu, 17 Sep 2015 15:41:43 +0000 (UTC) > From: waynebretl(a)comcast.net > To: John Castronovo <jc(a)technicalphoto.com> > Cc: Louis Dina <lou(a)loudina.com>, colorsync-users > <colorsync-users(a)lists.apple.com> > Subject: Re: Art Duplication > Message-ID: > <370239507.29386348.1442504503167.JavaMail.zimbra(a)comcast.net> > Content-Type: text/plain; charset=utf-8 > > > The fact that the Color Checker reproduction appears OK argues against this problem being due to color appearance effects, but I would note that the deficiencies you see are of the type caused by color appearance changes due to viewing conditions. That is, a strict colorimetric reproduction of a scene as a print or monitor image usually appears to have less contrast and lower saturation than the source appeared to have. Viewing an image on a bright display with a dim surround in particular causes the lowlights to appear washed out, something that has been known since the early days of television. > > Again, your description of the correct-looking CC reproduction argues against this interpretation, but I just wanted to mention it for consideration. > > Wayne Bretl > ----- Original Message ----- > > From: "John Castronovo" <jc(a)technicalphoto.com> > To: "Louis Dina" <lou(a)loudina.com>, "Colorsync Users List" <colorsync-users(a)lists.apple.com> > Sent: Thursday, September 17, 2015 9:49:10 AM > Subject: Re: Art Duplication > > It isn't clear from your post that you made your custom camera profile using > the identical cross-polarized setup that was used to capture the art, but > assuming that was done, I'll just add that original art is different from a > color checker in so many ways that it's a no brainer to me that one has to > make final adjustments to the scan in order to best match the original. Some > paintings require more tweaking than others, but they all need something and > profiles alone can only get us very close to the optimal result. You also > don't need to visit LR. Just assign your custom profile in Photoshop and > then convert to a wide gamut working profile and go from there. Then I add a > levels adjustment layer to set my black and white points and that gets me > very close. You won't find a one size fits all for fine art reproduction > though. It's always an interpretation. > > That said, your results are the opposite of what I'd expect. A cross > polarized setup yields too much contrast rather than too little, so you > might have too much flare or else you're not fully polarized. Maybe there's > a lot of un-polarized spill light coming from flash units, so check that > out. Also, you may discover that getting farther away from the original with > a longer lens helps with reflections and minimizes the need for polarizers > and get the lights closer to the wall than 45 degrees, but be sure to use > gobos to prevent flare causing light from reaching the camera. > > john castronovo > techphoto, llc > > > -----Original Message----- > From: Louis Dina > Sent: Thursday, September 17, 2015 10:14 AM > To: Colorsync Users List > Subject: Art Duplication > > I want to duplicate some oil paintings on canvas. The surface is > reflective, glossy, textured paints, and in places, the dimples of the > canvas are visible. The oil paintings are coated with a gloss varnish of > some sort. My tools are limited, but they'll have to do. I just want to get > as close as I can using the tools I have. First, some background. > > I'm using a Canon 5Dmk2, 85mm prime lens with circular polarizer, two Alien > Bee studio strobes on either side with polarizer gels (cross polarized to > eliminate reflections and glare) aimed at 45°angles. I'm photographing the > artwork with a small Color Checker and a Spyder Cube (for the light trap) > to help me assess tone and color. > > I built a custom camera profile using XRite Color Checker Passport and I'm > processing the images in LightRoom. I know, not perfect. > > In the past, I had a tough time getting even a lone color checker to > reproduce fairly accurately until I forced the 6 neutral patches to match > the L* values of my CC target (which I read with my Eye One with UV Cut > filter). Once I got the L* values of the 6 neutral patches right, the 18 > color patches measured fairly close to my spectro readings. Close enough > for me. My conclusion is that the default LR settings are so contrasty, > even with a "linear" Tone Curve, that it pumps everything way up and whacks > the colors. > > In LR, I apply my custom camera profile, Click-WB on the 50% gray patch > (which is the closest to dead neutral on my CC target), then manually > adjust the Tone Curve to match the neutral L* values of my CC to match my > spectro readings. My first photos of the artwork had some > flare/glare/reflection due to the high gloss shine, so when I got the CC > Target looking right, the paintings looked washed out and flat. I assumed > this was the reason the CC looked right, but the painting did not. That's > when I decided to try polarized light sources and a polarizer on the camera > lens. It definitely helped and I am pleased with the improvement. > > However, even with the polarized images, if I force the L* values of the 6 > neutral CC patches to match my spectro readings, the images still look a > bit flat and washed out. The CC itself looks great and all the patches > measure pretty close. > > I can adjust the image so it DOES look pretty accurate by eyeball, but then > the contrast of the color checker ends up being high. Mainly, I have to > darken the darken the black and Dark Gray patches so the painting looks > right. I'm hoping to come up with a method that doesn't rely so much on > memory and feel. > > I'm baffled as to why this would be? (unless I still have some flare). Any > thoughts or suggestions? (additional equipment or software is not a > consideration at this time). > > Thanks, > > Lou Dina > _______________________________________________ > 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/jc%40technicalphoto… > > This email sent to jc(a)technicalphoto.com > > _______________________________________________ > 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%40comcas… > > This email sent to waynebretl(a)comcast.net > > > > ------------------------------ > > Message: 5 > Date: Thu, 17 Sep 2015 12:50:18 -0400 > From: Roger Breton <graxx(a)videotron.ca> > To: "'Louis Dina'" <lou(a)loudina.com>, "'Colorsync Users List'" > <colorsync-users(a)lists.apple.com> > Subject: RE: Art Duplication > Message-ID: <000e01d0f168$ef875160$ce95f420$(a)videotron.ca> > Content-Type: text/plain; charset=utf-8 > > Lou, > > FWIW, have you ever experimented with shooting under direct "noon" kind of sunlight? > > / Roger > > -----Original Message----- > From: colorsync-users-bounces+graxx=videotron.ca(a)lists.apple.com [mailto:colorsync-users-bounces+graxx=videotron.ca@lists.apple.com] On Behalf Of Louis Dina > Sent: 17 septembre 2015 10:15 > To: Colorsync Users List <colorsync-users(a)lists.apple.com> > Subject: Art Duplication > > I want to duplicate some oil paintings on canvas. The surface is reflective, glossy, textured paints, and in places, the dimples of the canvas are visible. The oil paintings are coated with a gloss varnish of some sort. My tools are limited, but they'll have to do. I just want to get as close as I can using the tools I have. First, some background. > > I'm using a Canon 5Dmk2, 85mm prime lens with circular polarizer, two Alien Bee studio strobes on either side with polarizer gels (cross polarized to eliminate reflections and glare) aimed at 45°angles. I'm photographing the artwork with a small Color Checker and a Spyder Cube (for the light trap) to help me assess tone and color. > > I built a custom camera profile using XRite Color Checker Passport and I'm processing the images in LightRoom. I know, not perfect. > > In the past, I had a tough time getting even a lone color checker to reproduce fairly accurately until I forced the 6 neutral patches to match the L* values of my CC target (which I read with my Eye One with UV Cut filter). Once I got the L* values of the 6 neutral patches right, the 18 color patches measured fairly close to my spectro readings. Close enough for me. My conclusion is that the default LR settings are so contrasty, even with a "linear" Tone Curve, that it pumps everything way up and whacks the colors. > > In LR, I apply my custom camera profile, Click-WB on the 50% gray patch (which is the closest to dead neutral on my CC target), then manually adjust the Tone Curve to match the neutral L* values of my CC to match my spectro readings. My first photos of the artwork had some flare/glare/reflection due to the high gloss shine, so when I got the CC Target looking right, the paintings looked washed out and flat. I assumed this was the reason the CC looked right, but the painting did not. That's when I decided to try polarized light sources and a polarizer on the camera lens. It definitely helped and I am pleased with the improvement. > > However, even with the polarized images, if I force the L* values of the 6 neutral CC patches to match my spectro readings, the images still look a bit flat and washed out. The CC itself looks great and all the patches measure pretty close. > > I can adjust the image so it DOES look pretty accurate by eyeball, but then the contrast of the color checker ends up being high. Mainly, I have to darken the darken the black and Dark Gray patches so the painting looks right. I'm hoping to come up with a method that doesn't rely so much on memory and feel. > > I'm baffled as to why this would be? (unless I still have some flare). Any thoughts or suggestions? (additional equipment or software is not a consideration at this time). > > Thanks, > > Lou Dina > _______________________________________________ > 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 > > > > > ------------------------------ > > Message: 6 > Date: Thu, 17 Sep 2015 10:14:04 -0700 > From: Ben Goren <ben(a)trumpetpower.com> > To: Louis Dina <lou(a)loudina.com> > Cc: Colorsync Users List <colorsync-users(a)lists.apple.com> > Subject: Re: Art Duplication > Message-ID: <E46AE755-3D41-4675-999A-6814BBBFCDA3(a)trumpetpower.com> > Content-Type: text/plain; charset="iso-8859-1" > > Lou, you're probably getting results about as good as you're going to get with your workflow. > > Colorimetric accuracy with no manual tweaking is possible, and even possible with the equipment you have at hand. But Adobe products are designed not for accuracy but "pleasing" color, so you'll have to use a different RAW processor. And 24- or 50- or even 500-patch printed charts cannot sample the camera's response to the degree needed; you need to build a model of the camera's spectral properties and create synthetic test sets to build ICC profiles from. This, obviously, is a significant departure from the workflow you're familiar with. > > To photograph the work itself, you'll need a completely blackened room; I've got black flock velvet drapes I made that I can put up and move around wherever, including over the ceiling, plus a black backdrop (from Savage, vinyl) on the floor. Put a mirror in place of the artwork and arrange the camera and lighting until both the camera is evenly lit and you can't see the lights from the camera; the lights will be much closer to the plane of the artwork than 45°, due to the fact that camera's field of view expands beyond the central point. Get this right and you likely won't need polarizers, unless the texture is dramatic -- and, in that case, a piece of clear acrylic over the art might be a better solution. Make sure no light is directly falling on the camera from the lights, even if they're not visible in the viewfinder; you might need to use flags or the like. You can use the mirror to align the camera: when the center of the lens is centered in the viewfinder, the camera's plane is parallel to that of the mirror. As a last step, drape the camera, save for the lens, in black cloth. Obviously, you'll need a remote release with you nowhere near the scene. > > Good luck.... > > Cheers, > > b& > > On Sep 17, 2015, at 7:14 AM, Louis Dina <lou(a)loudina.com> wrote: > >> I want to duplicate some oil paintings on canvas. The surface is >> reflective, glossy, textured paints, and in places, the dimples of the >> canvas are visible. The oil paintings are coated with a gloss varnish of >> some sort. My tools are limited, but they'll have to do. I just want to get >> as close as I can using the tools I have. First, some background. >> >> I'm using a Canon 5Dmk2, 85mm prime lens with circular polarizer, two Alien >> Bee studio strobes on either side with polarizer gels (cross polarized to >> eliminate reflections and glare) aimed at 45°angles. I'm photographing the >> artwork with a small Color Checker and a Spyder Cube (for the light trap) >> to help me assess tone and color. >> >> I built a custom camera profile using XRite Color Checker Passport and I'm >> processing the images in LightRoom. I know, not perfect. >> >> In the past, I had a tough time getting even a lone color checker to >> reproduce fairly accurately until I forced the 6 neutral patches to match >> the L* values of my CC target (which I read with my Eye One with UV Cut >> filter). Once I got the L* values of the 6 neutral patches right, the 18 >> color patches measured fairly close to my spectro readings. Close enough >> for me. My conclusion is that the default LR settings are so contrasty, >> even with a "linear" Tone Curve, that it pumps everything way up and whacks >> the colors. >> >> In LR, I apply my custom camera profile, Click-WB on the 50% gray patch >> (which is the closest to dead neutral on my CC target), then manually >> adjust the Tone Curve to match the neutral L* values of my CC to match my >> spectro readings. My first photos of the artwork had some >> flare/glare/reflection due to the high gloss shine, so when I got the CC >> Target looking right, the paintings looked washed out and flat. I assumed >> this was the reason the CC looked right, but the painting did not. That's >> when I decided to try polarized light sources and a polarizer on the camera >> lens. It definitely helped and I am pleased with the improvement. >> >> However, even with the polarized images, if I force the L* values of the 6 >> neutral CC patches to match my spectro readings, the images still look a >> bit flat and washed out. The CC itself looks great and all the patches >> measure pretty close. >> >> I can adjust the image so it DOES look pretty accurate by eyeball, but then >> the contrast of the color checker ends up being high. Mainly, I have to >> darken the darken the black and Dark Gray patches so the painting looks >> right. I'm hoping to come up with a method that doesn't rely so much on >> memory and feel. >> >> I'm baffled as to why this would be? (unless I still have some flare). Any >> thoughts or suggestions? (additional equipment or software is not a >> consideration at this time). >> >> Thanks, >> >> Lou Dina >> _______________________________________________ >> 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/ben%40trumpetpower.… >> >> This email sent to ben(a)trumpetpower.com >

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Re: Art Duplication (Louis Dina)
by Mike Strickler 17 Sep '15

17 Sep '15

Lou, Polarization and cross-polarization, while sometimes unavoidable, present a whole stack of color reproduction problems, partly addressed in the other responses to your question. The reference Lab values for the profiling chart must be made under the same conditions as those present in the capture of the painting. If the painting has a matte surface this is greatly simplified, but in this case not only is the instrument filtering and illuminant angle, etc, (assuming you are measuring the chart yourself to derive the ref values) are not the same as in your shooting setup, but the target is itself nothing like the painting, either in the spectral signature of its colorants (including possible fluorescing of the paints) or, more importantly, in its surface: A rough, glossy-surfaced painting will not correspond with spectrophotometer contact measurements made of a matte-surfaced target--not even close--even if you use an instrument with a polarizing filter. There may also be issues with the response of the DSLR chip to polarized light, as when a polarizing filter is placed over the taking lens. I doubt there is much you can do beyond profiling conventionally (preferably measuring with with a polarizing filter) and doing the rest of the correction manually in Photoshop. Those skills are still important! Mike

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Re: Art Duplication
by Louis Dina 17 Sep '15

17 Sep '15

Thanks for all the great feedback folks. It's a challenge to be sure. Most of my problem seems to be in setting the white and black points so my image is a good match. I'm happy with the color, but not the tonal range. What works almost perfectly for the Color Checker doesn't cut it with the painting. I'm thinking the CC patches approach a perfect, diffuse reflection, so it looks the same almost regardless of the angle and lighting. The paintings have a lot of direct reflection, shine, sheen, texture, etc, so the viewing angle and lighting make a big difference in how they look. I was hoping my cross polarized lighting would solve it. It did to a significant degree, but not completely. I'm trying to learn myself, but also trying to help a friend who took dozens of art photos with a similar setup. Unfortunately, the actual artwork is 1000 miles away, so he can't tweak to match visually. I was trying to use a "by the numbers" approach as much as possible, to reduce his reliance on memory or feel to adjust his images. John, you may be right that I didn't have my polarizers perfectly cross polarized. Also, my custom profile was made without the polarizers. Wayne, I think your comment colorimetric reproduction on a monitor is part of the issue. Roger, yes I have taken outdoor shots, with and without a polarizing filter. I got much better results with the polarizer. Still have the same black point issue. Ben…Yikes! I think you are right, but that's more than I am willing to tackle. I wouldn't be surprised if my light gray studio walls are causing light to reflect back causing flare, even with the polarizers. I'm going to try another test using a back backdrop to reduce extraneous light. All this good feedback is much appreciated!! Lou

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M0 workflow
by Scott Campbell 16 Sep '15

16 Sep '15

Has anyone successfully emulated an M0 measurement workflow using UV filters with newer ISO 3664:2009 bulbs as stated in the Guide To Print Production v13.0? Thanks! Scott

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Re: Carrying Case for iSis XL and i1Pro2
by Scott Martin 11 Sep '15

11 Sep '15

Hey Ethan. Are you saying it will hold the XL diagonally? Scott Martin www.on-sight.com > On Aug 31, 2015, at 12:04 PM, Ethan Hansen <ehansen(a)drycreekphoto.com> wrote: > > Lightware's 1217 holds an iSis and a smaller laptop with (some) room to spare. Shoving a Colorchecker in as well would work and with creatinve divider rearrangement, you should be able to squeeze in your i1.

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