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#21
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Slack wrote:
[] What is Distiller? I'm always willing to learn new stuff. http://www.adobe.com/products/acrdis/main.html |
#22
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David J Taylor wrote:
Slack wrote: [] What is Distiller? I'm always willing to learn new stuff. http://www.adobe.com/products/acrdis/main.html Open Office can export to PDF and its free! A |
#23
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In message ,
"David J Taylor" wrote: wrote: In therms of luminance, it is actually (255^2.2):1 or 196,965:1. Thanks, John. Our understanding is the same, then. I only quoted 200,000:1 Sorry; I didn't even notice that you wrote that. I read it fast, and somehow thought you were writing about 255:1. simply because if I quoted the exact number I expected someone to think I was being pedantic! I can appreciate that JPEG might be optimised in a slightly different way to TIFF so that errors are masked. By the way (for anyone else who's still reading), this 2.2 gamma figure is what some cameras call the "contrast" setting - use a smaller number when converting from linear to JPEG and you'll get more contrast, a larger number gives less contrast. Most JPEG conversions, I think, vary the gamma across the histogram. This is important if you want to keep middle grey standard, but expand or compress contrast relative to it. I really wish I had a greyscale wedge the quality of the Gretag-MacBeth color checker, but with about 10 stops of grey rectangles with steps of about 1/6 stop, or even a pie wedge to discount light roll-off. -- John P Sheehy |
#24
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#25
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wrote in message
... In message , "David J Taylor" wrote: wrote: In therms of luminance, it is actually (255^2.2):1 or 196,965:1. Thanks, John. Our understanding is the same, then. I only quoted 200,000:1 Sorry; I didn't even notice that you wrote that. I read it fast, and somehow thought you were writing about 255:1. simply because if I quoted the exact number I expected someone to think I was being pedantic! I can appreciate that JPEG might be optimised in a slightly different way to TIFF so that errors are masked. By the way (for anyone else who's still reading), this 2.2 gamma figure is what some cameras call the "contrast" setting - use a smaller number when converting from linear to JPEG and you'll get more contrast, a larger number gives less contrast. Most JPEG conversions, I think, vary the gamma across the histogram. This is important if you want to keep middle grey standard, but expand or compress contrast relative to it. I really wish I had a greyscale wedge the quality of the Gretag-MacBeth color checker, but with about 10 stops of grey rectangles with steps of about 1/6 stop, or even a pie wedge to discount light roll-off. -- John P Sheehy Re the grayscale you desire ... get a Kodak Q-13 "Kodak Color Separation Guide and Gray Scale-Small," costs something like US$20 at places such as B&H. http://www.bhphotovideo.com/bnh/cont...=1&sq=desc&Ini tialSearch=yes&O=SearchBar&A=search&Q=*&bhs=t&shs= Kodak+Q-13&image.x=10&ima ge.y=5 They are literally an "industry standard," and have been used as such for over fifty years. |
#26
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"RSD99" wrote in message news:ApmSe.707$Sx4.18@trnddc06... SNIP Re the grayscale you desire ... get a Kodak Q-13 "Kodak Color Separation Guide and Gray Scale-Small," costs something like US$20 at places such as B&H. Unfortunately the range they cover is too small for a decent DSLR. The one you'll need is e.g. the Stouffer T4110: http://www.stouffer.net/TransPage.ht...mission%20step It covers a range of approx. 10000:1 or 13.5 stops. That should be enough to be able to determine the dynamic range with a single exposure. Bart |
#27
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In message ApmSe.707$Sx4.18@trnddc06,
"RSD99" wrote: Re the grayscale you desire ... get a Kodak Q-13 "Kodak Color Separation Guide and Gray Scale-Small," costs something like US$20 at places such as B&H. http://www.bhphotovideo.com/bnh/cont...=1&sq=desc&Ini tialSearch=yes&O=SearchBar&A=search&Q=*&bhs=t&shs =Kodak+Q-13&image.x=10&ima ge.y=5 They are literally an "industry standard," and have been used as such for over fifty years. I already have this, and the quality is poor. It is glossy, and they grey rectangles are reddish. You have to use special lighting for the glare not to be an issue. -- John P Sheehy |
#28
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In message ,
"Bart van der Wolf" wrote: "RSD99" wrote in message news:ApmSe.707$Sx4.18@trnddc06... SNIP Re the grayscale you desire ... get a Kodak Q-13 "Kodak Color Separation Guide and Gray Scale-Small," costs something like US$20 at places such as B&H. Unfortunately the range they cover is too small for a decent DSLR. The one you'll need is e.g. the Stouffer T4110: http://www.stouffer.net/TransPage.ht...mission%20step It covers a range of approx. 10000:1 or 13.5 stops. That should be enough to be able to determine the dynamic range with a single exposure. That looks interesting. Do you have one? Is glare an issue? -- John P Sheehy |
#29
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