Re: A really tough jpeg conversion
Mmm not sure it is the graphics card. It is most probably the screen. And no, Mac screens are no better than PC screens :( 2011/6/3 Tim Bray tb...@textuality.com: Hah, the plot thickens. I can see the banding perfectly clearly on my everyday MacBook Pro. But on our big high-quality NEC monitor, I can't. But even on the big monitor, I can see the bands in that .png file. Interesting because this is the first time there's actually been an observable effect of the fairly limited graphics card in the laptop. Thanks everyone for making me take a second look. -T On Thu, Jun 2, 2011 at 8:55 PM, Bob Sullivan rf.sulli...@gmail.com wrote: Tim, I don't see the banding either. When I've had this kind of problem, the banding was caused by display resolution. Regards, Bob S. On Thu, Jun 2, 2011 at 2:30 PM, Charles Robinson charl...@visi.com wrote: On Jun 2, 2011, at 12:47, Larry Colen wrote: On Jun 2, 2011, at 12:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. It's not too bad here. I wonder if you're pulling an Ann and have something set to too few bits. I'm having the same issue - I cannot see the isobars/lines/whatever at all. Silky-smooth on my screen (Chrome browser on a Macbook) -Charles -- Charles Robinson - charl...@visi.com Minneapolis, MN http://charles.robinsontwins.org http://www.facebook.com/charles.robinson -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Thibault Massart aka Thibouille/Thibs -- Photo: K-7, Sigma 28/1.8 macro, FA50/1.4, DA40Ltd, K30/2.8, DA16-45, DA50-135, DA50-200, 360FGZ KX, MX, SuperA+Motor, Z1, P30 Mamiya C330+80/2.8 Sekonic L-208 FalconEyes TE300D x2 Studio flashes Laptop: Macbook 13 Unibody SnowLeo/Win7 Programing: Delphi 2009 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
Some are. The larger iMac screens, eg 24 and up, are IPS displays which don't exhibit the banding. The older iMacs and all the Mac notebooks have TN displays which do show banding. That's why I have a secondary IPS LCD monitor on my iMac that I do all my image editing on. -bmw On 11-06-04 5:17 AM, Thibouille wrote: Mmm not sure it is the graphics card. It is most probably the screen. And no, Mac screens are no better than PC screens :( 2011/6/3 Tim Braytb...@textuality.com: Hah, the plot thickens. I can see the banding perfectly clearly on my everyday MacBook Pro. But on our big high-quality NEC monitor, I can't. But even on the big monitor, I can see the bands in that .png file. Interesting because this is the first time there's actually been an observable effect of the fairly limited graphics card in the laptop. Thanks everyone for making me take a second look. -T On Thu, Jun 2, 2011 at 8:55 PM, Bob Sullivanrf.sulli...@gmail.com wrote: Tim, I don't see the banding either. When I've had this kind of problem, the banding was caused by display resolution. Regards, Bob S. On Thu, Jun 2, 2011 at 2:30 PM, Charles Robinsoncharl...@visi.com wrote: On Jun 2, 2011, at 12:47, Larry Colen wrote: On Jun 2, 2011, at 12:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. It's not too bad here. I wonder if you're pulling an Ann and have something set to too few bits. I'm having the same issue - I cannot see the isobars/lines/whatever at all. Silky-smooth on my screen (Chrome browser on a Macbook) -Charles -- Charles Robinson - charl...@visi.com Minneapolis, MN http://charles.robinsontwins.org http://www.facebook.com/charles.robinson -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
IPS doesn't mean good. IPS does mean 'not crap'. A tad different IMO. Colour restitution capabilities and uniformity are not there just because those are IPS panels. 2011/6/4 Bruce Walker bruce.wal...@gmail.com: Some are. The larger iMac screens, eg 24 and up, are IPS displays which don't exhibit the banding. The older iMacs and all the Mac notebooks have TN displays which do show banding. That's why I have a secondary IPS LCD monitor on my iMac that I do all my image editing on. -bmw On 11-06-04 5:17 AM, Thibouille wrote: Mmm not sure it is the graphics card. It is most probably the screen. And no, Mac screens are no better than PC screens :( 2011/6/3 Tim Braytb...@textuality.com: Hah, the plot thickens. I can see the banding perfectly clearly on my everyday MacBook Pro. But on our big high-quality NEC monitor, I can't. But even on the big monitor, I can see the bands in that .png file. Interesting because this is the first time there's actually been an observable effect of the fairly limited graphics card in the laptop. Thanks everyone for making me take a second look. -T On Thu, Jun 2, 2011 at 8:55 PM, Bob Sullivanrf.sulli...@gmail.com wrote: Tim, I don't see the banding either. When I've had this kind of problem, the banding was caused by display resolution. Regards, Bob S. On Thu, Jun 2, 2011 at 2:30 PM, Charles Robinsoncharl...@visi.com wrote: On Jun 2, 2011, at 12:47, Larry Colen wrote: On Jun 2, 2011, at 12:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. It's not too bad here. I wonder if you're pulling an Ann and have something set to too few bits. I'm having the same issue - I cannot see the isobars/lines/whatever at all. Silky-smooth on my screen (Chrome browser on a Macbook) -Charles -- Charles Robinson - charl...@visi.com Minneapolis, MN http://charles.robinsontwins.org http://www.facebook.com/charles.robinson -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Thibault Massart aka Thibouille/Thibs -- Photo: K-7, Sigma 28/1.8 macro, FA50/1.4, DA40Ltd, K30/2.8, DA16-45, DA50-135, DA50-200, 360FGZ KX, MX, SuperA+Motor, Z1, P30 Mamiya C330+80/2.8 Sekonic L-208 FalconEyes TE300D x2 Studio flashes Laptop: Macbook 13 Unibody SnowLeo/Win7 Programing: Delphi 2009 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
On Jun 4, 2011, at 7:05 AM, Thibouille wrote: IPS doesn't mean good. IPS does mean 'not crap'. A tad different IMO. Colour restitution capabilities and uniformity are not there just because those are IPS panels. But the new iMac IPS monitors are quite good by all accounts. I've been very satisfied with the performance of the iMac 27 monitor. Paul 2011/6/4 Bruce Walker bruce.wal...@gmail.com: Some are. The larger iMac screens, eg 24 and up, are IPS displays which don't exhibit the banding. The older iMacs and all the Mac notebooks have TN displays which do show banding. That's why I have a secondary IPS LCD monitor on my iMac that I do all my image editing on. -bmw On 11-06-04 5:17 AM, Thibouille wrote: Mmm not sure it is the graphics card. It is most probably the screen. And no, Mac screens are no better than PC screens :( 2011/6/3 Tim Braytb...@textuality.com: Hah, the plot thickens. I can see the banding perfectly clearly on my everyday MacBook Pro. But on our big high-quality NEC monitor, I can't. But even on the big monitor, I can see the bands in that .png file. Interesting because this is the first time there's actually been an observable effect of the fairly limited graphics card in the laptop. Thanks everyone for making me take a second look. -T On Thu, Jun 2, 2011 at 8:55 PM, Bob Sullivanrf.sulli...@gmail.com wrote: Tim, I don't see the banding either. When I've had this kind of problem, the banding was caused by display resolution. Regards, Bob S. On Thu, Jun 2, 2011 at 2:30 PM, Charles Robinsoncharl...@visi.com wrote: On Jun 2, 2011, at 12:47, Larry Colen wrote: On Jun 2, 2011, at 12:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. It's not too bad here. I wonder if you're pulling an Ann and have something set to too few bits. I'm having the same issue - I cannot see the isobars/lines/whatever at all. Silky-smooth on my screen (Chrome browser on a Macbook) -Charles -- Charles Robinson - charl...@visi.com Minneapolis, MN http://charles.robinsontwins.org http://www.facebook.com/charles.robinson -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Thibault Massart aka Thibouille/Thibs -- Photo: K-7, Sigma 28/1.8 macro, FA50/1.4, DA40Ltd, K30/2.8, DA16-45, DA50-135, DA50-200, 360FGZ KX, MX, SuperA+Motor, Z1, P30 Mamiya C330+80/2.8 Sekonic L-208 FalconEyes TE300D x2 Studio flashes Laptop: Macbook 13 Unibody SnowLeo/Win7 Programing: Delphi 2009 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
On Jun 4, 2011, at 4:37, Bruce Walker wrote: Some are. The larger iMac screens, eg 24 and up, are IPS displays which don't exhibit the banding. The older iMacs and all the Mac notebooks have TN displays which do show banding. That's why I have a secondary IPS LCD monitor on my iMac that I do all my image editing on. 3-year-old Macbook here and I cannot see any banding whatsoever. -Charles -- Charles Robinson - charl...@visi.com Minneapolis, MN http://charles.robinsontwins.org http://www.facebook.com/charles.robinson -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
Which is good news, undoubtetly. But I'd be surprises if the gamut of mac screens is anything to write about. Note I myself have a mac so this is no Free mac bashing. Le samedi 4 juin 2011, Paul Stenquist pnstenqu...@comcast.net a écrit : On Jun 4, 2011, at 7:05 AM, Thibouille wrote: IPS doesn't mean good. IPS does mean 'not crap'. A tad different IMO. Colour restitution capabilities and uniformity are not there just because those are IPS panels. But the new iMac IPS monitors are quite good by all accounts. I've been very satisfied with the performance of the iMac 27 monitor. Paul 2011/6/4 Bruce Walker bruce.wal...@gmail.com: Some are. The larger iMac screens, eg 24 and up, are IPS displays which don't exhibit the banding. The older iMacs and all the Mac notebooks have TN displays which do show banding. That's why I have a secondary IPS LCD monitor on my iMac that I do all my image editing on. -bmw On 11-06-04 5:17 AM, Thibouille wrote: Mmm not sure it is the graphics card. It is most probably the screen. And no, Mac screens are no better than PC screens :( 2011/6/3 Tim Braytb...@textuality.com: Hah, the plot thickens. I can see the banding perfectly clearly on my everyday MacBook Pro. But on our big high-quality NEC monitor, I can't. But even on the big monitor, I can see the bands in that .png file. Interesting because this is the first time there's actually been an observable effect of the fairly limited graphics card in the laptop. Thanks everyone for making me take a second look. -T On Thu, Jun 2, 2011 at 8:55 PM, Bob Sullivanrf.sulli...@gmail.com wrote: Tim, I don't see the banding either. When I've had this kind of problem, the banding was caused by display resolution. Regards, Bob S. On Thu, Jun 2, 2011 at 2:30 PM, Charles Robinsoncharl...@visi.com wrote: On Jun 2, 2011, at 12:47, Larry Colen wrote: On Jun 2, 2011, at 12:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. It's not too bad here. I wonder if you're pulling an Ann and have something set to too few bits. I'm having the same issue - I cannot see the isobars/lines/whatever at all. Silky-smooth on my screen (Chrome browser on a Macbook) -Charles -- Charles Robinson - charl...@visi.com Minneapolis, MN http://charles.robinsontwins.org -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Thibault Massart aka Thibouille/Thibs -- Photo: K-7, Sigma 28/1.8 macro, FA50/1.4, DA40Ltd, K30/2.8, DA16-45, DA50-135, DA50-200, 360FGZ KX, MX, SuperA+Motor, Z1, P30 Mamiya C330+80/2.8 Sekonic L-208 FalconEyes TE300D x2 Studio flashes Laptop: Macbook 13 Unibody SnowLeo/Win7 Programing: Delphi 2009 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
On 6/2/2011 10:11, Tim Bray wrote: I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. Tim, what happens if you save this picture as an uncompressed TIFF file? Methinks that if you will still get issues - the problem is not in compression or JPG or may be not as much in this. It may be emphasized by the JPG artifacts but it may be elsewhere. Just my cents. Boris -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
They seem like signs of posterization to me. Unfortunately, I do not know what can be done for your particular image to prevent them forming. Bulent - http://www.flickr.com/photos/bc_the_path/ http://photo.net/photodb/user?user_id=2226822 http://www.pentaxphotogallery.com/bulentcelasun -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
On 11-06-02 3:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! PNG is not lossy like JPEG, but it is compressed. The compression is not as efficient as JPEG because it can't play tricks that lossy conversions can. I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. -Tim I'm barely seeing your bars; they are not *that* obvious. Assuming your toolchain is 100% 16-bit (or better) end-to-end, then your image is suffering from banding by being dithered down to 8-bits at the output. JPEG is 8-bits RGB, so you are most likely introducing banding right there. Also as for your PNG image, there's 16-bit PNG and 8-bit PNG, and you used 8-bit, which will show clear banding same as the JPEG. screen-grab.png: PNG image, 764 x 727, 8-bit/color RGB, non-interlaced Even 16-bit images can suffer from very slight banding in really gradual tonal transitions. The solution to that is to dither the image a bit -- add some intentional noise. You could use a mask in Photoshop to restrict the noise addition to just the darker bokeh areas and avoid mucking-up the bloom. There's a grain feature in LR (bottom of the Develop section) that you could play with to add some noise. And that's a _great_ shot, btw. My only issue with it is I can't see the stem which makes it look a little floating in space, but I guess that's because of the angle of view. You've struck an excellent balance with the DoF / sharp edges / bokeh. -bmw -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
Mmm wouldn't a proper PS conversion to 8bit cure the problem and saving later to 8bit Jpeg rather than 16bit image directly exported to 8bit Jpeg ? 2011/6/2 Bruce Walker bruce.wal...@gmail.com: On 11-06-02 3:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! PNG is not lossy like JPEG, but it is compressed. The compression is not as efficient as JPEG because it can't play tricks that lossy conversions can. I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. -Tim I'm barely seeing your bars; they are not *that* obvious. Assuming your toolchain is 100% 16-bit (or better) end-to-end, then your image is suffering from banding by being dithered down to 8-bits at the output. JPEG is 8-bits RGB, so you are most likely introducing banding right there. Also as for your PNG image, there's 16-bit PNG and 8-bit PNG, and you used 8-bit, which will show clear banding same as the JPEG. screen-grab.png: PNG image, 764 x 727, 8-bit/color RGB, non-interlaced Even 16-bit images can suffer from very slight banding in really gradual tonal transitions. The solution to that is to dither the image a bit -- add some intentional noise. You could use a mask in Photoshop to restrict the noise addition to just the darker bokeh areas and avoid mucking-up the bloom. There's a grain feature in LR (bottom of the Develop section) that you could play with to add some noise. And that's a _great_ shot, btw. My only issue with it is I can't see the stem which makes it look a little floating in space, but I guess that's because of the angle of view. You've struck an excellent balance with the DoF / sharp edges / bokeh. -bmw -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Thibault Massart aka Thibouille/Thibs -- Photo: K-7, Sigma 28/1.8 macro, FA50/1.4, DA40Ltd, K30/2.8, DA16-45, DA50-135, DA50-200, 360FGZ KX, MX, SuperA+Motor, Z1, P30 Mamiya C330+80/2.8 Sekonic L-208 FalconEyes TE300D x2 Studio flashes Laptop: Macbook 13 Unibody SnowLeo/Win7 Programing: Delphi 2009 -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
On 11-06-02 9:25 AM, Thibouille wrote: Mmm wouldn't a proper PS conversion to 8bit cure the problem and saving later to 8bit Jpeg rather than 16bit image directly exported to 8bit Jpeg ? That might work best in this case, but it depends entirely on the quality of that 16-8 bit conversion. It would just have to be tried to see. I was thinking about this during my doggy walk (she was not amused) and I realized that the dithering will only work well if different random noise is added to each of the R, G, and B channels separately. Adding grain in LR will *not* do that, so while it might help, the noise may well disrupt the image too much too. Depends on how much you like grain, I guess. :-) In Photoshop at least, you can easily open the Channels panel, select each of the RGB channels in turn and add a small percentage of noise. Then you could do the JPEG conversion and see what happens. This problem exists in the audio domain too. In poorly mastered CDs you can hear popcorn noise if you crank the volume during really quiet passages. A couple of companies have made some good coin marketing 24-16 bit dithering devices (and plugins for digital audio workstations) that introduce very specific noise to eliminate the audio-level banding that would otherwise occur. -bmw 2011/6/2 Bruce Walkerbruce.wal...@gmail.com: On 11-06-02 3:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! PNG is not lossy like JPEG, but it is compressed. The compression is not as efficient as JPEG because it can't play tricks that lossy conversions can. I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. -Tim I'm barely seeing your bars; they are not *that* obvious. Assuming your toolchain is 100% 16-bit (or better) end-to-end, then your image is suffering from banding by being dithered down to 8-bits at the output. JPEG is 8-bits RGB, so you are most likely introducing banding right there. Also as for your PNG image, there's 16-bit PNG and 8-bit PNG, and you used 8-bit, which will show clear banding same as the JPEG. screen-grab.png: PNG image, 764 x 727, 8-bit/color RGB, non-interlaced Even 16-bit images can suffer from very slight banding in really gradual tonal transitions. The solution to that is to dither the image a bit -- add some intentional noise. You could use a mask in Photoshop to restrict the noise addition to just the darker bokeh areas and avoid mucking-up the bloom. There's a grain feature in LR (bottom of the Develop section) that you could play with to add some noise. And that's a _great_ shot, btw. My only issue with it is I can't see the stem which makes it look a little floating in space, but I guess that's because of the angle of view. You've struck an excellent balance with the DoF / sharp edges / bokeh. -bmw -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
On Jun 2, 2011, at 12:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. It's not too bad here. I wonder if you're pulling an Ann and have something set to too few bits. -Tim -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- Larry Colen l...@red4est.com sent from i4est -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
On Jun 2, 2011, at 12:47, Larry Colen wrote: On Jun 2, 2011, at 12:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. It's not too bad here. I wonder if you're pulling an Ann and have something set to too few bits. I'm having the same issue - I cannot see the isobars/lines/whatever at all. Silky-smooth on my screen (Chrome browser on a Macbook) -Charles -- Charles Robinson - charl...@visi.com Minneapolis, MN http://charles.robinsontwins.org http://www.facebook.com/charles.robinson -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
Tim, I don't see the banding either. When I've had this kind of problem, the banding was caused by display resolution. Regards, Bob S. On Thu, Jun 2, 2011 at 2:30 PM, Charles Robinson charl...@visi.com wrote: On Jun 2, 2011, at 12:47, Larry Colen wrote: On Jun 2, 2011, at 12:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. It's not too bad here. I wonder if you're pulling an Ann and have something set to too few bits. I'm having the same issue - I cannot see the isobars/lines/whatever at all. Silky-smooth on my screen (Chrome browser on a Macbook) -Charles -- Charles Robinson - charl...@visi.com Minneapolis, MN http://charles.robinsontwins.org http://www.facebook.com/charles.robinson -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
Re: A really tough jpeg conversion
Hah, the plot thickens. I can see the banding perfectly clearly on my everyday MacBook Pro. But on our big high-quality NEC monitor, I can't. But even on the big monitor, I can see the bands in that .png file. Interesting because this is the first time there's actually been an observable effect of the fairly limited graphics card in the laptop. Thanks everyone for making me take a second look. -T On Thu, Jun 2, 2011 at 8:55 PM, Bob Sullivan rf.sulli...@gmail.com wrote: Tim, I don't see the banding either. When I've had this kind of problem, the banding was caused by display resolution. Regards, Bob S. On Thu, Jun 2, 2011 at 2:30 PM, Charles Robinson charl...@visi.com wrote: On Jun 2, 2011, at 12:47, Larry Colen wrote: On Jun 2, 2011, at 12:11 AM, Tim Bray wrote: Check out http://www.tbray.org/ongoing/When/201x/2011/06/01/-big/RUNE0790.jpg.html Look at the green bokeh-fied background and observe the obvious lines that look like elevation lines on a map, let's call them bars, as the green brightness drops off. They ain't there in the .dng, and after the first cut, I specified 100% JPG quality and they're still obvious. It gets weird... I took a screen grab of the Lightroom window, in which none of those bars are visible, and saved to a .png file, using built-in OS X facilities, the PNG created by Preview. Obvious bars! I put it online at http://www.tbray.org/tmp/screen-grab.png - I thought .png was uncompressed! I'm sure that a silky-smooth jpg of this picture could be created. But I don't know how. It's not too bad here. I wonder if you're pulling an Ann and have something set to too few bits. I'm having the same issue - I cannot see the isobars/lines/whatever at all. Silky-smooth on my screen (Chrome browser on a Macbook) -Charles -- Charles Robinson - charl...@visi.com Minneapolis, MN http://charles.robinsontwins.org http://www.facebook.com/charles.robinson -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions. -- PDML Pentax-Discuss Mail List PDML@pdml.net http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
