10-Bit vs 8-Bit Color

Martin Chab · August 29th, 2008, 09:28 AM

I´ve made a filming not long ago to transfer to cine. We used an Canon XLH1 and captured with a BlackMagic directly to the computer in 4:2:2 10 bits uncompressed. we monitored at the same time through a blackmagic HDLink to a cheap Samsung 24 inches 1920x1200 screen. Man, you could see every single pixel!! For that I had to put four SATA (500 Gb each) in stripped raid (it was the only way to get enough speed for the capture, in fact with two or three disc the speed was ok but when the discs start to get half full the transfer rate drops dramatically). To make the color grading I used a NEC Spectraview 26 inches calibrated with an Greta macbeth eye one. The beauty of this monitor is that, even if it 8 bits, is wide gamut (shows the full adobe rgb gamut) and the calibration is stored in the monitor hardware. I used the cineon LUT as the target (I tried to get the LUT from the lab to match their printer but it was impossible, why? is a long story). I made a very extreme color grading full of secondaries (it was pretty easy to qualify for the secs). The quality was superb. At the lab one of the engineers asked for details thinking that it was made on film. In the other hand the 35mm printed version matched the colors and contrast incredibly well it was really WISIWIG.

Bill Ravens · August 29th, 2008, 09:37 AM

Martin...

I'm a little surprised at your use of the Gretag Macbeth. The color mapping this tool generates is designed to replicate, as close as possible on a computer monitor, paper printer colors, not film colors. If you used a 3rd party LUT, that may have overridden the color map from the Gretag, and kept you from further problems.

Martin Chab · August 30th, 2008, 02:31 AM

Bill,
I used the Eye one together with the spectraview profiler software. The instrument (in this case the eye one) is only the interface for the software to read the colors from the screen. The soft "talk" with the screen hardware and make a software/hardware calibration. You can choose whatever the LUT you want as the target and the system try to match that LUT as much as possible and then dump that LUT to the monitor hardware plus an extra profile on the operative system if you like. Of course there are higher end instruments but the eye one worked great in this case.
I made some tests and bring to the lab (Egmont Nordisk Lab) in Denmark. We compared the tests between my system and their flame station with two different monitors (calibrated by Arri tech service), at the monitor in the printer room and at their Color Grading room with a CRT broadcasting monitor withy their LUT and then the printed version in 35 mm and the material always matched perfectly (it was hard to see any difference)

Martin Chab · August 30th, 2008, 02:42 AM

I forgot to tell you that i didnt use any woking lut, i just used the calibrated monitor targeted to the cineon curve. For more details I worked in linear. I made some tests going to log but the difference was not enough to make it worth for that specific footage.

Peter Moretti · August 30th, 2008, 03:14 AM

Quote:

Originally Posted by Martin Chab

I´ve made a filming not long ago to transfer to cine. We used an Canon XLH1 and captured with a BlackMagic directly to the computer in 4:2:2 10 bits uncompressed. ...

Martin, and yet from everything I've read the XL-H1 does not spit out true 10-bit color. It's 8-bit color. The last two bits are padded with 0's to meet the HD-SDI spec, but they're meaningless.

That said, I've seen amazing color from the XL-H1, which makes me really wonder how much those extra two bits provide.

Martin Chab · August 30th, 2008, 04:28 AM

I really cant tell you how much that two bits provide. What I can tell you for sure is that the footage coming from the tape and the same footage coming from the SDI when color graded with exactly the same settings (remember that it was some extreme C. grading) the picture coming from the tape showed some banding and the one coming from he SDI was absolutely free of banding. May be was the difference on chroma sampling? (4:2:0 vs 4:2:2) may be the 10 bits vs 8 bits? i dont know.

Christopher Ruffell · September 2nd, 2008, 12:46 PM

I'm also sure the XL-H1 is 8-bit too.

However, that doesn't detract from the footage since i'm sure the footage Martin was seeing is incredible! 4:2:2 8-bit uncompressed is beautiful - though it'd be even more wonderful to work in 10bits ;) I can attest, I *never* see banding with the uncompressed 8-bit footage I've shot (I have a 14-bit out to my analogue HDTV and I can't detect any banding on it either).

Martin, is there anyway I can see some clips/stills/footage from this project you worked on?

I've been shooting uncompressed for a year now. I just did two videos in the last two weeks that were shot uncompressed HD-SDI to my Blackmagic card - shot from a Canon HV20 and the results are impressive - would love to see others' results as well!

I'd like to see someone's results of shooting uncompressed with the 10bit EX1.

Martin Chab · September 2nd, 2008, 01:27 PM

Christoffer,
I have an Ex1, tomorrow is returning from the service (update of firmware and so on).I will make a test capturing 10 bits uncompressed and post the images. About posting the images from the film with the XlH1 i will ask the director for permission since the movie is not released yet.

Christopher Ruffell · September 2nd, 2008, 01:32 PM

Martin, that's fantastic - thank you! Now I'm all excited to see 10-bit .PNGs!

Martin Chab · September 8th, 2008, 02:32 PM

i´m trying to post full size pngs but the system doesnt accept it. I´ll try another way.

Christopher Ruffell · September 8th, 2008, 02:42 PM

Thanks Martin!

Martin Chab · September 8th, 2008, 03:18 PM

ok, here we go: Untitled Document
this pics are from the movie Storstad (the big city). The footage was captured uncompressed 10 bits with a Blackmagic from the SDI of an XLH1 fitted with a Mini35 . The lenses were from a Leica prime set. For the lighting i used only two Falcon eyes (cheap Kinoflo) 200W each, 2 softboxes 1000W each, 2 750W fresnels and one 1K fresnel and some pieces of 1/2B filter plus some pieces of diffusion paper.
The Color grading was made in Apple Color and the compositing in AE (for example the fan I added in post, is an animation made from stills of the fan).
In some pictures you can see some banding, that comes from the grabbing of this pics, the footage doesnt show any banding.
I made also some tests with the Ex1 to compare the material coming from the SxS and the Blackmagic capture but i´ll post later on because I cant upload it here.

Martin Chab · September 8th, 2008, 03:39 PM

here SxS vs SDI (comparison) - The Digital Video Information Network is the first pic from the EX1

September 8th, 2008, 02:42 PM	#26
Christopher Ruffell Major Player Join Date: Jan 2008 Location: Victoria, BC Posts: 202	Excited Thanks Martin!

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August 29th, 2008, 09:28 AM	#16
Martin Chab Regular Crew Join Date: Apr 2006 Location: Malmo Sweden Posts: 103	I´ve made a filming not long ago to transfer to cine. We used an Canon XLH1 and captured with a BlackMagic directly to the computer in 4:2:2 10 bits uncompressed. we monitored at the same time through a blackmagic HDLink to a cheap Samsung 24 inches 1920x1200 screen. Man, you could see every single pixel!! For that I had to put four SATA (500 Gb each) in stripped raid (it was the only way to get enough speed for the capture, in fact with two or three disc the speed was ok but when the discs start to get half full the transfer rate drops dramatically). To make the color grading I used a NEC Spectraview 26 inches calibrated with an Greta macbeth eye one. The beauty of this monitor is that, even if it 8 bits, is wide gamut (shows the full adobe rgb gamut) and the calibration is stored in the monitor hardware. I used the cineon LUT as the target (I tried to get the LUT from the lab to match their printer but it was impossible, why? is a long story). I made a very extreme color grading full of secondaries (it was pretty easy to qualify for the secs). The quality was superb. At the lab one of the engineers asked for details thinking that it was made on film. In the other hand the 35mm printed version matched the colors and contrast incredibly well it was really WISIWIG.

August 29th, 2008, 09:37 AM	#17
Bill Ravens Join Date: Nov 2001 Location: santa fe, nm Posts: 3,264 Images: 10	Martin... I'm a little surprised at your use of the Gretag Macbeth. The color mapping this tool generates is designed to replicate, as close as possible on a computer monitor, paper printer colors, not film colors. If you used a 3rd party LUT, that may have overridden the color map from the Gretag, and kept you from further problems.

August 30th, 2008, 02:31 AM	#18
Martin Chab Regular Crew Join Date: Apr 2006 Location: Malmo Sweden Posts: 103	Bill, I used the Eye one together with the spectraview profiler software. The instrument (in this case the eye one) is only the interface for the software to read the colors from the screen. The soft "talk" with the screen hardware and make a software/hardware calibration. You can choose whatever the LUT you want as the target and the system try to match that LUT as much as possible and then dump that LUT to the monitor hardware plus an extra profile on the operative system if you like. Of course there are higher end instruments but the eye one worked great in this case. I made some tests and bring to the lab (Egmont Nordisk Lab) in Denmark. We compared the tests between my system and their flame station with two different monitors (calibrated by Arri tech service), at the monitor in the printer room and at their Color Grading room with a CRT broadcasting monitor withy their LUT and then the printed version in 35 mm and the material always matched perfectly (it was hard to see any difference)

August 30th, 2008, 02:42 AM	#19
Martin Chab Regular Crew Join Date: Apr 2006 Location: Malmo Sweden Posts: 103	I forgot to tell you that i didnt use any woking lut, i just used the calibrated monitor targeted to the cineon curve. For more details I worked in linear. I made some tests going to log but the difference was not enough to make it worth for that specific footage.

August 30th, 2008, 04:28 AM	#21
Martin Chab Regular Crew Join Date: Apr 2006 Location: Malmo Sweden Posts: 103	I really cant tell you how much that two bits provide. What I can tell you for sure is that the footage coming from the tape and the same footage coming from the SDI when color graded with exactly the same settings (remember that it was some extreme C. grading) the picture coming from the tape showed some banding and the one coming from he SDI was absolutely free of banding. May be was the difference on chroma sampling? (4:2:0 vs 4:2:2) may be the 10 bits vs 8 bits? i dont know.

September 2nd, 2008, 12:46 PM	#22
Christopher Ruffell Major Player Join Date: Jan 2008 Location: Victoria, BC Posts: 202	I'm also sure the XL-H1 is 8-bit too. However, that doesn't detract from the footage since i'm sure the footage Martin was seeing is incredible! 4:2:2 8-bit uncompressed is beautiful - though it'd be even more wonderful to work in 10bits ;) I can attest, I never see banding with the uncompressed 8-bit footage I've shot (I have a 14-bit out to my analogue HDTV and I can't detect any banding on it either). Martin, is there anyway I can see some clips/stills/footage from this project you worked on? I've been shooting uncompressed for a year now. I just did two videos in the last two weeks that were shot uncompressed HD-SDI to my Blackmagic card - shot from a Canon HV20 and the results are impressive - would love to see others' results as well! I'd like to see someone's results of shooting uncompressed with the 10bit EX1.

September 2nd, 2008, 01:27 PM	#23
Martin Chab Regular Crew Join Date: Apr 2006 Location: Malmo Sweden Posts: 103	Christoffer, I have an Ex1, tomorrow is returning from the service (update of firmware and so on).I will make a test capturing 10 bits uncompressed and post the images. About posting the images from the film with the XlH1 i will ask the director for permission since the movie is not released yet.

September 2nd, 2008, 01:32 PM	#24
Christopher Ruffell Major Player Join Date: Jan 2008 Location: Victoria, BC Posts: 202	Martin, that's fantastic - thank you! Now I'm all excited to see 10-bit .PNGs!

September 8th, 2008, 02:32 PM	#25
Martin Chab Regular Crew Join Date: Apr 2006 Location: Malmo Sweden Posts: 103	i´m trying to post full size pngs but the system doesnt accept it. I´ll try another way.

September 8th, 2008, 03:18 PM	#27
Martin Chab Regular Crew Join Date: Apr 2006 Location: Malmo Sweden Posts: 103	ok, here we go: Untitled Document this pics are from the movie Storstad (the big city). The footage was captured uncompressed 10 bits with a Blackmagic from the SDI of an XLH1 fitted with a Mini35 . The lenses were from a Leica prime set. For the lighting i used only two Falcon eyes (cheap Kinoflo) 200W each, 2 softboxes 1000W each, 2 750W fresnels and one 1K fresnel and some pieces of 1/2B filter plus some pieces of diffusion paper. The Color grading was made in Apple Color and the compositing in AE (for example the fan I added in post, is an animation made from stills of the fan). In some pictures you can see some banding, that comes from the grabbing of this pics, the footage doesnt show any banding. I made also some tests with the Ex1 to compare the material coming from the SxS and the Blackmagic capture but i´ll post later on because I cant upload it here.

September 8th, 2008, 03:39 PM	#28
Martin Chab Regular Crew Join Date: Apr 2006 Location: Malmo Sweden Posts: 103	here SxS vs SDI (comparison) - The Digital Video Information Network is the first pic from the EX1