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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

DreamColor LP2480zx and Scratch

Evangelos Achillopoulos said:
Simon (flameop), thanks for your kind words,

I'm having the same problems as you guys, I have to find a proper monitor. My last FW900 CRT has just being dead... A client from Israel Ido Korila just got one refurbished... He tried to calibrate and profile a JVC broadcast LCD and it wasn't successful to much decoupling error, thats lack of gamut... The FW900 was just one day of attention and evuala the profile is almost perfect...

The EIZO CG241W didnt make it, the JVC DT24 didnt make it either...

The best profile until now its from the projector JVC DLA-HD1 connected to an ATI 1900 card threw a DVI to HDMI cable... The new JVC DLA-HD100 with HDMI 1,3 (10bit RGB) is super...

I see the Dreamcolor, because of the 1,3 HDMI, as a possible contended but I dont have it in hand to test it I will request a demo from HP... but whatever is reaching the 3K euros mark it make s more sexy to have a projector (even in a close distance) because you have reflected light and not transmitted... the reflected is better because you have the same form of light as the film projection...

As for LUTs and film out as I said in the past there is NO generic LUT for film out that will give an acurrate (98%) representation of what you will see in the projection.

LUTs are created specifically for your display device and they are good for couple of days, if you don't turn off your monitor... even as a sleep mode.

If you use generic then its expected a 60% accuracy if you are lucky... same will claim better performance, but I being there done that, and its bad really bad...

LUT's are depended on filmrecorder/developing-lab/negative-emulsion/positive-emulsion relation and its very hard to make that relation 100% repeatable. So as I have said if you want to do a filmout with custom LUT's you have two solutions either go to your filmout facility and do the grading in their calibrated viewing room and pay the premium or partner with a LAB that is willing to transfer to you all his know how in color managment and get from him the LUT's.

We are doing the last one, we offer the know how for a very small on time fee and then we supply free LUT's for your sessions and we print your film in our recorders... Lasergraphics and Arrilaser... CRT for camera negative and Laser for internegative. All that in a very competitive pricing.

Thats it, simple... my email is Lakis@motionfx.gr Gabriele...

Attached are the Cinespace decoupling errors from various clients around the world, first two are from the FW900 then its the EIZO CG241W then the JVC DL24 and then the best performer the JVC DLA-HD1 projector...
Click to expand...
Evangelos,

Isn't it true that decoupling error is an issue w/ 1-D LUTs? And that a 3-D LUT will not have this error since it works on R, G and B independently?

(I'm still new to this field, so I don't mean to sound smarter than I actually am, LOL.)
 
Gabrielle, Bobby...

Ido at Israel has just completed successfully a full cycle test, he used an FW900...

http://www.reduser.net/forum/showthread.php?t=18545

In the next days I will test projectors for the job since I strongly suggest that reflected light is much better than transmitted light, so when I will finish my research, that will take some time, I will have an answer until then JVC HD100 is the best and alternatively the FW900 still is the best. A projector can be used in a small room 4m x 3m easily, Blase at Contact Studios NY is using it very successfully in a room of 5m x 3m... Unfortunately neither Blackmagic supports 4:4:4 10bit HDMI, they do 1,2, so only 4:2:2 10bit in blackmagic, which is worst than 4:4:4 8bit... probably a new Nvidia or the 4000 ATI will do it...

Its true the 3D LUT is "trying to fix" the lack of gamut, but even then, the image is really ugly to show to a client and ask him to imagine how good it will be in the film projection...
 
Hey guys.

- 10 bit YCbCr 4:2:2 = 20 bit
- 8 bit RGB = 24 bit
- 10 bit RGB = 30 bit

10 bit SDI usually have YCbCr encoding, and uses only 2x10 bit channels, 10 bit for luma and 10bit for chroma. So 3x8 RGB bit is more.

Sometimes when people say 12bit color, they just mean 10+12 bit = 22 bit

http://en.wikipedia.org/wiki/Serial_Digital_Interface

Cheers
 
Evangelos Achillopoulos said:
... Unfortunately neither Blackmagic supports 4:4:4 10bit HDMI, they do 1,2, so only 4:2:2 10bit in blackmagic, which is worst than 4:4:4 8bit... probably a new Nvidia or the 4000 ATI will do it...
Click to expand...

Evangelos, thank you very much for the reply.

So if I understand correctly, wouldn't DVI or DSub actually provide a higher quality signal than HD-SDI or HDMI 2? As HD-SDI and HDMI 2 are 4:2:2 (YUV) 10 bit, while (I believe) DVI is 4:4:4 (RGB) 8bit and DSub is just DVI converted to analog.

Thanks again.
 
DreamColor LP2480zx

DreamColor LP2480zx

I thought I would get the thread back on the topic of the HP monitor...

I purchased an LP2480zx last week, and am generally pleased with it. Great blacks, rich color, best viewing angle I've seen for the price, and LUT calibration.

I'm currrently grading about 25 spots shot with six RED cameras in Apple Color (they converted all .r3d files to ProResHQ). We're monitoring via a Kona LHe SDI 4:2:2 out into an HDLink box into the DreamColor. I also have a Sony PVM-14L5/1 for comparison via the analog outs of the card.

A few things about the monitor:

-I think the built-in calibration (i.e., colorspace selection) can only be used via DVI. Those options were greyed out when connecting a Blue-Ray player via HDMI, and an HD signal via component.

-The Rec-709 calibration is not perfect. I am unsure if their specific probe would help fix this in my setup (HDLink), as I think it might only be useful if you are connected directly to a graphics card. When connected to the graphics card directly, Rec-709 did not look anywhere close to how it looks via my HDLink. Also, the default Rec-709 puts brightness at around 49 footlamberts (actually higher than the SMPTE spec ot 24 or 29), however that was way too dark so I adjusted it by to eye to 150 FL. I also had to correct the white point slightly using the HDLink 1D LUT panel.

-Component input was crap. This was no surprise as I don't think the analog hardware is designed the way it is on a video monitor (i.e., my PVM or even my Panasonic consumer plasma). The signal was too saturated and colors were askew.

-There is little to no documentation as to how the calibration works, and again, what their probe would be useful for. I have tried to set the white point with an Eye-One Display2, but it ended up being way too warm. I wonder if that probe cannot accurately read LED screens.

I previously was using a similar setup. I had an Eizo CG241 with a Blackmagic HDLink Pro. I demo'd cineCube to try and generate a 3D LUT in REC-709 space. I was unsuccessful in finding a target profile that looked accurate (cineSpace provides two), and that is a whole other thread based on endless hours of testing... I placed that setup next to a JVC DT-V24L1DU, and they looked almost identical. But BOTH of those displays had terrible off-axis viewing. This HP blows viewing angle out of the water, and the Rec-709 LUT gets very close. I just need to find out how to calibrate it internally (there are no adjustments allowed besides xy mappings, black level, brightness). Perhaps that is what the HP probe is for, and maybe using it would calibrate the white point properly. The image also seems a tad saturated using this LUT.

In direct correspondence with BlackMagic, I was told none of their products (converters, cards, or otherwise) support the HDMI 1.3 spec to provide the 10-bit "deep color." This is from the horse's mouth. So far, I've yet to hear of a solution for getting SDI into this unit and maintaining 10-bits without compression or compromise.

Blair mentions he has dual-link DVI on his Multibridge, which sounds promising, though in my research the Multibridge doesn't have more than one DVI out.

We're always on the bleeding edge....

Andrew Huebscher
Los Angeles, CA
 
Hyperfocal,

It seems that almost no desktop monitor maker really implelments Rec 709 well. The gamma is more complicated than just plugging in 2.2. It has a linear portion at the darkest end. And even when when 2.2 is used for the expansion, the resulting value is then multiplied and divided by scaling factors, FWIU.

If I understand your post correctly, it seems that you were able to get the Eizo CG241's Rec 709 close to DreamColor's, but its off-angle viewing is nowhere near as good. Is that correct?
 
In direct correspondence with BlackMagic, I was told none of their products (converters, cards, or otherwise) support the HDMI 1.3 spec to provide the 10-bit "deep color." This is from the horse's mouth. So far, I've yet to hear of a solution for getting SDI into this unit and maintaining 10-bits without compression or compromise.
Click to expand...


Ohhh I didnt read the "none" word... sorry Andrew I know the same...


"I have talked with BMD guys on the phone and they told me from the USA office that they don't support 1,3... Andrew, can you be more specific?"
 
BobbyMurcerFan said:
Hyperfocal,

It seems that almost no desktop monitor maker really implelments Rec 709 well. The gamma is more complicated than just plugging in 2.2. It has a linear portion at the darkest end. And even when when 2.2 is used for the expansion, the resulting value is then multiplied and divided by scaling factors, FWIU.

If I understand your post correctly, it seems that you were able to get the Eizo CG241's Rec 709 close to DreamColor's, but its off-angle viewing is nowhere
near as good. Is that correct?
Click to expand...

Yes the linear portion of the shadows seem to be the hardest to map to an LCD, and that was my difficulty with cineSpace's HD targets (though their film targets, when taken through filmout tests, proved to be very accurate). When I dial in the DreamColor where I like it, I actually lose the 7.5 pluge bar, but it's the only way to put the black level where it needs to be compared to a CRT.

I did not do a side-by-side of the HP against the Eizo, so my accounts are based on how footage looked from memory (footage I shot and colored) on the Eizo against the current HP. Again, the Eizo had a 3D LUT generated by cineSpace inserted into the HDLink Pro (a process that took a bit of time to figure out).

The viewing angle of the DreamColor is excellent, as is the black level. It exceeds the Eizo in both of these areas. With the Eizo, even looking at it dead on, I would still see a change in contrast in the far corners of the screen. Eizo makes a great display, but IMO unsuitable for any environment where more than one viewer (I think that's part of the reasoning behind the hood).


Andrew Huebscher
Los Angeles, CA
 
Also, the default Rec-709 puts brightness at around 49 footlamberts (actually higher than the SMPTE spec ot 24 or 29), however that was way too dark so I adjusted it by to eye to 150 FL
Click to expand...

150FL!!!? You are joking surely, that would be as bright as the sun... That is nearly 500 CD/M2, ten times brighter than a cinema screen...

I can only assume your measurement device is reading CD/M2, or it is very broken.
 
Doh! I double checked, and the unit displays brightness as cd/m2. So in eyeballing it, the screen is at about 44 fl (150 cd/m2). Per SMPTE I'd need to be 99 cd/m2, which still feels too dark. Sorry for the confusion!

Andrew Huebscher
Los Angeles, CA
 
Haven't had time to do more than just hook it up

Haven't had time to do more than just hook it up

Got my DreamColor but haven't had time to put it through its paces yet. Bummed to hear about the limited calibration toolset when feeding via HDMI. I should be able to provide some notes next week.
 
hyperfocal said:
... When I dial in the DreamColor where I like it, I actually lose the 7.5 pluge bar, but it's the only way to put the black level where it needs to be compared to a CRT. ...
Click to expand...

Andrew,

Thanks for the reply.

BTW, I'm not sure what you mean by "lose." Shouldn't the 7.5 bar be completely black and indistinguishable from the 3.5 bar?
 
Davio from Cine-Tal

Davio from Cine-Tal

Have anyone checked out the Davio from Cine-Tal (http://cinetal.com/products/davio_main.asp)? I just got back from IBC where it was set up with an HP DreamCast. It will take a Dual Link HD-SDI and convert it into HDMI 1.3. It also supports hardware 3D LUTS, which means that if you work with a LUT in Scratch you could offload it to this box - that's the theory anyway...

Great discussion!
 
Dreamcolour colour space calibration

Dreamcolour colour space calibration

I have the dreamcolour with the HP probe (actually an eye-one 2) re-badged as HP.

First things first - if you dive deep into the HP manual - you will see that the colourspace emulation functions only work on the HDMI, Displayport, and DVI inputs. BUT that is only if those inputs are fed an RGB signal. If your hardware is passing YCbCr, then no colourspace emulation can be performed. (HDMI and Displayport both support either RGB or YCbCr [sometimes erroneously called YUV])

This means that to have it be properly calibrated, you need to convert your HD-sdi signal to RGB via a hd-link or other device (and with an 8-bit conversion, you'll loose some fidelity, making a 10-bit link in this case more desirable)

The key to the HP display calibrator is not actually the probe (as stated above - it is an eye-one), it is the software that stores the conversion in the monitor's LUT, as opposed to generating an ICM profile that lives in the video-card's LUT (what most pc calibration software does) This can obviously only be done with software customized for the monitor.

Before calibration the monitor seemed neutral, but after it seems _very_ neutral. (a testament to the work that has gone into making that cheap piece of hardware accurate when compared with a Minolta spectro-photometer)

Just a side note about what Janne posted earlier:
Hey guys.

- 10 bit YCbCr 4:2:2 = 20 bit
- 8 bit RGB = 24 bit
- 10 bit RGB = 30 bit

10 bit SDI usually have YCbCr encoding, and uses only 2x10 bit channels, 10 bit for luma and 10bit for chroma. So 3x8 RGB bit is more.
Click to expand...

This is dangerous territory to get into guys. Colour resolution is not= to Luma resolution, which is what you're adding up in the above 'equation' You cannot compare 10-bit YCbCr to 8-bit RGB in terms of added bits. It is very hard to distinguish all three (4 if you also add 4:4:4 YCbCr) formats under even good viewing conditions with a properly adjusted monitor of any type. Where the value of 10-bit information lies is: 1 - rendering wide-gamut imagery (avoidance of banding), and 2 - for our use in post production/DI in pulling out and amplifying subtle detail.

When we see 4:2:2 imagery on a 10-bit or 8-bit display for example - we are still seeing 30-bits or 24 bits total. In case it is not clear above, a 4:2:2 10-bit signal transmits 10 bits for luma in pixel 1, 10, for Cb, and 10 for Cr, then for pixel 2 only transmits the 10 luma bits - Every other pixel simply has the same chroma information as the one to its left. but it may still have a different luma component. So we are introducing some inaccuracy, but to the human eye, it is virtually invisible (in fact the reason behind chroma sub-sampling is that the eye is much more sensitive to changes in luminance than chrominance [thus 10bits of luma is not the same as 10 bits of chroma]). Likewise with 8-bit versus 10-bit imagery, the main differrence lies in colour precision, not necessarily colour accuracy.

Cheers,
--
Ben Gervais
Digital Imaging Engineer / Freelance, Toronto
c 416-951-1980
h 416-789-9778
bengervais@gmail.com
 
hyperfocal said:
Doh! I double checked, and the unit displays brightness as cd/m2. So in eyeballing it, the screen is at about 44 fl (150 cd/m2). Per SMPTE I'd need to be 99 cd/m2, which still feels too dark. Sorry for the confusion!

Andrew Huebscher
Los Angeles, CA
Click to expand...

Well, to offer some context, I calibrate all the broadcast and viewing monitors in our faciltyto 27 ft/l using a mighty spendy Photo Research spectrophotometer and I can tell you that that is plenty bright for accurate viewing. It does take a bit of getting used to if you aren't accustomed to being around broadcast monitors and it can look a little dull. In my opinion, that's because most computer monitors and domestic tvs are ridiculously bright and people get used to it
 
bgervais said:
...
First things first - if you dive deep into the HP manual - you will see that the colourspace emulation functions only work on the HDMI, Displayport, and DVI inputs. BUT that is only if those inputs are fed an RGB signal. If your hardware is passing YCbCr, then no colourspace emulation can be performed. (HDMI and Displayport both support either RGB or YCbCr [sometimes erroneously called YUV])

This means that to have it be properly calibrated, you need to convert your HD-sdi signal to RGB via a hd-link or other device (and with an 8-bit conversion, you'll loose some fidelity, making a 10-bit link in this case more desirable)...
Click to expand...
I'm sure you've thought of this, but why not just send the DVI signal to the monitor?
 
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