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Author Topic: More colour resolution  (Read 3708 times)

jliechty

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More colour resolution
« on: August 04, 2005, 04:59:19 pm »

I'm surprised to hear that Michael would have such an opinion of 16 bits per channel images. I thought he recommended them as being almost absolutely necessary for wide-gamut (ProPhoto RGB) work? Now I'm confused...

Anyway, the "problem" with those expensive medical video cards is that you have to have software that is capable of understanding that it can actually display that many more colors. Matrox's Parhelia cards, which cost a bit less and are capable of displaying color, come with a Photoshop plugin that lets you utilize the card's special 10 bits per channel color mode to view "more" of your 16 bit files. Unfortunately for those of us with LCDs, that feature is only of benefit to you if you have a CRT.
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jliechty

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More colour resolution
« Reply #1 on: August 04, 2005, 06:24:41 pm »

If I had to guess without looking, I would suspect that Ken Rockwell made that statement... His site is great if I need a good laugh, but unfortunately I fear he misleads many who don't know better.

Anyway, it's good to hear it again from the man himself.
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allan67

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More colour resolution
« Reply #2 on: August 05, 2005, 12:55:00 am »

Found this on Eizo site:
"The ColorEdge CG220 incorporates a powerful new EIZO-developed ASIC (Application Specific Integrated Circuit) with 14-bit color processing capability (16 times more accurate than 10-bit). This allows a larger number of grayscale increments, for grayscale rendering that is on a par with high-end CRT monitors. The result is a much greater degree of color detail, especially in dark areas and shadows."
And further down specs :"Display colors: 16.7 million from palette of 1.06 billion". It also supports Adobe RGB color space natively.
If you're able to part with money necessary to get it, this LCD can probably fit your requirements.
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avalon

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More colour resolution
« Reply #3 on: August 04, 2005, 03:11:19 pm »

I've seen Michael mention a few times on this website that it's pointless bragging about having 16bits of colour because your monitor won't be able to display it.

Because I've been playing with B&W shooting, a light bulb went off in my head - what about those dedicated grey-scale video cards and monitors for medical imaging?

Has anyone used any of these and if so, do they represent a tangible difference to normal monitors?

By way of example, Matrox have a video card targetted at medical imaging that does 1024 levels of grey (10 bit) at upto 2560x2048.  Of course this requires an appropriate monitor to view it with or else its all for naught.  2 more bits but 800 new "colours"

Has anyone ever looked into this type of equipment, which I expect to be pricey or viewed B&W digital photos taken on it?

And how does one fare when printing out such imagery - is it possible to obtain B&W printers to match?
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More colour resolution
« Reply #4 on: August 04, 2005, 06:19:36 pm »

Quote
I've seen Michael mention a few times on this website that it's pointless bragging about having 16bits of colour because your monitor won't be able to display it

Nonsense. I've never said that.

One should work in 16 bit mode at all times, if possible.

Michael
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avalon

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More colour resolution
« Reply #5 on: August 05, 2005, 12:27:38 am »

Quote
Quote
I've seen Michael mention a few times on this website that it's pointless bragging about having 16bits of colour because your monitor won't be able to display it

Nonsense. I've never said that.

One should work in 16 bit mode at all times, if possible.

Michael

My apologies for misquoting you, Michael.  I was drawing incorrect inferences from where you've discussed the limitations of output devices vs the data we work with.  I should have checked first before posting rather than relying on my brain.

Quote
Matrox's Parhelia cards, which cost a bit less and are capable of displaying color, come with a Photoshop plugin that lets you utilize the card's special 10 bits per channel color mode to view "more" of your 16 bit files. Unfortunately for those of us with LCDs, that feature is only of benefit to you if you have a CRT.

Doing a quick search, Matrox Parhelia cards no longer seem to be the only ones doing 10bit video DAC but maybe I'm not reading the marketting blurbs right.  I'm surrounded by cheap TFT screens, these days, so I can't claim to be able to research this myself.  Can anyone else comment on this?
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jliechty

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More colour resolution
« Reply #6 on: August 05, 2005, 01:42:44 am »

Quote
Found this on Eizo site:
"The ColorEdge CG220 incorporates a powerful new EIZO-developed ASIC (Application Specific Integrated Circuit) with 14-bit color processing capability (16 times more accurate than 10-bit). This allows a larger number of grayscale increments, for grayscale rendering that is on a par with high-end CRT monitors. The result is a much greater degree of color detail, especially in dark areas and shadows."
And further down specs :"Display colors: 16.7 million from palette of 1.06 billion". It also supports Adobe RGB color space natively.
If you're able to part with money necessary to get it, this LCD can probably fit your requirements.
I'm guessing on this as I don't own one, but (I presume) the CG220 can make the adjustments suggested by a hardware calibrator interally, instead of on the graphics card. To picture the advantage of this, imagine doing a few Curves and Levels manipulations on an 8 bit image, versus converting said image to 16 bits for the manipulations and then back to 8 bits after you're done. Both ways start and end with only 8 bits per channel, but one should give you a smoother histogram - and hence color gradients - at the end.

The point of all that is that Eizo's LCD will not actually display the other 2 bits worth of shades from a Matrox Parhelia. Yes, it will (should?) have better gradients than other LCDs, but you're still only putting 8 bits per channel in and getting 8 bits out.

Yes, other cards now have 10 bit DACs. These help when the card makes the calibration adjustments for a CRT in hardware (versus for an LCD where the adjustments are either made on the LCD a la Eizo or in software a la most others). However, Matrox is the only one I know of that offers a plugin to actually allow your software to take advantage of those 10 bits to display more than 256 distinct levels of intensity.
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