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Powerbook 540c LCD, Can It Run In Grayscale Mode?
- Thread starter Paralel
- Start date
I should fire up my 540c , Switch it to greyscale and see how many shades of grey its capable of...
So the consensus is that you could install a "C" Screen in your 540, (with the proper corresponding display cable) leave it in grey scale, and just pretend its an authentic fully working 540 lol?
I can just picture you on the couch -Dark- (rocking back and forth) with one of those plastered half crazy grins, GreyScale LCD Glow on your face, saying weeeeeee I'v got a real grey scale Five-four-deeeee
With Blow apart parts to 520c's/540c's and Tunnel vision screens littered all over the floor.
lol
So the consensus is that you could install a "C" Screen in your 540, (with the proper corresponding display cable) leave it in grey scale, and just pretend its an authentic fully working 540 lol?
I can just picture you on the couch -Dark- (rocking back and forth) with one of those plastered half crazy grins, GreyScale LCD Glow on your face, saying weeeeeee I'v got a real grey scale Five-four-deeeee
With Blow apart parts to 520c's/540c's and Tunnel vision screens littered all over the floor.
lol
If you could, it would be appreciated.
Pretty much. I don't want to play screen roulette with the 540's being so flaky. Plus, 540c screens seem to be easier to come by. Although the one I found on eBay today, the seller is a jerk. He had the screen listed for $61, I made him an offer of $41, and he rejected the offer, no counter offer, removed the OBO from the listing and bumped the price to $95, and that's without the proper data cable. Good luck getting that for a used screen with no data cable, buddy.
Grayscale seems to top out at 256/8bit running under the Monitors Control Panel/Mac OS Drivers. I'm wondering if RadiusWare will drive one of their cards in grayscale @ 16bit?
Running the Portrait Display in 24bit color would be an interesting experiment as well.
Running the Portrait Display in 24bit color would be an interesting experiment as well.
RadiusWare is the proprietary Driver/Control Panel environment for Radius Video Cards and the name of the software for running the Radius Rocket in accelerator mode.
RGB video cards (with very rare exceptions) use six (original VGA) or eight (most things since the early 90's) bit D/A converters. Since a "shade of grey" is composed of an equal intensity of all three color elements the number of shades of gray you get is limited to the granularity of the D/A converters, IE, 8 bit, IE, "256 greys". (Monochrome CRT monitors use a single intensity feed connected to one of the three converters, while a color monitor displaying greys, again, needs to lock all three D/As together.) In principle you could get more shades of grey if instead of feeding a grayscale monitor conventionally you combined the outputs of all three D/As via a resistor network (or some other method) but you'd have to write a custom driver to make a sensible grayscale palette out of it.
One thing I'm mildly curious about is how many greys the Powerbook 540-era can actually display. I have an old TFT-screen'ed 486 laptop that has a very pretty display but it actually only has a 12 bit interface, which means it's only really capable of doing 16 shades of grey. (It looks fine under most circumstances because the video controller does some interpolation to keep things from getting "washed out" but you can reveal the truth by writing an appropriate BASIC program.)
That's a really good point. I wonder how many levels of grayscale it can actually display. It might say 256, but I wonder if it really is.
I know the panel is capable of displaying 15-bit color (5.5.5.0.1) or 16-bit color (5.6.5.0.0) at the reduced resolution of 640x400 on the Powerbook 540c. Don't know what that means for grayscale. If it is true 16-bit, and they use the green channel to display grayscale, it would be 64 shades of gray. 15-bits would be 32 shades of gray. If the panel is only 12-bits, like the one in your example, there would be only 16 shades of gray. Worst case scenario, if the 16-bit color is nothing but dithered 256 shades, then it would only be capable of displaying 8 shades of gray since 256 colors, using the green bits, only displays 8 shades.
I find this very interesting. For anyone that has a 540c, if you could check to see how it displays 256, 64, 32, 16, and 8 gray gradations, I'd be rather interested in the results. As soon as one can see obvious banding, dithering, etc... it has exceeded the ability of the screen to display that many shades.
I know the panel is capable of displaying 15-bit color (5.5.5.0.1) or 16-bit color (5.6.5.0.0) at the reduced resolution of 640x400 on the Powerbook 540c. Don't know what that means for grayscale. If it is true 16-bit, and they use the green channel to display grayscale, it would be 64 shades of gray. 15-bits would be 32 shades of gray. If the panel is only 12-bits, like the one in your example, there would be only 16 shades of gray. Worst case scenario, if the 16-bit color is nothing but dithered 256 shades, then it would only be capable of displaying 8 shades of gray since 256 colors, using the green bits, only displays 8 shades.
I find this very interesting. For anyone that has a 540c, if you could check to see how it displays 256, 64, 32, 16, and 8 gray gradations, I'd be rather interested in the results. As soon as one can see obvious banding, dithering, etc... it has exceeded the ability of the screen to display that many shades.
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I'd be pretty surprised if it can actually do a true according-to-Hoyle 256 grays. Until recently there were probably more laptops shipped with 18 bit (IE, six bit per channel, IE, "64 greys") LCDs than 24 bit displays. Someone even tried to sue Apple over it..
Not that it really matters. The human eye has to work to tell the difference between six and eight bit grey, and even 4 bit grey can look pretty good. (far better than 4 bit color.)
Not that it really matters. The human eye has to work to tell the difference between six and eight bit grey, and even 4 bit grey can look pretty good. (far better than 4 bit color.)
Very true. I'd almost forgotten about that. It is probably a 12-bit panel, making it no better than the Powerbook 520 at displaying grayscale, except it's active matrix.
I guess that makes the screens on the grayscale 540's that much more rare, displaying true 64 shades of gray. It must have been an expensive grayscale panel at the time.
If I can get my hands on a panel, it will be interesting to see if I can find a program that can give me the lowdown on the panels actual capabilities.
I guess that makes the screens on the grayscale 540's that much more rare, displaying true 64 shades of gray. It must have been an expensive grayscale panel at the time.
If I can get my hands on a panel, it will be interesting to see if I can find a program that can give me the lowdown on the panels actual capabilities.
520
Grayscale (16 Grays)
Passive
520c
Color (256 Colors)
Passive
540
Grayscale (16 Grays)
Active
540c
Color (256 Colors)
Active
http://support.apple.com/kb/TA21582?viewlocale=en_US&locale=en_US
Grayscale (16 Grays)
Passive
520c
Color (256 Colors)
Passive
540
Grayscale (16 Grays)
Active
540c
Color (256 Colors)
Active
http://support.apple.com/kb/TA21582?viewlocale=en_US&locale=en_US
Yeah, I wouldn't trust that page all that much. It also says the 540 is 16 shades of gray, when this says it isn't:
http://support.apple.com/kb/sp162
This page says the internal display of a 540c can do 16-bit @ 640x400:
http://support.apple.com/kb/sp163
http://support.apple.com/kb/sp162
This page says the internal display of a 540c can do 16-bit @ 640x400:
http://support.apple.com/kb/sp163
It was undoubtably expensive, but the color active matrix panels were even more expensive, requiring 3x as many pixels for the same resolution. I remember it was pretty much a given that an active matrix screen would have at least one dead/stuck pixel, usually 2 or 3. It was that or live with the ghosting and poor contrast of a passive matrix screen. We really have been spoiled by modern TFT panels with vivid, pristine displays and they're dirt cheap. You can buy a whole brand new laptop these days for a fraction the price of the TFT panel alone in the late 90s.
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