difference between 16 24 and 32 bit display
puck
someone more knowledgeable on this. i have been told that 16 bit is
the ideal for dvd playback and it seems to give smooth playback on my
pc with the agp card at 16 bit.
i also do some scanning, texts in ocr and small watercolour paintings
which inevitably end up being quite large (21mb the largest).
my scanner is capable of 48 bit scanning but i presume with the video
card only capable of 32 bit i can only see those scanned items in 32
bit?
in normal viewing of pictures from the moma collection (www.moma.org)
doesn't seem much different from 16 to 32 bit. if that is the case
what is the 32 bit required for?
i use adobe photoshop version 5 and paintshop pro (including the
animation programme). don't play games ever. the video card is matrox
g200 16mb sgram. monitor is generic (shinho badged but covered under a
matrox sticker!) 14 inch that does 60hz at 1024x768 and i think 70hz
at 800x600
any explanation or perhaps a website that explains would be most
appreciated.
regards
puck
www.clockswithbells.free-online.co.uk
some of the best new writing
from UK university students
Rodger Macfarlane
The number of bits per pixel defines the colour depth.
Raise the number two to the power of the number of bits and that will tell
you the number of colours which are available in the pallettefor each and
every pixel, or dot on the screen. For example, 1-bit is 2^1 = 2 colours, 8
bits is 2^8 = 256 colours, 16 bits is 2^16 = 65536 colours and 24 bits is
16,777,216 colours - generally regarded as the maximum number of colours
which can be resolved by the human eye.
Scanners have greater colour depth to give a massive colour range - 281
trillion. This gives a wider range of colours for the system to choose from
when scanning, though there's little point in going much above 24 bit.
All of these bits take up memory space, however. On a 640x480 VGA screen, a
256 colour picture will require 2,457,600 bits. At 8 bits per byte and 1024
bytes per kilobyte that works out to 300kb of memory to hold the screen
image. Take that up to 16bit and 1024x768 resolution and the amount of video
memory rises quickly to 1,536 kb or 1.5 megabytes.
By the time you've got up to 32 bit colour and 1024 x 768 resolution that
goes up to 3Mb. The reason why 3D graphics cards have such large amounts of
memory is that they have to hold more than one frame in memory in order to
improve speed.
When you're scanning, the resolution is much higher. Even a basic scanner
can manage 600 dots (or pixels) per inch. So even a 4 x 5 photo equates to
2400 x 3000 pixels. At 48 bit colour depth that works out to 42Mb!
A slightly higher resolution of 1200 dpi over an A4 (8 x 11 to make it
simple) page and you're up to 725 megabytes!
I hope this helps.
:o)
Take that to a
"puck" <hawsons...@cf.ac.uk> wrote in message
news:9hrc2todk0abuu4sb...@4ax.com...
Mark Tyndall
puck wrote:
>
> not being a technical person i thought i'd pose this question for
> someone more knowledgeable on this. i have been told that 16 bit is
> the ideal for dvd playback and it seems to give smooth playback on my
> pc with the agp card at 16 bit.
>
It could be that your graphics card has some hardware acceleration and your
dvd software can only use it when in 16-bit resolution.
> my scanner is capable of 48 bit scanning but i presume with the video
> card only capable of 32 bit i can only see those scanned items in 32
> bit?
>
You can actually only see them in 24-bit - 8 bits each for R,G and B. The
extra 8 bits in 32-bit are for the Alpha channel, which controls
transparency. This is currently only used in 3D games, so partially
transparent surfaces (and what they cover) can be drawn more easily.
> in normal viewing of pictures from the moma collection (www.moma.org)
> doesn't seem much different from 16 to 32 bit. if that is the case
> what is the 32 bit required for?
>
See above, but any difference will be dependent on:
The quality and format of the images on moma.
How well your graphics card handles 16-bit and 32-bit colour.
Monitor quality
Your eyes :-)
Mark..
--
I'm a blood-sucking fiend! Look at my outfit! -- Willow, BtVS
Stu@.
other depth, i believe most the accelerated features still work at others?
but performance wise you cant beat 16bit on the g200 CPU usage just
plummits..
Conor Turton
hawsons...@cf.ac.uk says...
> not being a technical person i thought i'd pose this question for
> someone more knowledgeable on this. i have been told that 16 bit is
> the ideal for dvd playback and it seems to give smooth playback on my
> pc with the agp card at 16 bit.
>
> which inevitably end up being quite large (21mb the largest).
>
> card only capable of 32 bit i can only see those scanned items in 32
> bit?
>
> doesn't seem much different from 16 to 32 bit. if that is the case
> what is the 32 bit required for?
>
> animation programme). don't play games ever. the video card is matrox
> g200 16mb sgram. monitor is generic (shinho badged but covered under a
> matrox sticker!) 14 inch that does 60hz at 1024x768 and i think 70hz
> at 800x600
>
> any explanation or perhaps a website that explains would be most
> appreciated.
>
and is worked out using binary maths.. i.e 8bit which is 2^8 gives 256
colours., 16 bit (2^16) gives 65536 etc etc . 32 bit 2^32=16.7
million) looks more richer but there is a limit to what the eye can
percieve.
--
_________________________
Conor Turton [MCP]
conor....@bigfoot.com
ICQ:31909763
_________________________
puck
stood up, raised ones hand and gleefully exclaimed:
thanks very much to everyone for the detailed explanation. i think i
understand a bit more about it that i did before.
kind regards
puck
Nick Hall
i.e 8bit which is 2^8 gives 256
> colours., 16 bit (2^16) gives 65536 etc etc . 32 bit 2^32=16.7
> million) looks more richer but there is a limit to what the eye can
> percieve.
<pedantic>
2^32 is 4294967296, 4.2 billion, it's 2^24 thats 16.7 million
</pedantic>
--
Nick
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