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View Full Version : 8 bit images, vs 24 bit


Neil
05-04-2003, 06:42 AM
I was looking through the Warcraft 3 wallpapers on blizzard, and they got em in 24 bit and 8 bit color. There is an obvious difference in file size too. I viewed both and i can see no difference. Are my eyes bad, or is something being limited by my hardware?
Someone willing to explain if they can actually see a difference?

elvis
05-04-2003, 08:53 AM
remember that a 24bit image can contain a maximum of 16777216 different colours in an image. that doesn't mean that every 24bit image has that many colours in it.

assuming an image has only a few thousand different colours, dithering it intelligently down to 256 colours (8-bit) isn't particularly hard, especially if some of those colours are very similar to their neighbour (as is the case with hand-drawn and coloured images, like the ones on blizzard.com).

i used a freeware utility called xnview (http://www.xnview.com/) to count the colours used, and for most of the images it's somewhere between 50k and 100k colours. again, this might seem like a lot, but the images are not photgraphic or skintone, which is where you see the most dithering when downscaling colour depths.

if you have photoshop, paintshop pro, or the GIMP, try playing around with colour settings in images, both hand drawn and photographic to see what i mean. sometimes reducing teh colour depth intelligently can really lower the size of your images for web use without rastically reducing their quality (ala heavy JPEG compression).

elvis
05-04-2003, 08:54 AM
just an aside: having said all of that, make sure you always work at a high colour depth if you are doing advanced blend and multi-layer images, otherwise you can end up with some ugly results when you run out of colours!

Neil
05-05-2003, 04:42 AM
Alright, i'm not too concerned with creating 24bit images, just curious more along the lines of why i see no difference.
but your first explanation makes sense.

DaForce
05-05-2003, 05:35 AM
what is your desktop color depth set to?

Neil
05-06-2003, 12:35 AM
32 bit.

DaForce
05-06-2003, 12:47 AM
ahh ok, well that rules out my theory.

I thought you may have been running a lower desktop color depth that way both images would look equally shite :-)

But it appears not.

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