Dithering Report
Dithering Report
Dithering Report
By : Daniel Mulcahy
Island picture Normal: 101 KB
Island picture (32-Diffusion-Adapt) (GIF) : 202 KB
When the Picture is changed to a GIF, the size of the file seems to increase from what
it was as a jpeg.
I switched to the adaptive palette and used the diffusion dither for the picture to help
make the image still look good as I went down through the amount of colours in it.
I went thorugh 256 colours down to 8 bit colours and I thought that with with the diffusion
on, 32 bit colour was the best choice to still have the picture
at a decent quality.
Island picture (64-No Dither-Adapt) (GIF) : 212 KB
Next i tried the same picture again with the adaptive palette, but this time i used no dither at all...
You could notice easily the different in the background, even with 256 colours in it,
all due to no dither being on.
But i thought at 64 bit colour, the picture was still good enough quality.
Whats the best value?
Out of the 2 pictures showen...I think that the (64-No Dither-Adapt) is the best value for dithering you can get.
Even though its a slightly larger file, there is less of a difference from this picture and the actually normal picture at first.
(Also after changing the picture to a GIF file, I found that the size of the file is actually bigger then a JPEG)
Buliding (Normal) : 19.7 KB
(The best point to see the difference in these pictures is to look at the
right side of the second pillar on the left, and the steps up into the buliding)
Buliding (4-Diffusion-Adapt) : 7.34 KB
When i switched to the adaptive palette and used the diffusion dither, it was very easy to
still see a clear image as the picture is mainly black and white, since it was I was able
to cut from 256 colours down to only 4 bits of colour and still see almost the same image.
Building (8-No Dither-Adapt) : 9.52 KB
I then tried the picture again with the adaptive palette and with no dither and i cut still
cut down easily to 8 bits and a good image could still be seen.
This is however due to the fact that the picture is mainly made up of shades of black
and white.
Whats the best value?
From the 2 pictures above, I think that the (4-difussion-adapt) is the best value for dithering you can get
Since the picture is only different shades of black and white, it is not nesscerary to have so many different shades
Thats why you can make the picture a very small data size and still see it clearly, hardly noticing a difference
to have a decent picture, even with 4 bits in the picture, there is still good detail and you can see what the picture is still, easily
Does Dithering really help?
In my opinion dithering does help alot to cut back on the amount of bits and data in a
picture that is not really needed to have a good visible picture.
But there are times when dithering mighn't be the best as the picture could be very
detailed that you will need all the bits in it to keep it at a good decent quality.
Assignment
Map and Collage Assignment
