[Image-SIG] Placing colored pixels next to each other

[Steve Lianoglou]

Hi folks,

I'm quite new with PIL and I'm trying to do something simple but I'm  
having a hard time getting this to work the way I want.

What I want to do is place two different colored pixels next to each  
other w/o one trampling over the other. I'm not quite sure what's  
happening, or what to call it, maybe antialiasing, but lets say I  
want to place a green pixel at 0,0.

Just setting one pixel to red doesn't make a red pixel at all, it's  
rather grey. If I make a box (say 5x5) it's a bit better, but the  
color isn't confined to the 3x3 box anymore .. there's a "splatter"  
of coloring (of lower intensity) in the neighborhood of my red box.

That's probably desirable in most cases, but I'm looking for exact  
color hits ... eventually what I'd like is to have red and green  
pixels next to each other w/o them interfering with their neighbors.

I'm trying to visualize a 6000x200 matrix (in this case a microarray)  
where each pixel would represent an index of the matrix .. the  
different colors in each pixel would represent something else.

Even if I make the image 18000x600 to do 3x3 pixels for each "index",  
the red and greens still fight with eachother and I get a nice grey  
smudge for an image.

Is there another approach I should be taking, or a setting I can turn  
off so this doesn't happen?

Oh ... I'm using recently checked out svn version of PIL (thanks for  
the numpy integration, btw) and am setting the mode of the image to  
be RGB and RGBA (I'd like transparency to, eventually), for the record.

Lastly, I apologize if I'm missing something obvious, looked through  
the docs located at http://www.pythonware.com/library/pil/handbook/ 
index.htm but can't seem to make sense of it for what I need to do.

Thanks,
-steve