Re: Shrinking a picture --- and it becomes blur !!

mark.thomas.7@[EMAIL PROTECTED]
 wrote:
> 
> As advised, rendering to the size you want may be the best way.
> 
That's the best approach...

> Or try the "Lanczos" algorithm - eg in Irfanview.  Also, downsizing in
> steps may work better, in other words, try reducing in steps of say
> 20% (or even less), and then experiment with light sharpening (USM) at
> each step - Irfanview has this function built in, but I can usually do
> a little better manually.  I've found what works for some images,
> doesn't work as well for others.. and I've never experimented with
> rendered images, so all this may be useless...  (O:
> 
Can you explain, why there should be any advantage in scaling down an 
image in smaller steps? I've read this several times by now and can just 
say that this seems like some quite big bull**** to me.
Maybe you can prove me wrong by supplying three images:
- original
- downsized in one step
- downsized in several steps
and the exact steps you used to get this result.

The logic behind downsizing in several stps is not clear to me. you 
downsize by 20%... so you lose some information and the computer has to 
interpolate ("guess" some values). After this you use this guessed 
values to further shrink the image... and this should lead to better 
results (and more detail) than downsizing in one step?
If this was true, I'd fire ALL (every single one) developer of the 
scaling-procedures in every graphics program!
And think a bit further: IF there was an advantage in scaling down in 
steps, the would be such a function built in the graphics-applications.

Ok, you can prove me wrong. Good luck! Mathematics and 
Information-Theory is normally hard to beat!


> The best you can hope for is one/two-pixel sharpness, so maybe you are
> expecting too much?

That's for sure. Maybe he would be happiest with the cheapest 
scaling-procedure available. No interpolation at all (i.e. nearest 
neighbor). This will give him the sharpest image possible.

Marco

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