best scale/resize method?

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rogerKN

best scale/resize method?

Post by rogerKN »

what would be the best method to resize an image, from a quality point of view? i ran a search through this forum but couldn't find anything.

thank you

roger
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JohnFredC
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Post by JohnFredC »

When resampling (either up or down), my concern is always preserving very fine detail with a minimum of added aliasing.

After much testing, the best method for me has proven to be Lanczos.
John
rogerKN

Post by rogerKN »

thank you for this very clear and fast answer! let the resizing begin :)
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Drahken
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Post by Drahken »

It depends greatly on what exactly you're trying to achieve. Lanczos works well for enlarging most images. It also works well for reducing images without text. For reducing images with text, hanning works best (it keeps the text readable much more effectively than the other filters). If you're reducing a gif and plan to re-save it as a gif or 256 color png, don't use any filter (ie, use "nearest neighbor"). The results may not be as pretty, but using any filter on such an image will introduce blurring, which will in turn cause problems when you go to save the pic. (This is especially true with images that have transparency.)
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helmut
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Re: best scale/resize method?

Post by helmut »

rogerKN wrote:... i ran a search through this forum but couldn't find anything.
Hmm, perhaps not the right search keys. There's various topics, e.g.

- How to resize images with text (screenshots)
- How to prepare an image for the internet

And not to forget Lasse's sample pages:
- Sample page for resizing a normal image
- Sample page for resampling an image with text

Note that in the above tests the new Hanning filter is missing in the tests. Hanning might be a good choice for resampling images with text.
rogerKN

Post by rogerKN »

tnx drahken & helmut, and sorry about posting the thread while there were topics about this matter. thread may be deleted/closed now

tnx vor the help!