bad quality picture resizing. not a bug. just bad.

[soldierblue]

Hello,

I'm 29, and I am a standard user, not a digital artist or programmer. I did a resizing test for v3.5.10 and the result is disapointing to me. here is the result :

http://www.mediafire...3f6wy73w3k7hg1u .zip archive, 26 mB

the archive contains a high quality, 3200 x 5000, sharp complex colorfull .png original picture, and its resized versions (still png) using the main methods of PaintNet 3.5.10, Photoshop CS3 and XnView 1.98.8.

the archive contains a readme.txt with my opinion on this test. here is the content of this readme.txt :

PaintNet v3.5.10 bug report : resizing method too strong/sharp. really has to be fixed.

=======================

The original picture features a character whose clothes have some very fine pattern, sub-pixel size, and no bicubic and bilinear resizing methods I came across - Photoshop CS3, XnView 1.98.8, PaintNet 3.5.10 - succeeds in processing it without creating artifacts. And PaintNet 3.5.10 bilinear and bicubic give by far the worst results.

I watched carefully every picture in Xn View 1.98.8 (with high quality resizing turned On in its options/settings), in 100% 150% and 200% size, and here are the results :

NOTE : the most important pictures to look at are :

bilinear PaintNet 3510

bicubic PaintNet 3510

bicubic sharper Photoshop CS3

- PaintNet 3.5.10 bilinear and bicubic process the picture exactly the same way, just bilinear being a stronger/sharper version of the process.

Therefore, not to confuse the users, they might as well be called bilinear sharper and softer or bicubic sharper and softer.

- PaintNeT 3.5.10 bilinear and bicubic produce the objectively sharper result of all 3 softwares. Which is a good thing. That has to be kept.

- The problem is that the softer of the two method, PN 3510 bicubic, is already too sharp/strong to process very fine patterns, resulting in strong artifacts. too strong. making this type of picture impossible to process with PN 3510.

- Photoshop CS3 bicubic sharper is not has sharp as PN 3510 bicubic, but compensate by raising the contrast or something like that. the result is that we get much softer artifacts while having the feeling that the picture is sharper. maybe its sharpness is subjective, but our visual feeling of the picture is indeed what matters in the end. and the CS3 picture does feel a great deal sharper while having much softer artifacts.

conclusion

==========

these patterns are -very fine- and not that common, but just -fine- patterns do are very common, and it's already enough to produce (to me) artifacts that are too strong to be acceptable. personnaly, I will never use 3.5.10 to resize any pictures. it's CS3 all the way.

what should be done (if possible of course) :

soft result

===========

there is no soft processing in PN 3510. there must be one. like CS3 bicubic and bicubic-softer.

sharp result

============

what's the point of having a sharp image if it's full of artifacts ? the method used in bicubic CS3, less sharp with increased contrast, seems to me to be the way to go.

The best would be to have just 1 method, bicubic, with 2 sliders : 1 for sharpness and 1 for 'contrast', with presets for casual users. and everyone could get the result that suits them.

I don't want to use a big, heavy and pricy software like Photoshop just to resize pictures. this is a basic picture work that we all want to do with a small, light and free software like PaintNet.

So I really hope resizing will be fixed in future releases of PaintNet.

Big thanks to the creators of PaintNet for this simple, full featured and beautifull software

Edited September 15, 2012 by soldierblue