Optimum resize/sharpen values Imagemagick

[UweB]

I played a bit with the resize/sharpen values of Imagemagick. Unfortunately i did not come to a usable conclusion for the settings... even with everchanging values and the preview i am not sure what looks and is theoretically best. I use images from prints and scanner and not from i digital camera....

for example my current settings:
resize 800x800, sharpen amount 1.4, threshold 0.02, radius 1, sigma 0.8
resize 1024x1024, sharpen amount 1.8, threshold 0.02, radius 1.2, sigma 1
resize 1280x1280, sharpen amount 2.4, threshold 0.01, radius 1.5, sigma 1
resize 1600x1600, sharpen amount 3.0, threshold 0.01, radius 1.8, sigma 1

for all sizes i use a compression ratio of 85%

Which other settings can generally be recommended? Are my settings logic or completely of the range?

[wkitty42]

FWIW: i don't know... i've never really understood sharpening and other processes like it... i can see the effects and in smaller pics like thumbs and microthumbs, it does make a bit of a difference... but in fullsized photos, i'm not sure why one would want to... doesn't the camera take an authentic representation of the view being shot?

my background is more left-brained (logical) than right-brained (artistic)... i've been involved in the computer industry for ~30 years... back in the heyday, we drew out our own circut boards and etched them ourselves... manual soldering of components and most definitely handdrawn circuts... i take photos of stuff i see that i want to document by some means... i like sunsets and sunrises but i take shots of a lot of different things... one "extreme" example would be the gutting and rebuilding of the engine in my '95 Gran Prix ;)

[UweB]

Hello wkitty42 !
i searched, i found, i read here: http://redskiesatnight.com/Articles/IMsharpen/ where every setting EE2 uses is explained. Only the relation of the settings to the size of the image is not explained...

Do you mean a Pontiac ?

[wkitty42]

Hello wkitty42 !
i searched, i found, i read here: http://redskiesatnight.com/Articles/IMsharpen/ where every setting EE2 uses is explained. Only the relation of the settings to the size of the image is not explained...
ahh, great! i'll try to drop by there and bookmark it for later studying...

Do you mean a Pontiac ?
yup!! drop by my site, if you like... it should be in my profile... it is self-hosted and finally on a pipe larger than 28k8 dialup (that the telco trashed from 56k)... at least it is now DSL and contrary to what everyone says, i'm 15+miles from the CO ;) ;) ;)