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Old Jun 16, 2007, 8:55 AM   #1
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I've been messing about for years with Paint Shop Pro and other packages, and only occasionally been really happy when I've finished resizing and sharpening an initially quite sharp 5, 6, or 7 Mpix image roughly to 800x600 or 640x480, for posting to Steve's Forums and elsewhere, putting on web pages, or emailing friends on dialup or with unfriendly email hosts.

Usually I've used PSP's 'Smart size' resizing option (it chooses a method by itself), followed by final sharpening by eye, viewed at the final size at 1:1 on my monitor, using unsharp masking with trial & error settings by eye. I do the same for prints, by viewing the image or part of it at actual final printed size, as measured with a ruler.

USM clearly has a vast range of possibilities. I may never have hit on a correct combination of "radius", "strength", & "clipping". The default are invariably too strong.

Just lately I've got promising results by downsizing with "Bilinear resample", followed by PSP's standardised 'Sharpen' instead.

What settings do the rest of you use?

I understand well that some images will need more sharpening than others, but what I'd like to develop is a standard technique for a quick first try, which I can then refine if necessary.

From Irfanview afficionados, I'd also be grateful for hints on a suitable setting for sharpening in that package, when generating a whole website of images with a couple of button presses using its brilliant "Save selected thumbs as HTML file" after batch resizing, renaming and sharpening all at once. At the moment I'm using 25 on a 0-100 scale, but if anyone knows a good average setting I'd like to hear it.

I might try emailing the author, Irfan Skiljan, to ask for advice. I need it anyway for another Irfanview feature, its editable templates, which I haven't managed yet to edit and still have them work. But I don't want to clog up his inbox when he's such a hero.

TIA for any responses,

Alan T
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Old Jun 16, 2007, 9:26 AM   #2
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I never go that high with sharpening (25 in Irfanview). But, that's probably just me, and it would depend on the original image (some cameras have more sharpening already applied compared to others). I probably use around 10 or 12 max (but, I don't like an image that appears oversharpened, so I'm very conservative with settings).

I'm not in Windows right this minute (I'm currently in Linux and prefer not to boot into my Windows partition if I don't have to). lol So, I can't check the Irfanview batch options right now.

But, USM was added to the available filters not long ago in Irfanview if you have the updated version and plugins installed. I know you can see it in the Effects Browser menus. But, I don't know if it's made it to anyplace else like the batch options. So, you may want to look into that, too.


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Old Jun 16, 2007, 10:08 AM   #3
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JimC wrote:
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USM was added to the available filters not long ago in Irfanview ....in the Effects Browser menus...don't know if it's made it to...batch options.
Thanks! Found it now. It's got just one parameter, from 0-10, so it'll be easy to experiment. Can't find it in batch modeas yet. Will report if it's there.

Once I knew it was there, I found it by searching under "sharpen" in Help, which I should have done before. I'd never have found it by accident as it's well-buried. As you say, "Image|Effects|Effect Browser|Unsharp Mask" (9th from top in v3.9).

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Old Jun 16, 2007, 11:02 AM   #4
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all i do it make a lower resolution version of my finished big photo

in photoshop i change resolution from 320dpi to 60 and that gives a file size of about 800k which i then host on my server

by hosting on my server im not governed by the limits that forums imply and the juggling u need to do to get a large size with low kilobytes

thats my totaly simple method :-)

gary
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Old Jun 16, 2007, 11:58 AM   #5
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Reanimator wrote:
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......in photoshop i change resolution from 320dpi to 60
This means that Photoshop is putting one pixel where 5.33 pixels stood. Some decision has to be taken over how to do that. A 'resampling' method must be chosen. Photoshop is choosing for you how to do it, transparently so far as the user is concerned, just as PSP's 'smart size' does for me.

PSP also offers the user the choice of 'bilinear resample', 'bicubic resample', and 'pixel resize'. Presumably these are all methods of averaging neighbouring pixels so as to get a representative result. I'm sure Photoshop has the same options, and more. I have an antique Photoshop 5LE that came with a scanner, but I've got to grips with very little of it.

Irfanview's resizing facilitiesoffer the choice of "Resample (better)" or not, in batch processing, and 7 different resampling filters plus "Resize (faster)" for individual images. It seems to methat some averaging of pixel valueswill be necessary, unless the new image size is a simple submultiple of the original. Maybe I'm just misunderstanding.

I'm just enquiring what others in this dedicated resizing forum recommend. I hope for some shortcuts to use when I'm dissatisified with what the automatic defaults give me so I can avoid trying out a very large number of combinations of settings.

I notice from your results Gary, that your simple method works very well indeed for you, however it does it!

Alan


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Old Jun 16, 2007, 12:05 PM   #6
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digiKam 0.9.2

Use the "refocus" option you'll find under sharpen with the default settings with the default resizing options under batch operations. It does a good job without the complications you sometimes see with other sharpening options (and it's got multiple ways to sharpen, including USM).

Of course, you'll need to use Linux. ;-) digiKam is Open Source and has lots of neat features.

http://www.digikam.org/?q=about/features09x


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Old Jun 16, 2007, 1:00 PM   #7
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alan

i let photoshop resample downwards in its bicubic mode

any other stuff like sharpening and levels adjustments etc are done at full size, my shots are aimed at printing big, panoramics are 3 foot long and like to print standard shots art 20x30 inch

guess am just lucky with the way i do it

have u tried doing all your editing and sharpening befor you reduce size??

if u want me to try my way on a pic just to see i will do, maybe post results here to see how they compare to help u figure out whats best, it could just be that photoshop is very good at it, hence its price?


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