Sharpness?

[dennykyser]

Was wondering how I can get the SHARPEST pictures possible for web viewing. I see sometimes a picture that is so sharp its awsome and mine dont seem to be quite as sharp. I am mainly posting 400X600 pixel images and they have a reduced thumbnail so dont want the thumbnail to look bad either. Is there a technique do get this kind of sharpness. Thanks Denny

[maderito]

Images with a lot of color saturation, contrast, and isolation of foreground from background (e.g. with telephotos) often look very sharp even before applying sharpening techniques. These are well exposed and well edited images placed on the web for our enjoyment. The perception of sharpness is enhanced by the contrast between adjacent tones and colors.

For web sharpening:
After editing you image to perfection, downsizing it to web size viewing and then apply USM: radius=0.5, amount=100%, and threshold=0. This is needed to offset the softness that results from resizing. You can vary the USM parameters, but I think you'll find that the these work for most JPEG images. Don't oversharpen!! :x

[msvadi]

you have to reduce the size in several steps, applying some small amount of sharpening at each step. the unsharp mask filter is not very good for that purpose, the high-pass filter technique is better.

[dennykyser]

Could you describe that technique?

[evilenglishman]

dont sharpen the images. convert them to 800x600 and then use filter/sharpen - that should be enough.

[Scottes]

As I talked about in another thread here (http://photography-on-the.net/forum/showthread.php?t=35012) it depends on several things. How sharp is the image to begin with? Is it very detailed or not? Or only in some places? Sharp straight lines like buildings or random lines like fur?

Maderito's answer is generally good for Web images, though I like 150%, 0.3, 0 - this is also generally good for Web and will look fairly similar on most images. But sometimes you have to play with those numbers a bit depending on it's contents.

[dennykyser]

Have noticed something I hadnt thought about too, and you guys will rib me about it..


TRIPOD

I just noticed how much sharper my photos are that were taken in the studio. and one thing I do all the time in the studio is use my tripod. I bet that has something to do with it. I am sure the sharpening techniques will help too but like stated. has to be sharp to start with.

Thanks again.

[drisley]

I've done alot of testing on this, and I found 2 methods to be the best.

One good method is to use a program that uses the Lanzcos interpolation method for resizing. Breezebrowser does this, as well as irfanview.

For absolute best results, I use Photoshop, and do what msvadi says, resize in steps.
When increasing size with PS, stair interpolation in steps of about 10% works best. However, when downsizing, bicubic works best when you resize down in 50% intervals. So, I made an action to resize down by 50%, and I press it, and press it again, and keep doing so until I get one size bigger than I need. Then for the final step I enter the exact size I want. Then, I add some slight sharpening.
For the final step, if you have Photoshop CS, you can select Bicubic Sharp for the final stage, and then you dont have to add any additional sharpening.

You may just want to use Bicubic Sharp for each 50% resize, but I found it ends up with an image that is a little over sharpened. So again, I leave it until after the last stage.