Sharpening Question

[keoj]

The bane of my existence...how much is enough. Recently I dusted off an old action that I purchased several years ago (Intellisharpen from Fred Miranda - it a 14 levels of sharpening). It's a very nice action, works great. I'm going to print a couple of 35 mm frames at 12in x 18in based on a pretty good 4000ppi scanner. Is there a way that I can "preview" the amount of sharpening to get the correct look (tight edges, no halos, etc.) using a 72ppi monitor? How is this typically done? Is there any quasi intelligent sharpening program that sets a level based of the size of the end print. Appreciate any thoughts, I appreciate that it's far from an exact science, just looking for tips.

Regards,

keoj

[ocean7]

Not sure I can give you a lot of tips here, I always sharpen with the PS window at 50%. I can get results that are fine to my tastes, you would probably find what works best for you by trial and error. Take a sample print and try different sharpening parameters, printing all of them until you find the grail.

There's indeed a software that sharpens according to the output size. That saves me a lot of work as I only need to sharpen the master file and don't need to rework the image according to the output : Qimage http://www.ddisoftware.com/qimage/

It works great, but they need to work on their interface. It takes a while to get used to.

[keoj]

ocean7:

Okay 50% but at what radius and threshold? Thanks for the pointer to Qimage!!

keoj

[MikeCassidy]

Some things I was told:

UnSharpen at the image size you are going to use, I'm not talking about not viewer magnification.

Settings start with 200, .4, and 4.

You do two UnSharpens:

On the first use Fade Sharpen Mask and choosen Darken; on the second Unsharpen again use Fade Sharpen Mask but choose Lighten.

Also, you can select parts of the image and do different UnSharpening on them.

[ocean7]

Originally Posted by keoj

ocean7:

Okay 50% but at what radius and threshold? Thanks for the pointer to Qimage!!

keoj

You're welcome. The usual technique for the radius is to divide the output dpi by 200. For web display for instance 72dpi / 200 = 0.3 radius. For printing : 300dpi / 200 = 1.5 radius but this is just to start with, you really should experiment. Threshold to zero unless you have a noisy/grainy image. I really suggest you use CS2 smart sharpen.

[MikeCassidy]

"The usual technique for the radius is to divide the output dpi by 200. For web display for instance 72dpi / 200 = 0.3 radius. For printing : 300dpi / 200 = 1.5 radius but this is just to start with, you really should experiment. Threshold to zero unless you have a noisy/grainy image."

I find a threshold at zero gives a lot of sharpness to stuff you dont want sharp; but you are right you need to experiment with the settings with each image.

You also need to watch out for moire patterns in fences, corrugated metal sides, etc. when you sharpen, which is why I think it helps to do different sharping on different parts of the image.