Sharpening slide film scans

[edward_karaa1]

Hi,

 

What are the best USM settings for 4000 DPI scans of 35mm velvia or provia

100? I have noticed that my usual routine (with DSLR files) using small radius

(0.3 to 0.5 pixels) tends to make grain too evident, so I probably would have

to use a larger radius but I'm worried about sharpening haloes with 1 pixel

radius upwards. Any advice would be greatly appreciated.

Thanks,

Edward

[jtk]

IMO the best bet is to preview the sharpening of each frame, treating them independently.

[roger_smith4]

Start with .6 and play with the amount (150-250) and per John's advice, don't just batch it.

 

I personally switched to two sharpening passes using Photokit sharpener, which does a decent job of sharpening edges without overemphasizing grain. You can do this manually as well.

[AaronFalkenberg]

I second PK sharpener. It is an amazing plug-in.

 

Barring that, anywhere between 0.4 and 0.6 at 150-250% is good for bringing out find detail in an image. To avoid bringing out the grain of similarily toned areas (backgorunds/out of focus areas) use a larger threshold of 2-4. This way, USM avoids sharpening any pixels with similar values in said threshold, but still sharpens fine detail (increasing micro edge contrast).

 

For images where there isn't much fine detail but large areas of tone and large edges (think of a macro leaf with droplets of water) you can increase the radius and threshold. This will leave the areas of smooth tone smooth, but sharpen the edges of the leaf and droplets.

 

Different subject matter requires different sharpening techniques.

[rob_landry]

Try using a program like Noise Ninja or Neat Image for grain (aliasing) reduction. Once noise reduction is applied, film scans sharpen up MUCH better in my experience. In fact Noise Ninja is part of my regular scan workflow; there really is no reason for not using it.

[pbizarro]

the amount of sharpening depends on the subject of the photo and the final printing size.

[edward_karaa1]

Thank you all for the replies.

 

Sorry I forgot to mention that this question is for the initial sharpening for the full resolution scan which look a little soft at full size. I do sharpen once more as the last step depending on the final output. I have Noise Ninja but was never happy with the results on film, it works great though for high ISO digital captures. I also happen to like the grain look when it's natural, but sharpened grain does look ugly. I will try some of the above advice and see which work best for me.

 

Any additional advice is certainly very welcome.

 

Thanks,

Edward

[robert_k1]

Evaluation of sharpness and noise on a monitor is an approximation of what will end up on prints (assuming prints are your final products). An image's magnification factor on a monitor plays an important role. An 100% magnification will often show excessive sharpening or noise, which may not be visible or offensive in prints. The ultimate evaluation is by looking at the prints.

[robert x]

edward - it is pretty standardly accepted "best practise" to do no sharpening until just

before you are ready to print - then you sharpen depending on print size etc. Ideally you

should keep your master original unsharpened [but with all adjustment layers and cleaning

of dust etc done], and just sharpen each time you print.

 

If you are getting noticable grain sharpening there are a couple of ways to deal with it.

One is to create a mask so that you are only sharpening areas that need sharpening.

Another I use sometimes if the image has a large area of sky or similar is to do the

sharpening, then set the sharpening step as "history state" then click on the step before

that, so the whole image goes back to being unsharpened. Then you go to your history

brush and simply paint in all the areas you want sharpening. (Or set history state to step

before and simply paint out the areas you don't want sharpened)

 

You can find tutorials about creating masks for sharpening on the web. [eg, here - http://

www.bythom.com/sharpening.htm - under "edge sharpening" should tell you (i didn't read

through this but you can find others easily enough)]

 

Robert