Film scanning and the UnSharp mask

Currently, I shoot film and then scan it before printing on my inkjet. I need to apply some Unsharp masking to make it sharper (my brain rebels against the illogic of what I just wrote ) but I do not know where to start.

Assuming the goal is to make a 8x10 or 9x13 print where is a good starting point for the Unsharp mask. If the goal was to display the image on one of our forums, would the Unsharp mask be set differently?

There are three boxes in the USM command:

The first is % - that one is just how heavy the effect
The next is radius - that relates to how course of a feature it should sharpen
The final one is threshold - that one determines how big of a tonal difference there has to be before sharpening will be applied.

Here are some general settings I use:

For WEB:
1st pass 150, 0.3, 2
2nd pass 100, 0.2, 2
3rd pass 100, 0.2, 2

For 4x6 to 5x7
1st pass 100, 0.5, 2
2nd pass 100, 0.3, 2

For 8x10 to 11x14
1st pass 100, .8, 2
2nd pass 100, .3, 2

For 13x19+
1st pass 100, 1, 2
2nd pass 100, .3, 2


These are generalities and sometimes I have to modify these significantly depending on the image and the effect I'm trying to achieve.

The term Unsharp Mask is answered in your other post.

hey E.J.,

that's a detailed reply. very helpful for us P/S neophytes, thank you. I know you don't shoot film any more, so are these the numbers you play with for your digital images, or your scanned slides?

Thanks.

Cheers

Carl

I use these numbers for both but I do employ a little bit of sharpening in the scanner for scanning slides so that the sharpness I start out with once I'm in PS is about the same wheter its scanned film of a digital file. I also apply some intial sharpening in Photoshop at 200, .3, 2 - this is the very first thing I do when bringing in a file. It is a very mild sharpening to try to counteract some of the sharpness lost due to scanning and due to the various filters on DSLR's.

I will just chip in and say that USM usually doesn't work very well for print sharpening if you have large areas of solid colors which usually contains some grain, especially in film. If you have a landscape image you rarely have to sharpen the sky, so use layer masks to do selective sharpening if possible. Usually I do High-Pass sharpening for 8x10 or larger prints. Check out luminous-landscape for some tips on this.

Sharpening is by far the most difficult thing I've tried to master in Photoshop, and still many images gives me headaches. Usually I find that large images intended for print are easily oversharpened, so be aware. Some trial and error is often neccessary to calibrate your eyes to this kind of sharpening. Print and Web are to different ballgames alltogether. Barry Haynes Photoshop Artistry is a good PS book for anyone making prints - Highly recommended!

sveingud wrote:I will just chip in and say that USM usually doesn't work very well for print sharpening if you have large areas of solid colors which usually contains some grain, especially in film.

Not sure I agree with this, by varying the threshold setting you can get good sharpening without sharpening the grain. If you are sharpening the grain, keep increasing the Threshold value until it stops doing that.

I agree with you, but I find that for most landscapes doing one high pass sharpening goes quiker (even faster if you make an action) than using the sliders in the USM dialog box, of course, high pass isn't ideal for every image either. My experience is that for 8x10 USM usually works just fine. When you move up to 13x19 and larger I find it increasingly difficult to use USM only, and use a combination of one high pass sharpening with some minor USM in critical areas. Using the threshold setting agressively may work for the sky, but sometimes gives poor results in other parts of the image, like a field of flowers with plenty of micro detail. The real clue however is to use layer masks to do selective sharpening in different areas of the image.

Sharpening using the history brush is another highly effective technique for selectivly sharpening areas. Changing the opacity (strength of application), and brush size and feathering as you apply lets you vary the effect. Combined with layer masks and/or selections this can prove extremely beneficial.
No one method is best for all images. Having many tools at your disposal and knowing when and how to apply them is key.

Best,

Chas

What is the advantage of making multiple USM passes instead of just one USM pass? I notice that some people recommend 3 or even 4 passes of the unsharp mask.

Quite often in Photoshop doing large changes in a big step will introduce more undesired artifacts than making multiple passes in smaller steps. Adobe even recommends this in their literature.

Excellent info.

EJ, I was of the assumption that USM is highly dependent of the file size in pixels. e.g. a picture with less pixels can handle less usm, just because of less resolution. These values of yours, do they apply for large files, like 2500x1500 pixels or so?

I'm also struggling with it and my usm results are better when I resize first and apply usm then, just because a subtle effect is sufficient.

I'll give it a go with your values. I've never dared to apply 3 runs...

Peter

The values I gave are ballpark numbers for the output size mentioned. By definition these imply different file sizes and there fore there are different values. But yes, your statement is true. I was trying to give a starting point. You will have to tweak these values for various conditions such as detail in the photo, sharpness of the picture to begin with, the effect you are trying to achieve, etc.