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DPChallenge Forums >> Tips, Tricks, and Q&A >> second sharpening pass settings
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 02/24/2007 11:49:47 AM · #1
OK, a number of youse guys say that you re-sharpen a second time after you've resized your image for the challenges.

i've never done that, and i've been playing around with it and i just don't see a big benefit. i also like softer-focus images, though.

my question is, can you give me some examples of the settings you use when you do that second sharpening pass?

thank you.
 02/24/2007 12:04:06 PM · #2
Depending on how you resized...

500
0.2
0
 02/24/2007 12:21:50 PM · #3
It also depends on the image content, contrast, detail, etc.

There are three different techniques that I will use to sharpen after resizing.

for 640 pixel max:

USM: Amount 100-200%; Radius 0.3; Threshold 1 or 2 levels.

Smart Sharpen: Amount 40-80%; Radius 0.2; Remove: Lens Blur; More Accurate

High Pass (Advanced Editing Only): Duplicate BG layer, Set to Overlay, Filter>Other>High Pass: Radius 0.3-1 pixel

I will almost always will sharpen after resizing.

Hope this helps,
Lee
 02/24/2007 12:25:33 PM · #4
also, for challenge images, generally I will not sharpen at full-size. i think that compressing the already sharpened image creates an output image of lower quality than one sharpened at 640. Still, at 640 my image will stay as a 16-bit file so that i can utilize as much pixel information as possible. The very last step for me before submitting is to change it from 16- to 8-bit.

Lee
 02/24/2007 12:59:07 PM · #5
for challenges and portfolio i only sharpern AFTER resizing. settings @ 640 px:

between 50 % and 150 %
between 0,5 px and 1,5 px
0


02/24/2007 01:09:39 PM · #6
I resize the final product down to about 1200px, sharpen there, then resize again to 640.
 02/24/2007 01:10:50 PM · #7
I hit "Sharpen" once after I resize, then Edit / Fade Sharpen and fade back to about 30%. Works a charm for DPC size.
 02/24/2007 01:14:39 PM · #8
Unsharp mask is always my last step before saving the file at whatever size Ihave cropped it to.

I use anything from 50% - 300%
0.3
0

depending on the picture. For print size I always use 300% 0.3 0


02/24/2007 01:18:17 PM · #9
Can someone explain what the threshold level actually means please ?
02/24/2007 01:22:17 PM · #10
With my previous cam (Canon 10D) I used some moderate sharpening in RAW conversion, since the AA filter on that cam was rather strong. No other sharpening prior to resizing, and image remains in 16-bit/channel mode. After resizing, I apply final sharpening prior to 8-bit conversion. Settings dependent on file, but usually either:

Radius = 0.2
Amt = 200 to 500
Threshold = 2 to 5 (depending on noise level)

or:

Radius = 0.3
Amt = 100 to 250
Threshold = 2 to 5 (depending on noise level)

With my current camera, the RAW files most often need *no* sharpening on conversion, only applying sharpening after resizing. Also note that the algorithm and steps used in resizing have a huge impact on the amoutnt and type of post-resize sharpening required.

In some cases, I mask off areas that I don't want sharpened, or use the history brush at 33% opacity to partially roll back the sharpening. For a images where a soft-focus effect is desired, I run higher sharpening amount.
There are also some special cases, like night-sky images, that require some real dinking around to optimize the look for a 640px (or 720px as case may be) environment. I'm still developing new techniques to improve the final results.
 02/24/2007 01:27:15 PM · #11
Originally posted by kashi:
Can someone explain what the threshold level actually means please ?


"Threshold" defines the degree of contrast necessary for PS to consider something an "edge" and sharpen it. Try this: open an image up, magnify it to 100% on the screen, open up USM, and move the threshold slider all the way to the right, then back all the way to the left. See what's happening?

"Threshold" controls the subtlety of the edge-finding, "Amount" controls the degree of sharpening (contrast enhancement, basically) applied to the edges.

I think I have that right :-)

R.
 02/24/2007 01:32:09 PM · #12
To add to what Robert said, open an image that has visible noise (shot at high ISO, for instance) and call up the USM dialog. Set the following:

Radius = 0.3
Amount = 250
Threshold = 0

Now increase the threshold, and watch the noise. You'll find that as you increase the threshold, the high-contrast edges still get sharpened, but the lower-contrast noise does not. This is why I always recommend a non-zero threshold for most all images. Usually, 2 to 5 for threshold works well, unless there is substantial noise.
Sharpening after resizing has the advantage that noise, which is usually very high frequency, is averaged out by the resizing process. This makes the sharpening process less prone to make noise more visible.
 02/24/2007 02:46:54 PM · #13
Originally posted by muckpond:
OK, a number of youse guys say that you re-sharpen a second time after you've resized your image for the challenges.

i've never done that...

Many, if not most, photographers sharpen their images the FIRST time after croping and resizing their images.

That is because the amount of sharpening needed for an image resized for a 640 pixel DPC web graphic is a lot different than for one resized for a 20 X 30 sized print.
 02/24/2007 03:03:22 PM · #14
Originally posted by stdavidson:
Originally posted by muckpond:
OK, a number of youse guys say that you re-sharpen a second time after you've resized your image for the challenges.

i've never done that...

Many, if not most, photographers sharpen their images the FIRST time after croping and resizing their images.

That is because the amount of sharpening needed for an image resized for a 640 pixel DPC web graphic is a lot different than for one resized for a 20 X 30 sized print.


Are you not counting "bicubic sharper" during the resize?
 02/24/2007 03:20:32 PM · #15
Originally posted by Bear_Music:
Originally posted by kashi:
Can someone explain what the threshold level actually means please ?


"Threshold" defines the degree of contrast necessary for PS to consider something an "edge" and sharpen it. Try this: open an image up, magnify it to 100% on the screen, open up USM, and move the threshold slider all the way to the right, then back all the way to the left. See what's happening?

"Threshold" controls the subtlety of the edge-finding, "Amount" controls the degree of sharpening (contrast enhancement, basically) applied to the edges.

I think I have that right :-)

R.

That's basically right. The "Diameter" setting controls how far to each side of the edge boundary the effect extends.

I also only sharpen after resizing to entry-size.

I usually run a "contrast-enhancing" USM pass at 12-16%, 48-64 diameter, and a threshhold of 0. These seems to tweak the contrast and brighten the image in a subtly way which the Curves control seems to miss.

If the details still need some sharpening I run a more traditional set of USM settings: 66-88%, diameter of 0.6-1.3, and a threshold of 5 (or 7 if there are fleshtones or other smooth gradients). For a print image, I'd use the same settings, but a slightly larger diameter setting, since the file is so much biggr and has many more pixels to play with.
 02/24/2007 03:58:42 PM · #16
Originally posted by yanko:
Are you not counting "bicubic sharper" during the resize?


It's debatable whether using "bicubic sharper" is really sharpening. My experience says it is not, but it *does* greatly affect what's needed as far as post-resize sharpening. The number of steps used in resizing also impacts that. Given that you can choose to resize in a single step, or any number of discrete steps, and at each step use a different resampling algorithm, the possible combinations are unlimited. Some combinations will work better than others, but different strategies may be required for different images.
 02/24/2007 04:19:18 PM · #17
Originally posted by yanko:
... Are you not counting "bicubic sharper" during the resize?

Correct, I don't and that counts for "bicubic smoother" to. All bicubic is intended to do, I believe, is to more accurately render the image to the resize.
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