Sharpening for Finely Detailed High Frequency Images

pathfinder · April 24, 2005

Sharpening for simple graphic images is easily accomplished. Sharpening high frequency images can be more challenging.
I posted some Canadian geese BIFs and background shots in the Nature thread last week-
http://dgrin.com/showthread.php?t=9906&page=1 - and Rutt felt that the first image of spring trees was oversharpened. I suggested that a discussion of the sharpening of this image might be interesting and informative and that rutt might teach me a new trick or two. We decided jointly to move the discussion here.

I reviewed the edit history of this image and found the settings I used for sharpening this image. The original image was shot at f9, 1/500th with a 300mm + 2x with a 1DsMkll.
The image was converted from RAW in ARC, and then brought into PS as a 16bit image in the ProPhoto color space. After color balancing and setting my curves and minimal cropping, I moved the image to Lab and created a duplicate with Ctrl-J. I did not flatten the images when converting. I then shifted to the lightness channel and used the USM on the upper layer. My settings for USM were 500%, 1.2 pixels, amount 26. (I followed the sharpening in real time by looking at the image at 100% size on my monitor watching carefully for light halos - which should be minimal in the lightness channel.) I then blended the sharpened layer with the background layer at a blend of 51% in the normal blending mode.

The image was then flattened, shifted to the 8 bit sRGB color space, and saved as a jpg for loading to smugmug where the image is hosted. I believe it is a quality level 10 jpg.

The original size file can found here on smugmug -- It will not be found be just going to my smugmug page - you will need the link below.

http://pathfinder.smugmug.com/gallery/498787

It is pw protected - pw will be "rutt". Inidividuals wanting to follow the discussion rutt and I plan, can download the image and follow along as we try to improve on the sharpening workflow.

I am looking forward to seeing what can be done with this image to improve it in any way. John, we might also include the High Pass filter as this is used for high frequency images sometimes also.

gus · April 24, 2005

Ta Daaarrrrrrrrrrrr !!

rutt · April 24, 2005

Since you have a new camera, Jim, you should make sure that ACR isn't sharpening. You have to set something like "sharpen preview only". I'm sure you have done that, but I think the camera default is to sharpen and you do have a new camera. Double sharpening will be bad.

pathfinder · April 25, 2005

rutt wrote:

Since you have a new camera, Jim, you should make sure that ACR isn't sharpening. You have to set something like "sharpen preview only". I'm sure you have done that, but I think the camera default is to sharpen and you do have a new camera. Double sharpening will be bad.

I have left the camera setting with minimal sharpening - Does the sharpening affect the RAW image or just the jpgs? Seems to me that it only affects the jpgs, but I could be wrong. I'll take a gander at the manual again. I do not see oversharpening in my images generally - they remind me very much of the soft images that the 1DMkll creates. Seem very similar, only bigger. Bigger.

pathfinder · April 25, 2005

Humungus wrote:

Ta Daaarrrrrrrrrrrr !!

OK 'gus - I see you got the file - now - what, if anything did you do to it?

I actually can't see much difference between your image and mine on my monitor. Do I need my eyes examined??

I guess yours is slightly softer than mine perhaps.

gus · April 25, 2005

I did all i could do...i cheated & ran it through a plugin/action i have which does 42 different sharpening things to the photo (i did count them & it was about 42).

Does a great job though.

Here is the original of yours after i ran it through...look ok to you ?

Ok...that wont work then try this

.

pathfinder · April 25, 2005

Humungus wrote:

I did all i could do...i cheated & ran it through a plugin/action i have which does 42 different sharpening things to the photo (i did count them & it was about 42).

Does a great job though.

Here is the original of yours after i ran it through...look ok to you ?

Ok...that wont work then try this
.

'Gus, When I compare your image at 100% on my monitor and my original psd file I do not see very much difference at all. My image has slightly more pixels at 255,255,255 than yours - I noticed this by finding the threshold values in the adjustment layer tools area.

But I do not really see haloes in either image.<img src="https://us.v-cdn.net/6029383/emoji/ne_nau.gif" border="0" alt="" > Lets see what rutt says tomorrow.

gus · April 25, 2005

Are you saying my action does not appear to work or that it does the same as your manual sharpening ?

I seriously wouldnt have a clue...

pathfinder · April 25, 2005

Humungus wrote:

Are you saying my action does not appear to work or that it does the same as your manual sharpening ?

I seriously wouldnt have a clue...

No I was not saying tha it didn't work just that there is not much visible difference between your jpg and mine

gus · April 25, 2005

pathfinder wrote:

No I was not saying tha it didn't work just that there is not much visible difference between your jpg and mine

So should i continue on my path of ignorance & keep using it ?

Does an ok job for a 'press here for idiots sharpening' i mean.

Mitch · April 25, 2005

I've been told that I lean toward under sharpening so I am looking forward to picking up a few pointers. From the image in the link to the first post I can't tell that it is over sharpened. I did grab the file from your site, it was a little soft. Ran it through FM's intellisharpen II. Ran it through rather hi. 94 sharpening and 20 fine detail.

Here is link to it Sharpened

Oops maybe should have added a link to the gallery
hope this works.

I will remove this image at the end of this thread or sooner if asked.

Mitch

rutt · April 25, 2005

pathfinder wrote:

I have left the camera setting with minimal sharpening - Does the sharpening affect the RAW image or just the jpgs? Seems to me that it only affects the jpgs, but I could be wrong. I'll take a gander at the manual again. I do not see oversharpening in my images generally - they remind me very much of the soft images that the 1DMkll creates. Seem very similar, only bigger. Bigger.

It's not a camera setting I'm talking about. It's the ACR settings you are using. The ACR default is to sharpen on conversion. You have to disable that if you want to sharpen yourself. I believe that this setting is camera relative. When you start using a new camera, you'll get "camera defaults". Look on the detai tab of ACR and make sure the sharpening slider says "preview only". If not, change the camea default by following the little button to the right of the "Settings" pulldown. Then reset the camera defaults.

I'm thinking it's possible you sharpened twice, once in the camera and once in PS.

Anyway, I did look at the image. It does look soft to me. This kind of tangle of vegetation presents challenges to both focus and sharpening. What is the center of focus of this image?

pathfinder · April 25, 2005

rutt wrote:

It's not a camera setting I'm talking about. It's the ACR settings you are using. The ACR default is to sharpen on conversion. You have to disable that if you want to sharpen yourself. I believe that this setting is camera relative. When you start using a new camera, you'll get "camera defaults". Look on the detai tab of ACR and make sure the sharpening slider says "preview only". If not, change the camea default by following the little button to the right of the "Settings" pulldown. Then reset the camera defaults.

You are talking about the Preferences setting in the Camera Default - advanced settings. I have changed that to sharpen preview only. But I always slid the Sharpness slider to the left - but now it says preview only. OK - maybe it was sharpening twice as you said. Not anymore though. Need to do this for my 20D also then.

I'm thinking it's possible you sharpened twice, once in the camera and once in PS.

Anyway, I did look at the image. It does look soft to me. This kind of tangle of vegetation presents challenges to both focus and sharpening. What is the center of focus of this image?

As I looked at the image I think the focus was more on the larger trees behind the purple vegetation - but high frequency images like this can be challenging in that regard also, as I did not choose my AF point for this image since the whole central set of AF points - 6 or 8 - lit up.

Give me a day or so John, and I'll start again with the RAW file that is not sharpened by ARC and see what happens. I'll tyr to get the file into the same gallery as earlier by Wednesday.

pathfinder · April 25, 2005

Mitch wrote:

I've been told that I lean toward under sharpening so I am looking forward to picking up a few pointers. From the image in the link to the first post I can't tell that it is over sharpened. I did grab the file from your site, it was a little soft. Ran it through FM's intellisharpen II. Ran it through rather hi. 94 sharpening and 20 fine detail.

Here is link to it Sharpened

Oops maybe should have added a link to the gallery
hope this works.

I will remove this image at the end of this thread or sooner if asked.

Mitch

Very nice looking front page for yor gallery Mitch, but I can't get past the password. I am looking forward to seeing your result, but the link did not work for me.

rutt · April 25, 2005

BTW, I don't think this puts an end to this discussion. It's a good topic. I think it's especially interesting of you place a subject in the foreground which you especially want to sharpen. A person, building, or animal, perhaps. Sharpening that enough and not overdoing the shrubbery has been a problem for me. I wrote to Dan Margulis about this and his answer was:

If you feel that they don't, then you're saying that the picture wasn't shot
correctly for your purposes. Sharpening a part of an image locally is as much
a move away from the art as it would be to select the area and change its
color.

If you really think that you have to divide the image in half, fine, but
unsharp masking is a really clumsy tool to fix the problem. If you must, you
should select the background and reduce its contrast, or desaturate it, or if
you're in CMYK you can blur its black. If you do these things subtly enough
people won't get the impression that you cut the foreground object out and
pasted it in.

Once you've degraded the background slightly then global sharpening may work
better.

Mitch · April 25, 2005

pathfinder wrote:

Very nice looking front page for yor gallery Mitch, but I can't get past the password. I am looking forward to seeing your result, but the link did not work for me.

Oops sorry I did pasword protect it is "rutt"

Mitch · April 26, 2005

I read rutt's first thread on sharping and decided to give it a try. Then I got to wondering how it compaired to the other methods I use. FM-Intellisharpen I, FM Intellisharpen II, and a method something like SHARPENING II by rutt. Sharpening two layers setting one to DARKEN and the other to LIGHTEN but I work in RGB. I put those two layers in a layer set. Now I can adjust each layer by itself then if I need to adjust the sharpening set.

Just incase someone wants to grab the file here is the URL

My next project is to read and understand SHARPENING II by rutt.:D

Let me know what you think, all comments are welcome.

Thanks for looking.

Mitch

rutt · April 26, 2005

Thanks, Mitch, I was going to get around to writing something about FM sharpening, and hope still to do so.

There is good reason to sharpen the L channel, even if you then go to RGB for blending (that's essentiallly Part 2 of my tutorial.) Sharpening on the composite RGB channel can produce unwanted color artifacts; in fact, it nearly always does. They may not be visible or bother you, but it's worth the trip to LAB to avoid the possibility. Once you are done, you move back to RGB and proceed as before.

Mitch · April 26, 2005

Hi rutt,

I was just sitting here looking at the 5 slices. Of the two FM plugins 2 looks sharper than 1.

Now I may have done something wrong in the sharpening (let's say more than likely) but if you look at the unsharpened slice you will see color in the pestals (atleast that is what I think they are called). The two FM's held the color pretty well. The darken/lighten and the Lsharpen has lost the color, but both of these look the sharpest to me.

I've read you sharpening 2 post and have some questions, but I will hold them until I get the chance to try it. Just in case hands on answers them.:D

Oh and I also posted the full picture so anyone can download it and show me up with their sharpening skills.

Here is the address again.

Mitch

rutt · April 27, 2005

Mitch, I'm not sure I know which part of the image the "pestal" is. I can see see some light halos in the curly thing middle left, especially in the L-sharpen iamge. Probably this image needs a pretty small radius.

rutt · April 27, 2005

rutt wrote:

Mitch, I'm not sure I know which part of the image the "pestal" is. I can see see some light halos in the curly thing middle left, especially in the L-sharpen iamge. Probably this image needs a pretty small radius.

Oh, I see it now. It's the "hairs" sticking up. What you are seeing is light halos, for sure. This is happening because the radius is too large and the amount is too much for the light halos. They're wide enough to obscure the nearby "pestals" and solid enough to dull the perception of color. If you do Part 2 sharpening (a lot like your light/dark sharpening) carefully, you will address this issue. If you still see this desaturation, you can use LAB curves on the lighten layer to add a little color to the light halos. (This should be a last resort.)

pathfinder · April 27, 2005

pathfinder wrote:

You are talking about the Preferences setting in the Camera Default - advanced settings. I have changed that to sharpen preview only. But I always slid the Sharpness slider to the left - but now it says preview only. OK - maybe it was sharpening twice as you said. Not anymore though.

Give me a day or so John, and I'll start again with the RAW file that is not sharpened by ARC and see what happens. I'll tyr to get the file into the same gallery as earlier by Wednesday.

John, I tried to go back to the original RAW file and cannot find it. I shoot so many images on some of these days out, that I don't keep the RAW files after I have edited the images and I suspect that I deleted the original RAW file for this image as it was not a favorite of mine anyway. So I can't go back and and do another RAW conversoin in ARC.

Sharpening for Finely Detailed High Frequency Images

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