Digital Darkroom Assignment #17
cletus
Registered Users Posts: 1,930 Major grins
Assignment: Basic Sharpening
Rutt has written an outstanding introdcution to sharpening. To help encourage dgriners to take advantage of the tutorial, we're going to do a digital darkroom assignment on the basics of sharpening!
Take a look at rutt's tutorial and try to apply the techniques discussed to some of your images. As always, be sure to share the before & after images with the rest of us here in the assignement thread.
This will be a two-part assignment. DD Assignment #18 is going to be advanced sharpening and it will be accompanied with another tutorial provided by our resident sharpening expert - rutt!
Rutt has written an outstanding introdcution to sharpening. To help encourage dgriners to take advantage of the tutorial, we're going to do a digital darkroom assignment on the basics of sharpening!
Take a look at rutt's tutorial and try to apply the techniques discussed to some of your images. As always, be sure to share the before & after images with the rest of us here in the assignement thread.
This will be a two-part assignment. DD Assignment #18 is going to be advanced sharpening and it will be accompanied with another tutorial provided by our resident sharpening expert - rutt!
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Comments
The reason I like this method is that it's a lot easier to 'change' the amount of sharpening, without having to go back fiddle with the settings.
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
If you sharpen in a separate layer, there is no reason at all to change the "Amount" any lower than 500. Really the amount is just the opacity of the halos. But it still matters a lot to get the "Radius" and "Threshold" values right. So I like your suggestion.
We are right on the edge of a technique that Eric and I had reserved for the second, advanced assignment. I don't have a sense of where everyone is. Was the basic tutorial too basic? Should we move on? There is a lot more fun to be had with this topic than I have covered so far.
I guess I'll start on the advanced tutorial.
I'm not sure how much the average dgrinner thinks about sharpening.
I really should post before and after shots, as the Challenge requests. I guess sometimes I feel that the improvement is so subtle as to not stand up to a 'before and after.' But if that were the case, then there'd be no point in doing it.
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
OK, I do have a question. I read alot of your tutorial today and plan to print it out. I think I did find out what a "halo" was. I am not sure I would recognize it anywhere except in your car situation, though.
As an aside, one thing I will not do is sharpen a photo with any grain at all.
My question is: how can you tell a photo is oversharpened? What aspects of a photo make you think "over sharpened"?
I think of this as such a small question, but I don't have a problem with wanting more sharpening, as long as the photo is not a disaster of blur, and, as you pointed out, sharpening will not do much with that, I have used high pass, just to see, and it has helped, however.
I am trying very hard not to show any photos that have obvious flaws, are OOF, blown, etc. on the forum threads.
I did have a problem with the highlight/shadow when Andy said I should clean up my masking. I hadn't used a mask, but had used the highlight shadow, and he said it was that.
What am I looking for so I can "NOT" do it, or at least not present it on a thread.
What signs do I look for to see if a photograph is over sharpened?
Halos? I am not quite sure what a halo is?
What else?
If I know it looks oversharpened I can back up and fix it, before I show it to people. Right now I am having a lot of luck by "not using the USM much at all."
However I do use the highlight/shadow feature and the saturation feature, I am beginning to think that can mimic oversharpening, but I am not sure how to detect it when it does.
ginger
I just woke up, realized I wanted to ask this and threw the question together. There may have been a better way to ask it.
The edges of things draw attention to themselves. Spots etc. that shouldn't be prominent are suddenly very bright and visible. Things start looking a little too 'busy.'
If you'll notice, when you sharpen a pic it makes stuff stand-out that's otherwise kinda muted. For me, that's a big warning sign.
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
Next after RAW correction to exposure -.50, shadows 0, contrast +30, luminescense 10, noise reduction 35
This photo just did not seem to want much work except cleaning up, so I cleaned it and straightened the horizon. This was taken about 4 PM, plenty of sun. This one has not been sharpened.
This was sharpened at 200, radius 1.0, threshold 4.0 I usually only sharpen to about 84, but everyone else seemed to be sharpening more, so since I was doing this, I went further with the sharpening. (looks like another dark spot, will get it tomorrow)
Egrets on their half made nest, springtime in the southern coast.
photography by ginger
noisy photo. I have done alot with it in that I used RGB curves, I did not use the shadows or highlights, but in RAW I did raise the exposure to +0.70. In the Shadows/highlights of PS I used the midtone contrast to +38.
I think this is the one that is not sharpened:
And ordinarily I wouldn't have sharpened it, it is very noisy.
But I did sharpen it 200 USM
Now I suppose I should read your tutorial thoroughly.
ginger
At this size the effect of sharpening is subtle, but the left bird's eye and beak are sharper. Also the tree looks sharper. It would be a homerun to enhance the network of lacey wing feathers as well without oversharpening the tree bark and other vegatation. You can try a higer threshold and a larger radius. Did you follow my recipe and not just try to pull numbers out of a hat?
This will be a good image to revisit when we do advanced sharpening.
Do your homework! I wrote the tutorial just so people could actually understand what they are doing. There is no point to this assignment unless you gain understanding of the theory as well as practice of sharpening. I expect a post from you tomorrow that shows you have read it carefully. Questions are fine as long as they are not covered in the turorial or arrise from my bad writing.
Before
After
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
I did this photo, showing my thinking by showing the three parts that led up to it, according to the sharpening tutorial by Rutt. I also used a suggestion he gave someone on how to make the daffodils pop. It was such an easy thing to do, perhaps it only works on daffodils, but I did use it with this photo and a few others I did.
This photo is not sharpened at all.
This one takes sharpening to an extreme. I think, please correct me if I am wrong, that we are supposed to always go to the extreme, then pull back until the threshold, radius and amt are work to our liking and technically.
Starting with the threshold I started to correct the numbers here. I started with the threshold, took it down to the bottom where the grain was evident. I used a tombstone. I am a little confused on the 100% size. I just used the box in the sharpening BOX. I was not sure if I was supposed to blow the photo up 100%, too. Anyway, I could clearly see when the grain had disappeared to my satisfaction. That way I would not be sharpening grain which had been a consideration to me. I used the figure in Threshold where the grain was not visible to me. (I have figures here on two different photos, I did this last night, I can't tell which figures are for which photo, but I did know what I was doing)
Then I went to the radius to deal with the halos. I have trouble noticing halos. I went to the edge of the top of the tombstone. I could clearly see the white there. I looked for black halos, I could not notice any, not even around twigs or the writing. So I dealt with the photo with the white at the top of the tombstone. All the way up at 4.3 pixels, the white "halos" are quite apparent. I brought that down to 1.3 in one photo and 1.7 in the other.
I assume that some of the halo should still show, or there would be no sharpening, I am a bit confused on how much.
Perhaps someone could take a marker and point out some black halos for me. I don't even see them on Rutt's chain on his car.
Then I went to the amt which was at the top with the number 500%. I brought that down until the photo looked pleasing to me. In most cases that was a bit below 200. Maybe I should be using a higher number, there. I know one size does not fit all. I did about 5 or 6 of these photos last night, all using the same technique, not the same numbers.
This is what I finished with in this one:
______________
This was the first one I did. I was not happy with the blur in the flowers to my right, so I have not shown it, but it was first, I think the technique with the flowers worked and so did the sharpening. (These photographs were taken Sunday, 4/10.
This is from the RAW file I sent up to PS, obviously before sharpening.
The top one is oversharpened, and the bottom one is where I tried to get it right. ginger
I forgot to mention that I used Lab Curves for the color in the flowers. I suppose I deviated a tad from the daffodil example, a time or two, but it was the idea and the simplicity I liked.
I also was in Lab mode for the sharpening.
I forgot to mention threshold, I was in 15 in one and 20 in another. That may be high, I don't like noise unless I put it there. Smile. g
Sid, please share details. Only USM? If so what parameters? If not, what else did you do?
The improvement from sharpening in the first shot is really evident, especially on the rightmost tombstone. I'd like to see the before version of the second shot in order to access how well sharpening worked there.
Light halos are almost always easier to see than the dark ones. You can see both on the detail from Belive image. The mess on the granite in that shot has a lot of huge black halos in it. In Part 2, I'll show how to make both the black and white halos work independently. Let's leave the subject until then. It will be soon because I've decideded to break Part 2 up into bite sized chunks and this will be the first of them.
What I meant by working at 100% is to zoom in the main image window to 100% (it says on top). The reasons for using this window are: 1. it's usually bigger, and 2. with the L channel selected, you only get B&W in the sharpening dialog box but you can get full color in the main window if you make the other channels visible (as I showed in the tutorial.)
100/1/0, on a new layer, Opacity 28%.
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
I'm surprised we can see any effect at all. (Actually I couldn't, that's why I asked.) I'm also surprised that Threshold=0 didn't make a huge mess. Did you follow my recipe to arrive at these numbers?
Before:
After:
Lightness channel sharpend with USM:
Radius: 1.3
Threshold: 20
Catapultam habeo. Nisi pecuniam omnem mihi dabis, ad caput tuum saxum immane mittam
http://www.mcneel.com/users/jb/foghorn/ill_shut_up.au
Except for that threshold value. It's way aggresive. If you follow my recipe, you'll turn it up quite a bit and be able to sharpen a lot more with good results.
Just to make this super clear: more threshold implies less sharpening, so a value of 0 here is as aggresive as you can get. If you adjust this value upward, you'll find that you can use a lot larger value for amount and your sharpening will actually accomplish something visible without making a mess.
And what do you think Eric? How much did sharpeing this (nice) picture help it. At the size you posted, the difference is almost invisible to me, but maybe not at the size of your original. If you are going to resize for posting to the web, look at a before and after at the intended viewing size.
The idea is to take each parameter over the limit and then back down until you can stil see the effect, but not the reason. Yes, we must not see the trap door, but the lady also does have to vanish or there is no illusion.
You should be able to click on either image to get the original, or at least the size I sharpened at. On the larger size the sharpening makes a noticable difference and I think it looks very good. Best sharpening work I've ever done. Thanks, rutt!
I think that is an important point. I would put it in the tutorial somewhere, so if anyone deems that it should be in the Hall of Wisdom, this point would be there too. Even if it is there, like here, it is kind of hidden. For those of us who shudder as we/I raise my percentage amt much higher than usual, this makes it so much clearer as to why I can/should do that. My threshold is much higher than usual. I knew it related to grain, but I did not realize the full implications.
Thanks, Rutt.
ginger
Thanks, Ginger. It's been clear to me since our email that the "recipe" section of the tutorial could do with a rewrite. I like what I wrote to you better than what is in the tutorial and have been planning to incorporate it there. Until I do so, here is my rewritten recipe:
There are no universal right USM values that will work for every image. But there is a fairly simple 3 step procedure for finding good values for each particular image. Start by turning up all the values to very high levels: Amount: 500; Radius: 5; Threashold: 0. Zoom in on an area of interest to about 100%. Make sure you are in LAB and have the L channel selected, but all channels visible. Then:
- Tune the Threshold value by increasing until the noise in areas with no detail goes away. Usually for this will be a number between 15 and 30, but your mileage will vary dependend on ISO, raw conversion, light conditions, and subject matter. The threshold controls the when sharpening kicks in. Larger values here mean that sharpening happens only for more procounced transitions. So a low threshold value implies more sharpening. Set this value to 0 and you'll end up with a lot of sharpening where you don't want it, essentially sharpening noise and makeing it visible. Set it to 100 and you'll end up with no essentially no sharpening at all. I usually end up somewhere between 15 and 30.
- Tune the Radius value by decreasing it until the halos no longer overlap and obscure detail. The Radius value controls how wide the halos are. With Amount set to 500, the halos will be quite visible which makes this easier. You may need to look at more than one part of your shot to get this right. I find I often end up with numbers between .7 and 3. The right value is a dependent on both the resolution and subject matter of the image. The subject matter is important because halos will overlap when two transitons are close to each other. In the "Believe" shot, the grain on the tombstone has lots of very fine transitions: the speckles in the granite and so the radius I chose to make nice visible halos in the print really doesn't work for the granite. The halos overlap and make a mess.
- Tune the Amount value by decreasing it until halos are not actually visible, but the image still looks sharper than the original. Amount controls the opacity of the halos. At 500 they are close to completely opaque and at 0 they are invisible. Use the preview check box to switch back and forth between the sharpened version and the original. At this point you are trying to make the magic trick actually work. The illusion should be effective without the trap door being visible. I often find that values betwee 200 and 400 work here. Again, this is very dependent on the image being sharpened. It has a lot to do with the contrast between the light and dark areas in the transition, how light or dark the image is. If you use too small a number here, the sharpening will make no noticeable improvement and you might as well not have done it. Too large an amount and your viewers will see the sharpening and not your image.
IF YOU READ NOTHING ELSE IN THIS TUTORIAL: There are no right values for USM that will work for every image. Follow the procedure above for each image and you will find reasonable values. With practice, it only takes a minute or so per image.Usually it's the light halos that are visible and force smaller amounts. I'm going to cover a technique that allows for greater amount for the dark and halos in Part 2.
Here is the before (since we know Sid doesn't know how to sharpen yet, we can assume that for all pratical purposes it's not sharpened.)
Here it is after:
I used the technique from part 2 of my tutorial. I was working on the low res image sid posted, so the Radius values were much lower than one would use on a higher res image. I used Radius .5 which is pretty big at such a low resolution, but would be much too small for an 8MP original. Then I used 40% for the opacity of the Darken layer and 15% for the Lighten layer. If you've read part 2 carefully, you'll know that I left Amount at 500 during USM and used the opacity of the layers to do control the intensity of the halos.
This is what I posted at the beginning, when we first started this, and Rutt, you said this might be good for the second part, so I did this tonight. I can see a difference.
I started at the beginning here, because I knew I had not sharpened the first one.
The threshold was 58 (very noisy), the radius 2.7 and the amt was 500%
The opacity of the black halos was 34%
The opacity of the white halos was 18%
The originals are available.
http://gingerSnap.smugmug.com/gallery/481370/1/19762814
ginger
(I was a little confused on the more advanced method, but then it may be the early morning hour.)
After the sharpening. Below I can't get it any bigger, and I can't figure out why. Tired by now. It was a mess, though. Halos all over.
This was in the 1980s in another part of Magnolia Gardens from where I get my bird photos now. Fantastic place. (Oh, me on your right and Sara on your left) You know, Sara, with her family coming to live just two hours from me in a year. She was in high school here. Now she is 37 and has grade schoolers.
This is before it was sharpened:
And this is after using Rutt's second technique:
I think there is a marked improvement. There are still problems, remember children have trouble holding the flashlight under the covers and recording what they see at the same time, but I think this makes the image "there" for the discerning adult.
g Anyway, I entered it, and I hope they appreciate the work I went to to raise the number of entries. I love that book. It definitely has not stood the test of time, few people seem to have heard of it, and it reads in a way that is definitely not modern. It was written in the late 1800s, as a play, by Maurice Maeterlinck in Belgium.
Georgette Leblanc turned the play into a book for children. The version I have has been edited and arranged for schools of another time. Her version was named "The Children's Blue Bird". Maeterlinck called his play "The Blue Bird".
For the numbers, I didn't write them down, but I can say that the threshold was not high, the radius was about 1.7 (I intentionally left visible enough halos that I thought might enhance the contrast from one thing to another.) The percentage amount stayed at 500 til the end and is that now.
I've learned umpteen methods for selecting "what" to sharpen, but Rutt's (DM's) method actually was the first to really make sense to me what I'm really supposed to do with all three sliders. Most gave very specific guidelines for each slider. Now I know more of when to divert from the norm ...
Here's the photo that I played with. It's a injured Snowy Owl at a local zoo. I haven't done any crops or edits, other than a slight curve to improve the original contrast. Real life, real photos ...:D
Original
Rutt's single layer method:
I sharpened this at 100% looking at the face of the owl. As you can see, the tree trunk is way over sharpened. I continued playing around with this version by using a layer mask to take away some of the sharpening. Seemed to do the trick.
I was interested to see what the 2 layer sharpening method might do. This is my result:
Not an easy photo to do because of the very isolated white and dark tree trunk. I still masked one tiny halo on the tree
The one thing I can tell you, is that I did each photo at least a dozen times if I did them once! Talk about trial and error.:D
But I do like sharpening this way. It is obviously going to take me a lot of practice to get this skill to a level that I'm satisfied with.
Thanks Rutt for the tutorials.
Brad
www.digismile.ca