Difference between revisions of "GIMP/C2/Selective-Sharpening/English-timed"

!Time

!Narration

|Welcome to the spoken tutorial of Meet The Gimp.

|Today I would like to teach about selective sharpening.

|00:30

|But when you do it yourself by using the GIMP you can control the sharpening, and in today’s tutorial I will show you how to do it.

|Let’s have a look at this image here. In this image the wire mesh in the background is the big unsharped area and the flower here is a bit sharpened. So I want to sharpen the flower a bit more and keep the background as it is.

|But first I want to show you why I don’t want  to sharpen the background. Its unsharped now and little bit of sharpening should not do any harm so I select the sharpen tool by clicking on the Filters in the tool bar and pull the sharpness slider up and you can see that the originality of background is destroyed but if you look here and I take the sharpen tool here, And when I pull the slider to the extreme value the picture dissolve.

|So sharpening unsharped areas or areas which are filled with color and no details, spoils the image and this happens because the colours in the image which needs no sharpening gets sharpened. So I’ll tell you the method of selectively sharpening which does not destroy the image.

|To do selective sharpening I will work with layers.

|This time I simply make a copy of the background layer and call it sharpen.

|Now I add a layer mask to the sharpen layer and I select the gray scale copy of the layer as the layer mask and click on add option and you see no changes has happened because the layer mode is normal but when I de-select the original back ground layer you can see that only the bright parts in the image are visible .

|And if you remember white in the layer mask reveals the bright parts and black hides and you can see here most of the layer mask is dark so they are hidden and only the bright here is visible.

|Now when I use the sharpening algorithm on the layer mask only the flower will be sharpened. And I also want to sharpen the leaf part. And in the sharpen image I don’t want to have the white areas in the flower and I want only the fine details.

|To do that I use the 2nd filter and this is Edge Detect. This is the algorithm that helps for looking in the image for the edges between bright and dull part and enhances them by making white line there. You can leave these options here as they are because there is not much differences between these algorithms but I increase the value of amount to 4 and look in the preview. You can see here the background has a little bit of structure in it and in the brighter part there are thicker white lines. I click on OK and wait for the algorithm to apply it to the image.

|It works and now I get a white painting of all the edges. I zoom into the image by pressing 1 and you can see here all the bright parts now have a white border and white line and all the other areas are nearly black.

|When I switch off the layer mask and and the background layer you can see only the edge of the flower i.e the brighter part is visible.

|Now I can sharpen the edge of the flower without affecting the colours in the background and the colour of the flower. But this would give a strange effect like a sharp line in a muddy background and to avoid that I use another filter on this layer called blur.

|I select the layer mask and use gaussian blur to smash this white line a bit, and I increase some value in horizontal blur radius say upto 8 and click on ok.

|Wait for the completion of the filter and now you can see that the edge of the flower is a bit more softer and I think I need a bit more contrast in the image so I select the curve tool and click into the image to get the curves and I pull the curve a bit down to get the dark darker and pull the bright part up and get the white whiter.

|Click on Ok and now I have thick white lines where there is a need for sharpening and black part where no sharpening should be done. I could work on the black part but it’ll show no effect.

|Now I disable the layer mask here and press Shift + Ctrl + E to look at the whole image

|Now you know Shift + Ctrl + E to look at the whole image. When I disable the original back ground layer I can see nearly nothing of the image.

| Let me explain you what’s happening there by adding a new layer with a white layer fill type and press ok. Now you see the areas that needs to be sharpened.

|Now let’s sharpen this image, I click on filters in the tool bar and enhance and select sharpen.

|08:24

|Go to the area of the flower where sharpening is to be done and see to it the sharpen layer is selected because there is nothing to sharpen in the white layer.

|So select sharpen layer then filter and re-show sharpen and here you see the flower and now I can pull the sharpness slider up till I get a good sharpened image and then press on ok and wait for the algorithm to work.

|Let switch this white layer off and see the full image.

|Switch off the sharpen layer but no changes are visible in this magnification. So I zoom into the image .

|And I think you should see the effect properly. When I on the sharpen layer you see the sharpened image and when I off it the image is not sharpened.

|With the help of the opacity slider I can control the amount of the effect. Now  I check the background and you can see I have not harmed it.

|09:54

|Now i’ll do some fine tuning.

|And I look in to the image for over sharpened areas and the stuff which is not good enough sharpened. The border between the flower and background is very well sharpened & with no add effects. But when I go into the flower, this part looks a bit artificial and this part here is definitely over sharpened.

|And this flower bud here is not sharp enough because the edge detect algorithm found no edges. But as you can see there are some edges and I should have given this part a bit more boost with the help of the levels tool or with the curves tool.

|Sharpening should always be last step in your work flow.

|Ok I’ll come back to that later. Now I have to reduce the sharpness of this part. It’s easy, just make sure that you have selected the sharpen layer, choose the brush tool.

|Choose a brush with soft edges, and make the brush large enough for this job by pulling the scale slider and now select the black colour, because you remember black hides & white reveals. And pull the opacity slider of your brush to say 20%.

|When I move the brush here and start painting, you can see that the sharpening is reduced. I can show you exactly what happens here with the help of layer mask. I on the layer mask and when I paint over the white part, it turns darker.

|But when I turn off the layer mask I can see the image and can see the result of my operation.

|I’ll look into the details later.

|Now I have to do more sharpening to this part here. I just switch the colours with ‘x’ key and start painting. And as you can see this part gets sharper and darker. And I think this is quite good and to check my work I switch on the layer mask and you can see this white part is what I have painted and I have done it a bit over. So I go back to the layer and change the colour by pressing X key and redo the work I have done.

|We are working with the layers here so there is no danger of losing any data. The only thing that I can destroy now is the edge data that has been constructed by the filter. But that can easily be redone .

|Here I have zoomed into the edge of the flower where the sharpening has been done. And as you can see the edge is sharpened here. The sharpening helps in getting a bright and dark line between the dark and the bright part of the border between these 2 colours. The edge of dark part is darkened and bright part is brightened. And by using the mask you can keep the effect only to the area you want to have it.

|Go to tips from the top floor.(dot)com the site of Chris Markwa’s broadcast and there on the left side you will find somewhere a Photoshop corner.

|And there he has lot of broadcast about Photoshop which nearly are usable for GIMP too and he has made the effort as writing stuff he says in the broadcast and made some picture of it and I’ll take some material from there, so I can point a directly to the source here.

|And here you can see about the sharpening effect about which I discussed in this tutorial. He also covers the Unsharp mask and the process to avoid the halos in detail. And shows lot of different techniques to sharpen the image. But the one I showed you is not here on this site.

|And By the way when you are on this site just check out if there are still some places on learning to see workshop.

|This was it for this week. If you want to send a comment, please write to info@meetthegimp.org

| More information is available at http://meetthegimp.org . And I would like to hear from you.  Tell me what you liked, what I could have made better, what you want to see in the future.  

| This is Hemant Waidande dubbing for the Spoken Tutorial Project.