Selective sharpening
I've been asked about selective sharpening using Photoshop, so here is how I go about it. I should say first of all that I use Photoshop Elements 2.0, which is rather dated. Some of the commands I mention may be located differently in other versions of Photoshop, or there may be quicker ways to do some things. Why sharpen selectively? Standards on a.net and jp.net, particularly a.net, are very stringent nowadays. They like photos sharp, but they abhor the jagged edges that too much sharpening can produce. The problem is that you might get jagged edges in one part of an aircraft, such as a wing leading edge, while the rest of the aircraft remains too soft. Selective sharpening solves this problem. Preliminary steps The first part of my workflow involves rotating the photo to level it, cropping (without resizing at this point), removing dust spots with the help of the Equalise feature and adjusting levels. I then save the result as a TIFF file. I keep this TIFF file just in case I need to produce a high-resolution version for publication purposes of any photo I upload to a.net or jp.net. (I'm still waiting for the world press to beat a path to my door asking me to name any price for the use of my photos. Any day now ... :wink: ) If all has gone well, all I have left to do is resize and sharpen. I resize in stages because I have found that Photoshop (or at least my version) can produce jagged edges on diagonal lines if I resize a large file down to 1024 pixels wide all in one go. I save the resized file as another TIFF. First pass Next comes the sharpening proper. The first thing I do is to create a new layer by selecting "new" then "layer via copy" from the Layer menu. This creates two identical copies of the same photo one above the other. I then apply one pass of unsharp mask (USM) set at amount 500, radius 0.2, threshold 0. Having done this, I scrutinise the photo carefully to look for jagged edges, or jaggies. Typically they are found on fuselage titles and cheat lines, wing and stabiliser leading and trailing edges, and other diagonal lines. In photos taken from ahead and below, the gap between the flaps and wing undersides is usually very prone to going jagged. I remove these jaggies with the eraser tool, that is to say I rub away the top layer to expose the original unsharpened layer of the photo. Where the jagged edges are only just starting to appear I apply the eraser tool at 50% opacity, meaning it blends the two layers rather than removing the top one altogether. Next I merge the two layers by selecting "flatten image" from the Layer menu. Second pass One pass of USM is usually not enough so I repeat the process but with USM settings of 250, 0.2, 0. (The 250 setting is typical but varies according to need.) Once again I check for jaggies, apply the eraser tool as necessary, and merge layers. Third pass As a final stage, I select the sharpen tool from the palette (same place as the eraser tool), select a size of 10-15 pixels and a strength setting of say 10%, and go over any areas of detail that strike me as still looking soft - typically cabin windows and wheel hubs. The low strength setting makes sure I don't ruin all by overdoing it at this stage. At this point the photo is ready so I save the changes and then make a JPEG version for uploading. In case you're wondering why I don't stick to JPEG format throughout, it is because every time you save a JPEG you compress the photo, which degrades quality. TIFF enables you to save as often as you like. If the photo gets rejected, I go back to the TIFF to try to fix the problem. This is how I go about selective sharpening. Other people use different approaches that work for them equally well. For instance, some like to apply multiple passes of USM at 50, 0.3, 0. I think the 0.3 setting can contribute to prominent halos (white outlines around high-contrast edges), but don't ask me for solid proof. How much sharpening is enough? Keep in mind that the amount of sharpening you need will vary depending on your camera, your lens and (if your lens is a consumer-grade product like my Canon 75-300) the focal length and aperture at which you shoot the photo. The hardest thing I have found is not learning to use Photoshop but developing an eye for how much sharpening is needed. In the old days the advice was "sharpen until jaggies start to appear", but this is not much help. As I mentioned earlier, the appearance of jaggies in one place does not mean that the photo as a whole is sharp enough! The fact that monitors vary in sharpness does not help either: I use three regularly and I am still surprised at how much difference there is between them. It helps to look for similar photos to yours on a.net or jp.net and compare them. And it is important to scrutinise the whole photo in detail when you are sharpening. Now try this ... Want to test your eye for sharpness? Look at these photos. 1.http://www.jetphotos.net/viewphoto.php?id=369443
I uploaded this photo to jp.net almost two years ago at a time when standards were not as high as they are now. Today it would almost certainly get rejected. Why?
2. http://www.jetphotos.net/viewphoto.php?id=547137
This photo was accepted by jp.net but rejected by a.net, and today it would probably be rejected by both. Again, why?
Answers:
1. Jaggies. Look at the wing and tailplane leading edges, and the nose underside in particular. This photo is a classic example of why selective sharpening is needed, but if you mentioned it to me at the time I'd have looked at you blankly and said "Huh?"
2. Did you find any jaggies here? The Star Alliance titles are a little oversharp, but the real problem with this photo is the opposite - softness. Look at the nose area. I have no idea why this sort of localised softness/blurriness happens: I do not think that it is a depth of field problem. But it happens. This photo is an extreme case, but it illustrates the need to scrutinise all areas of a photo before you pronounce it ready for uploading.
I've been asked about selective sharpening using Photoshop, so here is how I go about it. I should say first of all that I use Photoshop Elements 2.0, which is rather dated. Some of the commands I mention may be located differently in other versions of Photoshop, or there may be quicker ways to do some things. Why sharpen selectively? Standards on a.net and jp.net, particularly a.net, are very stringent nowadays. They like photos sharp, but they abhor the jagged edges that too much sharpening can produce. The problem is that you might get jagged edges in one part of an aircraft, such as a wing leading edge, while the rest of the aircraft remains too soft. Selective sharpening solves this problem. Preliminary steps The first part of my workflow involves rotating the photo to level it, cropping (without resizing at this point), removing dust spots with the help of the Equalise feature and adjusting levels. I then save the result as a TIFF file. I keep this TIFF file just in case I need to produce a high-resolution version for publication purposes of any photo I upload to a.net or jp.net. (I'm still waiting for the world press to beat a path to my door asking me to name any price for the use of my photos. Any day now ... :wink: ) If all has gone well, all I have left to do is resize and sharpen. I resize in stages because I have found that Photoshop (or at least my version) can produce jagged edges on diagonal lines if I resize a large file down to 1024 pixels wide all in one go. I save the resized file as another TIFF. First pass Next comes the sharpening proper. The first thing I do is to create a new layer by selecting "new" then "layer via copy" from the Layer menu. This creates two identical copies of the same photo one above the other. I then apply one pass of unsharp mask (USM) set at amount 500, radius 0.2, threshold 0. Having done this, I scrutinise the photo carefully to look for jagged edges, or jaggies. Typically they are found on fuselage titles and cheat lines, wing and stabiliser leading and trailing edges, and other diagonal lines. In photos taken from ahead and below, the gap between the flaps and wing undersides is usually very prone to going jagged. I remove these jaggies with the eraser tool, that is to say I rub away the top layer to expose the original unsharpened layer of the photo. Where the jagged edges are only just starting to appear I apply the eraser tool at 50% opacity, meaning it blends the two layers rather than removing the top one altogether. Next I merge the two layers by selecting "flatten image" from the Layer menu. Second pass One pass of USM is usually not enough so I repeat the process but with USM settings of 250, 0.2, 0. (The 250 setting is typical but varies according to need.) Once again I check for jaggies, apply the eraser tool as necessary, and merge layers. Third pass As a final stage, I select the sharpen tool from the palette (same place as the eraser tool), select a size of 10-15 pixels and a strength setting of say 10%, and go over any areas of detail that strike me as still looking soft - typically cabin windows and wheel hubs. The low strength setting makes sure I don't ruin all by overdoing it at this stage. At this point the photo is ready so I save the changes and then make a JPEG version for uploading. In case you're wondering why I don't stick to JPEG format throughout, it is because every time you save a JPEG you compress the photo, which degrades quality. TIFF enables you to save as often as you like. If the photo gets rejected, I go back to the TIFF to try to fix the problem. This is how I go about selective sharpening. Other people use different approaches that work for them equally well. For instance, some like to apply multiple passes of USM at 50, 0.3, 0. I think the 0.3 setting can contribute to prominent halos (white outlines around high-contrast edges), but don't ask me for solid proof. How much sharpening is enough? Keep in mind that the amount of sharpening you need will vary depending on your camera, your lens and (if your lens is a consumer-grade product like my Canon 75-300) the focal length and aperture at which you shoot the photo. The hardest thing I have found is not learning to use Photoshop but developing an eye for how much sharpening is needed. In the old days the advice was "sharpen until jaggies start to appear", but this is not much help. As I mentioned earlier, the appearance of jaggies in one place does not mean that the photo as a whole is sharp enough! The fact that monitors vary in sharpness does not help either: I use three regularly and I am still surprised at how much difference there is between them. It helps to look for similar photos to yours on a.net or jp.net and compare them. And it is important to scrutinise the whole photo in detail when you are sharpening. Now try this ... Want to test your eye for sharpness? Look at these photos. 1.