![]() ![]() Go back to the hands image, and open its Channels window. Click on the Cross to get rid of the preview. There are several things wrong with this, which we'll now correct.You should get something looking like this (scaled for the web):.The image will only be rendered when you fix it, either by pressing Space or clicking on the Tick. It's important to realise that this is only a preview nothing has been drawn so far. If the hands aren't placed right, just drag them around. An outline will follow the mouse, and when you release the Select button the image will appear (providing the Copy: Preview icon is on). Now just drag the hands (click and hold anywhere inside them) onto the sunset picture.Open the Copy window menu, and load your saved selection ( Copy >Load from>#4 Alpha).Make sure the hands image is currently active (click menu anywhere over the image), and ensure you're in Montage mode. Load this into Photodesk, alongside the hands.Sunset over Chapel Allerton with Moon and plane This process is sometimes known as "defringeing" or "dematting" you can get a similar effect while you're actually making a selection by using the Feather option in the Copy window. This blurs the edges slightly and gives a much better effect when you paste it somewhere it ensures that edge pixels will 'blend' in colour with the destination. To fix this, click on the Grow icon this adds a small amount to the edges of the mask. When we come to paste it somewhere this will show up, especially if it's a contrasting colour. Notice how there's an unpleasant blue outline round the hands, caused by imperfect selection.Click on the Palette icon to go back to painting mode, then click on the Mask icon on the toolbar the Masking effect window will open. Now that we have a mask, we can do some useful and interesting things.The overall sharpening varies very little if the blurring is out by +/- a pixel or so.Feedback : hosted by : the iconbar now : The radius should be set to the approximate width of this edge. The blur radius can be assessed by magnifying the image and examining a supposed sharp edge. Values between 150 - 190 seem to be about right depending on how sharp the original is. The higher the equalise factor the greater the sharpening although as it gets "too sharp" it tends towards high contrast edges. The relation between the equalise adjustment and the gain factor in the calculate step should be : Malcolm Ripley did some experimenting after reading this page, and has some useful advice: One sign that you've 'overdone it' is the presence of dark halos around bright objects (particularly noticeable in images of stars, for instance).You will need to try various values out to get the best effect. The various settings are very dependent on the nature of the original image.This method of image sharpening originates with 'real' film, as a darkroom technique.Drag the bottom of the right-hand dotted line to the left, until the bottom right number in the "Map" section is about 170:.Select Equalise, open the details pane, and ensure that the type is linear and the channel is RGB.Ensure the moonblur image has the input focus, and open the Image processing window. ![]() As usual, do the brightness and contrast adjustment first. We want to make a reduced-contrast, dimmer and very blurred version of this image.Open the main image menu, go to File>Copy, type moonblur in the writeable icon and press return. Start by getting the original image into Photodesk, and save it as moon in Photoshop format.It seems counter-intuitive, but the results can be astonishing. You take a copy of a blurred image, make it much worse, then subtract it from the original. The technique can appear almost magical at first. This offers more control and much better quality, but does require extra work and is harder to get right. #Icon photodesk how toHere we'll look in more detail at unsharp masking, and show how to do it 'by hand'. The section on basic image sharpening showed how to use Photodesk's built-in unsharp mask facility to enhance a picture of the Moon. Go : home | tutorials | real unsharp masking ![]()
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