Final processing steps include removal of any remaining hot and cold pixels, correction of excessive halos around bloated stars, and cropping the images. Zoom into your image at 200% or 300% to identify bad pixels. Many of these can be erased quickly using the spot healing brush tool in Photoshop. If you are using another software program or an earlier version of Photoshop, try the clone stamp tool to sample an adjacent area of normal signal and then paste over the artifact. Adjust the tool to the size of your artifacts, and keep hardness low to create a smooth transition. For repair of residual blooming spikes, try the clone stamp with an opacity of under 100% to gradually conceal the spike.
Bloated stars and halos can be corrected in many ways. If you have just a few bloated stars, begin with the lasso tool to select a generous area around the worst offending star and halo. Select additional stars by holding the shift key while employing the lasso tool. Feather your selection by a few pixels. Then use the minimum filter (filter, other, minimum) at a setting of 1 or 2, which will shrink both the halo and star. If the effect appears too harsh, you can fade the effect (edit, fade minimum filter) to less than 100%. If you have many halos to correct, you can select most of the halos at once using the color range command (select, color range) with the eyedropper tool. Expand your selection by a few pixels, and then feather your selection. Apply the minimum filter at a setting of 1, and then fade the filter if necessary. If the halos have an odd green tone, you can reduce their saturation (image, adjustments, and hue/saturation).
Image alignment leaves dark borders around many images, which creates a noisy edge to your final image. Initial cropping should eliminate this border. You may perform additional cropping to create a more balanced image. Avoid cropping to just place your target in the center of the image. Many images will appear more dynamic with the main target off center, especially if the target is balanced by some bright stars, nebulosity, or background galaxies in the other side of the image.
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Adobe Photoshop can be a complex tool only because you can do so much with it, however for in this video series, we're going to keep it as simple as possible. In fact, in this video you'll see an overview of the few tools and Adobe Photoshop features we will use. When you see this video, you'll see how you can do so much with so few features, but you'll learn how to use them in depth in the future videos.