by Chris Peterson » Thu Sep 20, 2012 1:44 pm
owlice wrote:I often have to reduce the resolution and size of images. There are different algorithms for scaling images; star trail images usually reduce well with one called "Smooth." But this time, I'm not so sure. Which of these scaled images is better? By "better," I mean which, of the two, do you like the best, would you choose to post on the submissions thread to best show off the photographer's work?
I think the left image is significantly better, both in reduced and full views.
I find that the best reduction strategy is simple: always use basic bicubic resampling- no sharpening or smoothing in the reduction algorithm at all, then apply either an unsharp mask or Gaussian blur afterward, depending on your results (blurring is sometimes necessary when you have star trails, to minimize aliasing). This approach is easy, and gives the most control.
[quote="owlice"]I often have to reduce the resolution and size of images. There are different algorithms for scaling images; star trail images usually reduce well with one called "Smooth." But this time, I'm not so sure. Which of these scaled images is better? By "better," I mean which, of the two, do you like the best, would you choose to post on the submissions thread to best show off the photographer's work?[/quote]
I think the left image is significantly better, both in reduced and full views.
I find that the best reduction strategy is simple: always use basic bicubic resampling- no sharpening or smoothing in the reduction algorithm at all, then apply either an unsharp mask or Gaussian blur afterward, depending on your results (blurring is sometimes necessary when you have star trails, to minimize aliasing). This approach is easy, and gives the most control.