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I'm trying to downsize a very large app logo with alpha transparency in Photoshop CC, but I can't seem to replicate the sharpness that I get using paint.net.

Below are a couple images I've created to illustrate the problem. I started with a 5000 px circle and resized it down to ~90 px using various resampling algorithms.


paint.net - "Best Quality" / Fant
This seems to produce the best result
fant


Photoshop - Bicubic Sharper
Notice the thickened, blurred outer edges along the sides, top, and bottom of the circle
bicubic-sharper


Photoshop's bicubic smoother, bicubic smooth gradient, and preserve details resampling algorithms all seem to exhibit the same problem as bicubic sharper. The bilinear algorithm has a similar edge-thickening problem, but the edges look a little more jagged. Nearest neighbor is the only resampling algorithm in Photoshop that doesn't seem to thicken the horizontal and vertical edges of the circle, but it results in extremely jagged edges.

Am I doing something wrong? Is there anyway to match paint.net's Fant algorithm in Photoshop CC?

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Not sure why you'd choose to work this way... but my answer is:

  1. Ctrl + click on the layer thumbnail of your large image.
  2. Go to Window > Paths and at the bottom choose Make work path from selection
  3. Go back into the Layers Panel and with your layer active Ctrl + click on the Add layer mask button
  4. Now scale your image, and export

Here is the resulting image:

enter image description here

  • @macro This method keeps the transparent area clean by adding a vector mask that scales down pefectly. If there were more colors than one, this wouldn't improve the downscaling of the color borders. Generally this is useful, but for single color cases this is perfect +1 – user287001 May 28 '17 at 7:42
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I have found Photoshop's Bicubic Sharper algorithm useful most of the time, but sometimes, as in your example, it's less than ideal. Even GIMP with it's Sinc(Lanczos3) algorithm makes a better job of reduction with your example image.

However there is a workaround that might help you. Since you have an alpha channel to work with already, if you CTRL(Command on Mac)+click the image layer thumbnail, to make a selection, and then press CTRL(Command)+T, and rescale it by entering the number of pixels in the tool bar along the top, the result is much better. I rescaled the circle to 100 pixels square using that method in the example below, then I cropped it with no resampling.

Example of Scaling

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    I like lanczos filtering, and i dont like Adobes signal processing prowess. In either case you can use smart sharpen to adjust the look. But Lanczos is quite close to as good filtering as you can theoretically get unless you know something more about the physical processes involved or have a mental preference. – joojaa May 27 '17 at 9:09
  • @joojaa - Yes, I do wish Adobe would include a lanzcos algorithm - perhaps they should pay attention to the what the free competition is doing. Yes smart sharpening might solve it too, but really Adobe needs to try a bit harder. – Billy Kerr May 27 '17 at 9:14
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    To be honest not pay attention to what free ones are doing but what scientists are saying you should be using. – joojaa May 27 '17 at 9:17

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