Scanning experiences: Moirée patterns and white point

Discussion in 'Tips, Tutorials & Tools' started by Leif Oh, May 4, 2005.

  1. k5083

    k5083 Member

    Apr 13, 2005
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    Maybe Gerardo has answered your question, since his procedure is similar to mine. I use Noiseware mainly for removing moire effects created by interference between the scanning matrix and the printed halftone patterns that were scanned. I generally scan at 300dpi and use Noiseware for the first stage of my post processing, before I do any tonal or color correction, set white points, or any of the other things we've talked about in this thread. Noiseware prefers unprocessed images. Although its moire removal abilities are not highly touted on its web site, they are very good. The older and more crudely printed the model, the better it works. Old Maly kits are a great example, like Gerardo says.

    Attached is before-and-after comparison of a corner of the flight deck of the JSC 1/400 USS Intrepid, which I scanned at 300dpi. The left half of the pic is right off the scanner; the right half has Noiseware applied with the default settings, otherwise it is untouched. I've been very impressed with the way Noiseware holds the detail in the lines and edges while removing the moire texture effect. If you copy this image and blow it up 2x or 4x, you'll see even better what I mean. Noiseware has several options and settings for how completely you remove the noise -- the default, as shown, does not smooth it completely, that actually looks a little weird -- and can also combine the noise reduction with sharpening or color enhancement, which I generally avoid.

    Maybe if you played with the radius of the Median filter in Photoshop in combination with masks or layers to control the degree of smoothing, you could achieve the same results. But I spent a fair number of hours trying to learn that tool and never got as good results as Noiseware at the default settings. I think the advantage of Noiseware is its ability to analyze the image and figure out the frequency of the dominant noise in the image. With the Photoshop Median tool, you can go crazy trying to figure out what radius to set, given that it's invariably a fractional number of pixels.

    Anyway, once my scan is smoothed out, I do all the other good stuff in this thread.