Wednesday, July 13, 2011

Improved Method of High Pass Filter Sharpening

It's those little problem areas that upon closer inspection, especially if image is to be printed large, are occurring throughout the image in less intensity. But they are still there.

I have many times used the blur tool in sharpening layers to reduce some of the inherent noise that the process of sharpening brings by its very nature of operation.

I normally don't use the High-pass method in many larger prints I make because of this increased noise, especially in soft areas like clouds or flower petals.

The leaf cluster on bottom left was added from another version to give this photograph a standard triangular view with focal points

To alleviate these noise problems I decided to first blur the high pass filter layer  and then apply a curves adjustment layer to the high pass layer only, to improve contrast with some of the softness created by blurring.

Detailed PDF Document Available
I experimented with 5 other combinations including using the luminance filter (noise reduction) in ACR
for input to High Pass Filter Sharpening.  This document contains numerous photos clearly detailing the process and results from 6 versions. One being the camera default.

It is available on Niels Henriksen Artworks site at the following link.

The reason for creating it in a book format is it allows me greater control over layout and by shifting to a landscape format should filter better with our horizontal monitors.

Let me know what you think about the PDF version.

The above photo shows results for using the high pass filter only and then repeating with a curves adjustment layer applied.  You can see how the veins are crisper and if you look carefully there is less noise on the smooth stamens. The PDF article shows a close up of stamens.

A setting of 2.1 was used for both Gaussian blur and high pass filter. It's always going to be a trade-off between reducing noise when sharpening and still having good edges.

This process will make it easy to create an action in Photoshop, whether modifiable or a straight run.

This is original version. I cropped the details on the  right and also removed some of the leaf tips near flower cluster.  Leaves from another image at wider angle wear to balance the composition.

I always try and take a few extra photos at a wider angle for that just in case you need it.

Niels Henriksen


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