7 Sharpening Artifacts To Avoid


If you know what to look for, you’ll know what path to choose and how far down it to go.
Identifying and developing a sensitivity for the artifacts digital sharpening produces will help you choose a sharpening method and what settings to use during any stage of your sharpening workflow.
You can easily see the artifacts digital sharpening produces by overdoing it.
Here are the seven most common digital sharpening artifacts.
1         Noise
2         Exaggerated Texture
3         Visible Light Halos
4         Visible Dark Lines
5         Loss of Highlight Detail
6         Loss of Shadow Detail
7         Increased Saturation
Each of these artifacts can be reduced in one or more ways.
Here’s a list of options.


Insights Members can login to read the full article.
Email:
or Sign up

Creative Sharpening – Control Halo & Line Separately


Digital sharpening produces its affects by accentuating contrast, both of texture and of contour. The accentuation of contrast along contours is produced by creating both a dark line and a light halo. While the filters used to sharpen images, such as Unsharp Mask or High Pass, don’t offer independent control of the light and dark components of a contour, you can control them separately using layers. It will take two layers to separate halo from line; one for the halo and one for the line. Filter the two layers differently to produce different thicknesses (Radius) and intensities (Amount) of halos/lines. Then, you can use the Blend If sliders of layers to specifically target either high or low values by moving either the shadows (black triangle) or highlights (white triangle) sliders of This Layer, making those values no longer visible. Some people like to set the Opacity of these two layers to 50% before filtration, so that they can conveniently readjust the intensity of the affect, moving the opacity slider up to make it stronger or down to make it weaker. If you do this too, remember that only the filter’s Radius setting can adjust the thickness of the contours it produces.


Insights Members can login to read the full article.
Email:
or Sign up

Target Image Contours With Edge Masks



Edge masks target only the contours in an image. (Think of edge masks in Photoshop as the creative sharpening equivalent to the Masking slider in ACR or Lightroom’s capture sharpening.) They keep smooth areas smooth, while accentuating the contrast/sharpness of contours. They can be particularly useful for images that contain moderate to significant amounts of noise. In many cases, they allow the use of more aggressive applications of sharpening effects. Edge masks can help you take all of the creative sharpening effects you design up a notch – or two.


Insights Members can login to read the full article.
Email:
or Sign up

High Pass Sharpening

No High Pass sharpening

Low Radius High Pass sharpening

High Radius High Pass sharpening

There are three methods of sharpening in Photoshop that we should all be aware of: Luminance, Edge and High Pass sharpening. In this order, the three methods become progressively more complex and go to greater lengths to reduce the accentuation of noise.


Insights Members can login to read the full article.
Email:
or Sign up

Unsharp Mask



Precise sharpening can improve almost any image. It helps to know when to apply it, what type of sharpening to apply, how to apply it and where to apply it. Forget the filters Sharpen, Sharpen More and Sharpen Edges. They're just default settings of Unsharp Mask. Even Smart Sharpen offers few advantages over Unsharp Mask; it's particularly useful for compensating for trace, but not substantial, amounts of motion blur. My advice? Start with the classic and master it.
Why is a filter that makes images appear sharper called Unsharp Mask? In silver-halide-based photography, unsharp masks are made with out-of-focus negatives that are registered with an original positive image. During exposure, the blurring adds contrast around contours, making images appear sharper. Digital unsharp mask works the same way; it uses blurring algorithms to add contrast to contours, again making images appear sharper.


Insights Members can login to read the full article.
Email:
or Sign up

Detail Frequency

High frequency detail

Medium frequency detail

Low frequency detail

Frequency is a term that’s being used more and more. That’s because new tools offer you more control over frequency than ever before. Noise reduction, sharpening, and HDR all offer unprecedented control over the look and feel of detail in our images. Frequency is used to describe the amount of detail packed into a given area of an image. This is measured by the amount of tonal variation between rows or columns of pixels. Imagine measuring an image with a line that passes across it (horizontally from left to right or vertically from top to bottom). The mean or average tonal value along lines can be charted and then compared to values from other measurement lines, especially those nearest to each other.


Insights Members can login to read the full article.
Email:
or Sign up

Capture Sharpening


Optimal image sharpening is best done in three stages— capture (do it during RAW conversion), creative (do it in Photoshop) and output (automate it).
Capture sharpening benefits all images. It compensates for inherent deficiencies in optical and capture systems. All lenses and sensors have specific characteristics and deficiencies. They don't all have the same characteristics or deficiencies.
To speed your workflow, default settings for a best starting point for capture sharpening can be determined for all images created with the same lens/chip combination and saved for subsequent use. To optimally sharpen an image, you'll need to modify these settings to factor in additional considerations—variances in noise (ISO, exposure duration, temperature), noise-reduction settings and the frequencies of detail (low/smooth to high/fine texture) in an image.


Insights Members can login to read the full article.
Email:
or Sign up

Sharpening Workflow


The vast majority of photographic images benefit from sharpening. Before you decide how and when to sharpen images, you need to decide why you’re sharpening them. The goal is to enhance detail rendition without producing distracting visual artifacts. You’ll find many conflicting philosophies and their accompanying strategies for sharpening images. The seemingly conflicting advice can be hard to reconcile.
Should you sharpen once or multiple times? Should you sharpen differently for different subjects? Should you sharpen differently for different sizes? Should you sharpen differently for different presentation materials or supplies? Should you view your files at 100% or 50% screen magnification?


Insights Members can login to read the full article.
Email:
or Sign up