Double USM | Advanced Control of Dark and Light Halos
Double USM is a sharpening tool working separately on Dark and Light halo’s components of an image, an impossible task until today. With a double set of sliders and his high-quality preview, Double USM fills the gap and lets you tweak halos precisely, to fit your image processing need. For traditional, hiraloam (high radius and low amount) or creative mixed sharpening.
The Basics of Unsharp Mask
Despite its name, Unsharp Mask is used to increase the perception of sharpness in an image and to get a sharper print in offset or fine art prints. However, the “un-sharp” term to name an action that makes an image more-sharp, has a reason why. In this technique, the increasing of sharpness is obtained blurring a positive copy of the image and combining it with a negative copy of the basic picture. The resulting final version is sharper, or less blurry if you prefer than the original. USM, if correctly applied, improves texture and detail. So, through the blurring of an image, you get a sharper image.
- Works separately on dark and light halos 70%
- Exclusive Mixed Sharpening (a combination of Traditional and Hiraloam) 85%
- High quality preview 50%
Light and Dark Halos
The above mentioned mask exaggerates the light-dark contrast between the two sides of an edge creating light and dark halos in the boundaries of the edges. If you can control the amount and features of this halos, the result is excellent, if not it may be ugly or even unacceptable.
The apparent detail that USM is creating out of nowhere is made with halos along borders where areas of different luminosity meet. Light Halos are created on the light area’s border. The Black Halos on the black area borders. (see the image on the right). Traditional Unsharp Mask filter doesn’t allow you to control the values of Amount and Radius separately which is exactly what Double USM is here for.
Traditional Sharpening (High Amount, Low Radius). Double USM does it better
This is what we’re mostly used to high frequency detail boosting (i.e. small features and borders). Standard sharpening values include high Amounts (up to 500% if you’re heavy-handed) and small Radii (it depends on the image size and the output – display, print/press – but we talk about values ranging from 0.3px for the web, up 2.0px or more). The threshold is really up to you and must be evaluated on each picture.
Default Values Preset “Default”: D (300, 1.5), L (150, 0.7), T (0) as example below. Optimized for offset print.
Reduce layer’s opacity to 70% for digital printers, or at 50% for the internet and monitor display.
HiRaLoAm Sharpening (Preset: HiRaLoAm Darker/Lighter)
HiRaLoAm sharpening add a 3D look at your images enhancing the shape of the subjects. “HiRaLoAm” stands for High Radius, Low Amount. Bigger radii (unusually broad) at low Amounts (lower than 100%) sculpt the subject and add shape.
Default Values Preset “Hirhaloam Darker” : D (50, 50), L (30, 30), T (2) “Lighter”: D (30, 30), L (50, 50), T (2)
as an example below – The difference when printed is much more evident.
Mixed Sharpening (a combination of Traditional and Hiraloam). Preset: Creative
HiRaLoAm sharpening adds a 3D look at your images enhancing the shape of the subjects. “HiRaLoAm” stands for High Radius, Low Amount. Bigger radii (unusually broad) at low Amounts (lower than 100%) sculpt the subject and add shape.
D (300, 1), L (50, 20), T (2) – Optimized for offset print. Reduce Double USM layer’s opacity at 70% for digital printers, or at 50% for the internet and monitor display