Hiroloam / unsharp mask

asamuel

Quick one. I cannot tell from what I've read if Hiroloam is recommended to be used additionally to unsharp mask. Or is it an alternative?

Richard

asamuel wrote:

Quick one. I cannot tell from what I've read if Hiroloam is recommended to be used additionally to unsharp mask. Or is it an alternative?

Hiraloam is useful for increasing the overall contrast and accenting contours. It is actually just a special set of parameters you use in unsharp mask (high radius, low amount). The more common use of USM is to sharpen edges. Which one you use is entirely a matter of what you think the image requires, and you can use both if you like. When using both, I find I get better results if I do the hiraloam first, then the normal USM.

FWIW,

asamuel

thanks rsinmadrid, you often come to my rescue! Thats cleared things up plenty

DavidTO

I think that HIROLOAM actually increases LOCALIZED contrast, not overall.

BinaryFx

DavidTO wrote:

I think that HIROLOAM actually increases LOCALIZED contrast, not overall.

I would tend to agree David - but I guess it depends how high the radius is!

When Dan Margulis uses this method, it often does not have a huge radius - but it is a lot larger (and lesser in amount) than the regular sharpening halo width that is commonly applied by most folk (be it acquisition sharpening, subjective creative sharpening or output sharpening).

As this thread is about HIRALOAM, I agree that local contrast is the important aspect here, as that is Dan's aim.

Moving off topic for HIRALOAM, but still related - many use a technique of a extremely high radius and low amount setting in USM which goes past localized contrast and affects overall contrast (or they may use high pass and blending modes and opacity instead, but the goal is the same). This may be referred to by some as 'midtone contrast'.

This is often needed when people overly rely on histogram and fear of clipping their images. So the extreme endpoints are protected so as not to clip extreme values (even if the areas are not critical to a human observer) and then the midtone contrast is enhanced to make up for the lack of contrast from the use of more conservative white/black point and overall contrast settings. As Dan often targets important areas of the image to enhance range (the steeper the curve concept) - midtone contrast enhancements are a natural effect of setting the endpoints and contrast (at the expense of blowing out the extreme ranges in non critical ares of the image).

More on USM and HIRALOAM can be found in one of two free sample chapters from Dan's latest book:

http://www.ledet.com/margulis/articles.html
http://www.ledet.com/margulis/PP5E_Ch06_r1.pdf


Best,

Stephen Marsh
http://members.ozemail.com.au/~binaryfx/