Control Your Sharpening Halos

I wrote a tutorial explaining how to separate and control the light and dark halos created by Photoshops Unsharp Mask filter. Here is a link to my sharpening tutorial.

Let me know if it makes sense to you.

It makes sense but if you're sharpening to the point where you get halos then you need to focus better in the first place.

excellent tutorial: I do post processing for products: this will help immensely!
Thank You.

Really...what's your keeper rate Hanko my boy?

chauncey wrote in post #8463760
Really...what's your keeper rate Hanko my boy?

Except for the occasional session of motorsports which I'm rubbish at, I'd say around 70%. Why? What's that got to do with focus?

It's a well-written tutorial.

Using Darker Color and Lighter Color will avoid color shifts that tend to come with Lighten and Darken.

However, this technique alone will not avoid visible sharpening halos.

What the technique allows is for you to sharpen separately the light and the dark sharpening contours. Typically, halso become obvious along the lighter contour sooner. So, you can get more aggressive about the sharpening settings with the darker contour.

You are correct that a grayscale example is not all that helpful here.

This technique will also get you some sharper halos then you might expect. The problem with Lighten color and Darken Color is that they do not create any new blended color. Instead, they just select what is lighter/darker from the two layers. A blended color might be less of a change.

If you want to separately affect the light and the dark contour, I suggest you not use a form of darken/lighten blend modes. Use Blend If sliders. That way, you can use a Luminosity blend to avoid color shifts and you can have more gradual transitions along the sharpening contours.

That's the approach I use in my eBook/video on sharpening. I explain why Blend If is superior to using color blends.

http://www.thelightsri​ght.com/SharpeningYour​PhotographsED

Blend Ifs is also the approach recommended by Fraser and Schewe in their book on sharpening and theit tool. PhotoKit Sharpener.

Cheers,

Mitch

Thanks for the input Mitch. I used the blend if sliders for a long time, but I found this method of splitting the light and dark halos is quicker and more manageable for me. My computer is old and the blend if sliders cause a considerable amount of processing time. I could still see some use for the blend if sliders when sharpening, but I didn't want to cover every single sharpening scenario in one tutorial.

I totally agree with you about using the darker/lighter blending option rather than darker color/lighter color. However, I do almost all my sharpening in the LAB colorspace and darker/lighter is not available in LAB. I think lighter color/darker color works well in LAB because that blending option treats each channel as a color when it looks for lighter or darker areas. That means the the Lightness channel is considered a color (sort of)when Photoshop looks for a darker or lighter color. Furthermore, if you do your sharpening on the lightness channel only you should be able to avoid all color shifts. I think I should have put those points in the tutorial, but I left them out because I thought it was going a little too deep for most readers. Maybe a rewrite is in order.

I know the L*a*b maneuver is popular. It shouldn't be.

There is no practical advantage to L*a*b Lightness channel sharpening compared to staying in RGB and using a Luminosity blend.

Yes, you can blow the two up to 1000% and in rare cases ylou can see very minor differences. At print size, even with big enlargements, I have yet to see an example where one would be satisfied with L*a*b and unsatisfied with RGB and Luminosity blend.

The problem with L*a*b is going through the color engine twice. It's a there and back thing. So, unless all yoiur photos have really weird clolor casts from multiple light sources or need huge saturation adjustments, you should avoid going to L*a*b. Going to L*a*b just to sharpen is not a good idea.

If you doubt this, I'd like to know of a single commercial sharpening tool that performs its work on the L*a*b Lightness channel.

Now, if I was in L*a*b to fix a serious problem, I'd go ahead and sharpen the L*a*b channel.

Your choice of Lighter Color and Darker Color is even more likely to cause harsh transitions in L*a*b. You cannot get a wider color space. A wider color space means that change from one level to the next is a larger shift in color. IOW, posterization is more likely for any adjustment. Especially non-linear adjustmens, like sharpening, which push some pixels around more than others.

Cheers,

Mitch

Anyone ever try High Pass (blended to soft light or overlay) for sharpening? I find it to be more realistic than unsharp mask.

gregpphoto wrote in post #8474309
I find it to be more realistic than unsharp mask.

High Pass on it's own is often better than poor USM, but USM done well - with blend-if layers, masking, brushing, etc - can't be beat.

i use Highpass on Hard Light works great, and i can mask it if needed as well

Scottes wrote in post #8474337
High Pass on it's own is often better than poor USM, but USM done well - with blend-if layers, masking, brushing, etc - can't be beat.

If you shot it well, you won't need but a pinch of sharpening anyway. In fact, I use High Pass on a shade above it's lowest setting, masked as well.

gregpphoto wrote in post #8474362
If you shot it well, you won't need but a pinch of sharpening anyway.

Hardly. Bayer Filter.

Scottes wrote in post #8474409
Hardly. Bayer Filter.

?? I don't get it. What does the arrangement of of the RGB squares on the sensor (I had to wiki it) have to do with this?

Sensors have 2x as many green photosites than blue or green. The results from 2 green photosites, 1 red, and 1 blue one are merged - blurred, in a sense - to provide a single RGB pixel. 4 photosites blended/averaged/anti-aliased to form a single pixel.

To counter-act that blurring, you need to sharpen. Well, you should sharpen.

If a photosite captured an RGB value then you probably wouldn't need to sharpen.


I can't explain it any better, let alone more briefly, than the second post in this thread on another site (though there probably are better explanations with pretty pictures).
http://www.reduser.net​/forum/showthread.php?​t=29325