Notes on Sharpening © Davide Barranca. Rev. 1.0.1 - January 2009

1. Introduction

This article is a work in progress collection of personal notes on the subject of sharpening; I’m no digital image processing scientist so, even though I like to play with theoretical problems, I try to find my answers within Photoshop (as I suppose they all do in Dan Margulis’ Color Theory Yahoo group, to which attention I first would like to turn this one). Chances are that I won’t be rigorous too, my aim is to better understand the subject and share my findings with people who would like to integrate them, or simply give a feedback on the techniques exposed. If you’re not interested in all the (very trivial indeed) math and graphs, feel free to skip to the how-to sections: nevertheless, I hope everything will be food for thoughts.

What I'm suggesting with this article is, among the rest, the possibility to target with appropriate sharpening different image features, even if they belongs to the same spatial frequency range (plus an experimental approach to high-radius low-amount sharpening). Then I'm showing how to use bilateral and mixed pyramid decompositions to modulate the sharpening within all the image frequencies.

(Fig. 1.1) Before and after version, applying some of the tecniques exposed in this article.

• see also: Davide Barranca | ALCE - A Local Contrast Enhancer for Photoshop >

Comments

Add New Search

"Shadow/Highlights" clarification please George Machen 2009-01-07 01:58:49 > 8. Bilateral and WLS Pyramids > > ...Shadow/Highlights with SB (instead of GB) in its > “engine” gives the same halo-free look by the way... I don't have CS4. Are you saying that its Shadow/Highlights dialog now features an option to choose whether it uses Gaussian or Surface Blur? If not, what did you mean exactly in this statement? Thanks! (G-R-E-A-T write-up, Davide!) Reply

Davide 2009-01-07 22:53:37 Hi George, I'm glad you liked it! No, unfortunately there's no GB/SB option in CS4. But you can always custom build your Shadows/Highlights: for instance, create a curve adjustment layer to lighten the picture, then add a luminosity mask to it (or choose the channel that better suits the image needs and use it as a mask). Now you can experiment using GB and SB for blurring the mask: the first one gives you a standard Photoshop S/H feeling, while SB (as long as the algorithm doesn't reverse) shows less or no halos. Ciao, Davide Reply

Alexey Rybakov 2009-01-07 19:58:18 Thanks for nice article with informative illustrations and examples. I'll glad to read more if you'll develop this farther. Reply

Re: "Shadow/Highlights" clarification please Stephen Marsh 2009-01-08 12:48:48 Thank you Davide, this is a great exploration, I am eagerly awaiting some actions! George, I presume that Davide is referring to manually simulating what the Shadows/Highlights command does. Dan Margulis described a method for this and one of the Applied Color Theory list members created an action. This action is available to list members from the files section. Margulis PSU ON2004.atn http://tech.groups.yahoo.com/group/colo rtheory/files/ How to re-create the Shadow/Highlight effect of Photoshop CS as described by Dan Margulis in the Oct/Nov issue of Photoshop User titled "Making Two Ends Meet", pg. 44-47. Regards, Stephen Marsh http://members.ozemail.com.au/~binaryfx/ Reply

Bravissimo !!! Andrea Baldini 2009-01-08 23:02:13 Devo dire che é una roba incredibile ! Davvero superba la genialità del progetto, non avevo mai visto nulla di simile! Complimenti anche per le illustrazioni realizzate molto bene. Spero che l' articolo venga tradotto anche in italiano. Complimenti ancora, Saluti Andrea Baldini Reply

good work Jack 2009-02-10 23:13:44 I'd love to test the actions when you create those. Also it would be nice to see samples on photographs as apposed to the painting your using here. It's difficult to see the sharpening. Reply

thank you! Timo Kirves 2009-03-14 17:51:02 Dear Davide, The whole series of your techniques open dramatically better chances to succesful fine art photographic prints with todays inkjet printers. I work as a photographer and instructor in Helsinki, Finland, working on both own and colleagues´photographic prints. Thank you for shearing this work of yours with the rest of community. Best Timo Kirves Reply

Davide 2009-03-14 22:48:29 Dear Timo, thank you very much for your comment, knowing that some of my thoughts may help someone out there getting better results and enjoying his pictures is a great reward for me. I wish I had more time to explore other interesting topics - I've something about local contrast in mind but I'd like to dig a bit deeper before publishing. Kind regards, Davide Reply

http://www.hyperugg.com cheap ugg classic cardy boots 2010-01-03 06:30:33 20100103c1sys this is because they are universal  link:http://www.hyperugg.com/ugg-classic-cardy-c- 43.html bailey button and full of choices,colour and gumboot tailor,has made the height of such a basic any women's clothing. you don't want to exchange some coffee or black,you can use a pair of ugg boots in almost any color you want.let people know you are here,and then buy a pair of cheap ugg boot,of course,you can choose the discount link:http://www.hyperugg.com/ugg-classic-tall-c-6 6.html.in boots were submitted for many length,concise,medium or long,you don't just show their jeans,you can actually consume a brace and rapid link:http://www.hyperugg.com/ugg-classic-tall-c-6 6.html dress and support. Reply

cheap ugg classic cardy boots 2010-01-03 06:30:48 20100103c1sys Wear discount {{[cheap ugg classic cardy boot->http://www.hyperugg.com/ugg-classic-cardy-c- 43.html]}} This WinteStep into this winter with the{{[cheap ugg tall boots->http://www.hyperugg.com/ugg-classic-tall-c- 66.html]}}.Features a molded rubber Ugged outsole for traction and slip resistance.High quality,genuine sheepskin upper with premium fleece lining absorbs moisture and keeps your feet dry and comfortable in both warm and cold climates. As with all the boots from Ugg Australia,the{{[ugg cardy boots on sale->http://www.hyperugg.com/ugg-classic-cardy-c- 43.html]}} can be easily broken in and so mold well to one's feet. UGG Classic Tall Boots In fact it is recommended that when wearing these boots or any {{[discount ugg classic tall boots->http://www.hyperugg.com/ugg-classic-tall-c- 66.html]}} for that matter one should go bare footed. Reply

http://www.shoesinter.com/ ugg classic cardy sale 2010-01-05 09:36:51 201001051sys All for one, one for all. Other men live to eat, while I eat to live. Easy come, easy go. Love rules his link:http://www.shoesinter.com/ugg-classic-cardy- c-66.html kingdom without a sword. We soon believe what we desire.The darkest hour is link:http://www.shoesinter.com/ugg-classic-short- c-69.html that before the dawn. The longest day has an link:http://www.shoesinter.com/ugg-bailey-button- c-75.html end. Living without an aim is like sailing without a link:http://www.shoesinter.com/ugg-classic-tall-5 812-mettlic-gold-boots-p -1643.html compass. A bird in the hand is worth two in the bush. One swallow does not make a summer. A man may lead a horse to the link:http://www.shoesinter.com/ugg-ultra-tall-c-8 9.html water, but he cannot make it drink.   One cannot eat one's cake and have it. Time is link:http://www.shoesinter.com/ugg-ultra-short-c-&n... Reply

dsadsad 2010-01-21 07:49:06 Do you like shipping?Do you want to let yourself be more appealing ?Are you beckoning because of the vogue and elegant link:http://www.eurluxury.com/ and link:http://www.bootsluxury.com/classic-tall-boot s-c-9.html.Do you envy others because they have the link:http://www.handbagspop.com/,but becauce the exorbitant price you shrink back at the sight? Now it is not only a dream to wear the link:http://www.christianlouboutinmy.com link:http://www.uggbootsems.com/ and carry the link:http://www.handbagsboots.com/,and you can buy those things in link:http://www.handbagcom.com store. The cheap price of link:http://www.handbagcom.com/ and link:http://www.handbagcom.com/ is beyond your imagination,and the link:http://www.christianlouboutinmy.com in the link:http://www.handbagcom.com/christian-loubouti n-shoes-c-101.html are all quality goods.Don't hesitate and wear the link:http://www.bootsluxury.com/cla... Reply

replica watches replica watches 2010-01-22 04:46:16 gennanv0122 link:http://www.watches9.com| link:http://www.watches9.com link:http://www.watches9.com link:http://www.hermes-luxury.com link:http://www.hermes-luxury.com link:http://www.hermes-luxury.com link:http://www.iamreplica.com link:http://www.omega-watches-replica.com| link:http://www.replica-cartier-watches.com| link:http://www.rolex-watches-replica.com link:http://www.breitling-watches-replica.com| link:http://www.watches9.com/A-Lange-&-Sohne_4.ht ml| link:http://www.watches9.com/Bell-&-Ross_8.html link:http://www.watches9.com/Tag-Heuer-Watches_41 .html link:http://www.watches9.com/Iwc-Watch_25.html| link:http://www.watches9.com/Longines_28.html| link:http://www.watches9.com/Louis-Vuitton-Watche s_29.html link:http://www.watches9.com/Rolex-Watches_399.ht ml link:http://www.watches9.com/A-Lange-&-Sohne_4.ht ml| link:http://www.watches9.com/Breitling-Watches_10 .html| link:http://www.watches9.com/Bvlgari-Wat... Reply

fghgj replica handbags 2010-01-26 04:53:43 No matter what season, what places we will not let you lose youth and beauty.Because we have the link:http://www.christianlouboutinmy.com by the top designers and the most fashionable link:http://www.handbagcom.com. You will be more confidence Becauce of the comfortable,warm link:http://www.bootsluxury.com/classic-short-boo ts-c-12.html and link:http://www.eurluxury.com/,the unique charm of link:http://www.handbagcom.com/ and link:http://www.handbagspop.com/,will make you more confidence.We believe that the link:http://www.handbagsboots.com/ and link:http://www.handbagcom.com/christian-loubouti n-shoes-c-101.html will bring the super quality life for you,and we also believe that link:http://www.christianlouboutinmy.com and link:http://www.handbagcom.com/ will make you have a life jounery with happiness.there is always hope,let us believe the wonderful memroies about the link:http://w... Reply

http://www.buywholesalea.com Wholesale Nike AirForce 2010-02-05 04:21:32 Cheongsam wholesale athletic shoes wholesale shoe stores wholesale nike shoe wholesale jordan shoes jordan shoes sale wholesale nike cheap nike wholesale ugg ugg sheepskin boots wholesale ugg boots wholesale levis wholesale hoodies wholesale Wholesale Nike AirForce Nike AirForce 1 wholesale nike shoe nike shoe wholesale Wholesale Nike AF shoes nike cheap nike wholesale Nike AirForce Wholesale Nike AirForce 1 Wholesale Nike AF Reply

wow gold wow gold 2010-02-07 01:46:14 link:http://wowus.virgolds.com is one of the most important item when you like playing this game. There are many link:http://wowus.virgolds.com online stores where you can buy link:http://wowus.virgolds.com. If you are lucky, you can get link:http://wowus.virgolds.com at cheap price. link:http://wowus.virgolds.com can enhance your power. Reply

Write comment
Name:
Email:
Title:
Please input the anti-spam code that you can read in the image.

Powered by !JoomlaComment 3.26

3.26 Copyright (C) 2008 Compojoom.com / Copyright (C) 2007 Alain Georgette / Copyright (C) 2006 Frantisek Hliva. All rights reserved."