| Author | Thread |
|
|
08/30/2005 11:35:45 AM · #1 |
Just a couple of minutes ago, I found an explanation as to how the unsharp mask sharpens. An easy to understand explanation which also explains what radius, amount and threshold actually mean and do. I read this explanation in the book Grokking the Gimp, chapter 6.4 on sharpening. Though this book is on The Gimp, the free image editing program, this function is the same as the unsharp mask in Photoshop.
A couple of warnings....This explanation is a teeny bit technical...you need to know what a pixel is, what pixel values are, how pixel values are related to contrast and you are set.
Hope some other people find this useful too.
Sups
|
|
|
|
08/30/2005 11:58:50 AM · #2 |
Lovely tutorial. The link leads to the book itself, you want chapter 6.4.1 for the USM particulars.
Looks to me like the book is a very good read for anyone who wants to understand the basic principles of image manipulation, regardless of the program they use. The principles are all the same.
R.
Message edited by author 2005-08-30 13:54:31.
|
|
|
|
08/30/2005 12:50:06 PM · #3 |
Thanks for the chapter info. I am trying to read it as of now. Will probably keep coming back to it.
|
|
|
|
08/30/2005 01:05:02 PM · #4 |
Originally posted by bear_music:
Lovely tutorial. The link leads to the book itself, you want chapter 4.1 for the USM particulars.
Looks to me liek the book is a very good read for anyone who wants to understand the basic principles of image manipulation, regardless of the program they use. The principles are all the same.
R. |
6.4.1...but yeah, this is a great read that, as Robert said, can benefit all photographers.
I'd like to know more about how this worked in the darkroom...
Message edited by author 2005-08-30 13:11:15. |
|
|
|
08/30/2005 01:48:49 PM · #5 |
Thanks for the link. I've always wondered how USM worked.
Re the Q about USM in the darkroom... I googled and got this
"To create an unsharp mask in a wet darkroom one creates a blurred negative of the original, then overlays the two, then creates a final print from that." (USM link)
It seems to correspond closely to the digital USM technique, but never having developed anything in a real darkroom I don't know for sure.
Message edited by author 2005-08-30 13:49:32. |
|
|
|
08/30/2005 01:55:23 PM · #6 |
Originally posted by thatcloudthere:
Originally posted by bear_music:
Lovely tutorial. The link leads to the book itself, you want chapter 4.1 for the USM particulars.
Looks to me liek the book is a very good read for anyone who wants to understand the basic principles of image manipulation, regardless of the program they use. The principles are all the same.
R. |
6.4.1...but yeah, this is a great read that, as Robert said, can benefit all photographers.
I'd like to know more about how this worked in the darkroom... |
oops. dropped a digit. fixed. thanx.
R.
|
|
|
|
08/30/2005 03:02:28 PM · #7 |
bump - for anyone who might be interested.
|
|
Home -
Challenges -
Community -
League -
Photos -
Cameras -
Lenses -
Learn -
Help -
Terms of Use -
Privacy -
Top ^
DPChallenge, and website content and design, Copyright © 2001-2025 Challenging Technologies, LLC.
All digital photo copyrights belong to the photographers and may not be used without permission.
Current Server Time: 09/18/2025 05:13:02 PM EDT.
