Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > Digital Photography > Unsharp Mask

Reply
Thread Tools

Unsharp Mask

 
 
=?ISO-8859-1?Q?BenOne=A9?=
Guest
Posts: n/a
 
      10-18-2004
Hi all,

I've read a few magazine tutorials about the Unsharp Mask feature in Photoshop
and they obviously make some assumptions about the image resolution you are
dealing with, but they don't say what that resolution is or how to translate
their recommended settings to your file resolution/print size.

They generally recommend an 'amount' of 150-200%, a 'radius' of 1 to 1.5, and a
threshold of up to three to reduce sharpening of jpeg artifacts.

I think those recommendations are based on 3 or 4 megapixel images, but I like
to resize my pictures to 600ppi which is considerably more than the 4 megapixel
source file my camera produces if I'm printing an 8x10.

Can someone recommend what USM settings to use for such large files?

Is there a relationship between the image ppi and the 'radius' and 'threshold'
USM settings?

Many thanks for any help.

I have tried just playing with the settings to see what looks best, but it would
be nice to know some theory so I can cut down on the number of test prints/time
wasted.
--
Ben Thomas
Opinions, conclusions, and other information in this message that do not
relate to the official business of my firm shall be understood as neither
given nor endorsed by it.

 
Reply With Quote
 
 
 
 
Tony
Guest
Posts: n/a
 
      10-19-2004
No one can recommend a setting. IT will depend on the picture and on the
observer. The recommendations you find are simply starting points and very
generalized.

--
http://www.chapelhillnoir.com
home of The Camera-ist's Manifesto
The Improved Links Pages are at
http://www.chapelhillnoir.com/links/mlinks00.html
A sample chapter from "Haight-Ashbury" is at
http://www.chapelhillnoir.com/writ/hait/hatitl.html

"BenOne©" <(E-Mail Removed)> wrote in message
news:dgh1lc.7p5.ln@192.168.11.2...
> Hi all,
>
> I've read a few magazine tutorials about the Unsharp Mask feature in

Photoshop
> and they obviously make some assumptions about the image resolution you

are
> dealing with, but they don't say what that resolution is or how to

translate
> their recommended settings to your file resolution/print size.
>
> They generally recommend an 'amount' of 150-200%, a 'radius' of 1 to 1.5,

and a
> threshold of up to three to reduce sharpening of jpeg artifacts.
>
> I think those recommendations are based on 3 or 4 megapixel images, but I

like
> to resize my pictures to 600ppi which is considerably more than the 4

megapixel
> source file my camera produces if I'm printing an 8x10.
>
> Can someone recommend what USM settings to use for such large files?
>
> Is there a relationship between the image ppi and the 'radius' and

'threshold'
> USM settings?
>
> Many thanks for any help.
>
> I have tried just playing with the settings to see what looks best, but it

would
> be nice to know some theory so I can cut down on the number of test

prints/time
> wasted.
> --
> Ben Thomas
> Opinions, conclusions, and other information in this message that do not
> relate to the official business of my firm shall be understood as neither
> given nor endorsed by it.
>



 
Reply With Quote
 
 
 
 
Michael A. Covington
Guest
Posts: n/a
 
      10-19-2004

"BenOne©" <(E-Mail Removed)> wrote in message
news:dgh1lc.7p5.ln@192.168.11.2...

> Is there a relationship between the image ppi and the 'radius' and
> 'threshold' USM settings?


Yes, absolutely. As you note, if the image is going to be viewed in a form
that allows every pixel to be visible, then a good radius is 1.5 (or much
larger if you want a "dodging" rather than "sharpening" effect).

If the image is very large and will be viewed reduced or printed on a
high-res printer, use a proportionally larger radius.

I like to set a high percentage in order to preview what details are going
to be emphasized, and then turn it way down (like to 20%) for a more subtle
effect in the finished picture.



 
Reply With Quote
 
Hunt
Guest
Posts: n/a
 
      10-19-2004
In article <dgh1lc.7p5.ln@192.168.11.2>, http://www.velocityreviews.com/forums/(E-Mail Removed) says...
>
>Hi all,
>
>I've read a few magazine tutorials about the Unsharp Mask feature in

Photoshop
>and they obviously make some assumptions about the image resolution you are
>dealing with, but they don't say what that resolution is or how to translate
>their recommended settings to your file resolution/print size.
>
>They generally recommend an 'amount' of 150-200%, a 'radius' of 1 to 1.5, and

a
>threshold of up to three to reduce sharpening of jpeg artifacts.
>
>I think those recommendations are based on 3 or 4 megapixel images, but I

like
>to resize my pictures to 600ppi which is considerably more than the 4

megapixel
>source file my camera produces if I'm printing an 8x10.
>
>Can someone recommend what USM settings to use for such large files?
>
>Is there a relationship between the image ppi and the 'radius' and

'threshold'
>USM settings?
>
>Many thanks for any help.
>
>I have tried just playing with the settings to see what looks best, but it

would
>
>be nice to know some theory so I can cut down on the number of test prints/

time
>wasted.
>--
>Ben Thomas
>Opinions, conclusions, and other information in this message that do not
>relate to the official business of my firm shall be understood as neither
>given nor endorsed by it.


Ben,

I'll direct you to a Photoshop book that covers sharpening images in good
detail, Ben Wilmore's Adobe Photoshop CS (there are editions for other
versions) Studio Techniques, Adobe Press. I'd also urge you to let your
critical eye be your guide, rather than a one-size-fits-all approach to
Sharpening. I work with files up to 5GB in PS and Sharpening can be very
critical and worthwhile, but it's always on an image-by-image basis.

Hunt

 
Reply With Quote
 
David J. Littleboy
Guest
Posts: n/a
 
      10-19-2004

"Tony" <(E-Mail Removed)> wrote:

> No one can recommend a setting. IT will depend on the picture and on the
> observer. The recommendations you find are simply starting points and very
> generalized.


Really.

Still, there are some ideas. You can use smaller radius settings (try 0.5 to
0.7) and higher amount settings for digital images (although I presonally
currently prefer lower amount settings: I don't like to see halos and I
don't like it when USM makes the image seem a lot brighter). This is one of
the great advantages of digital over film: the low noise means you have more
flexibility in processing.

Set the USM dialog view to 200% or 300%, point at a sky or smooth area, and
bump up the threshold setting until the noise isn't aggravated. If you are
using a consumer camera at any ISO or a dSLR at ISO 400 or over, try
NeatImage or Noise Ninja as the first step.

<rant in response to the quoted recommendations in the original note>
JPEG artifacts that are aggravated by USM don't occur at the lowest
compression (highest quality) settings. If you have JPEG artifacts that are
visible (or visibly aggravated by sharpening) at 100% on the screen, you are
using much too high a compression setting. JPEG losses at high quality
consist of reduction in contrast in high contrast fine detail. If you have
to use JPEG in the camera or during your workflow, only use the highest
quality setting.
</rant>

FWIW, the Japanese bimonthly (A4 glossy color) landscape magazine really
likes heavy unsharp masking. I'm nearsighted and tend to grain sniff, so I
see the halos. But it really does help if you are viewing at 10 inches or
more from the page, especially for tree branches/leaves that aren't against
the sky, where there isn't much contrast to start with.

Always archive an _UNSHARPENED_ version of your images. A year from now, you
will have very different ideas of what you like in sharpening, and a year
from then, your preferences will change again.

David J. Littleboy
Tokyo, Japan

> "BenOne©" <(E-Mail Removed)> wrote in message
> news:dgh1lc.7p5.ln@192.168.11.2...
> > Hi all,
> >
> > I've read a few magazine tutorials about the Unsharp Mask feature in

> Photoshop
> > and they obviously make some assumptions about the image resolution you

> are
> > dealing with, but they don't say what that resolution is or how to

> translate
> > their recommended settings to your file resolution/print size.
> >
> > They generally recommend an 'amount' of 150-200%, a 'radius' of 1 to

1.5,
> and a
> > threshold of up to three to reduce sharpening of jpeg artifacts.
> >
> > I think those recommendations are based on 3 or 4 megapixel images, but

I
> like
> > to resize my pictures to 600ppi which is considerably more than the 4

> megapixel
> > source file my camera produces if I'm printing an 8x10.
> >
> > Can someone recommend what USM settings to use for such large files?
> >
> > Is there a relationship between the image ppi and the 'radius' and

> 'threshold'
> > USM settings?
> >
> > Many thanks for any help.
> >
> > I have tried just playing with the settings to see what looks best, but

it
> would
> > be nice to know some theory so I can cut down on the number of test

> prints/time
> > wasted.
> > --
> > Ben Thomas
> > Opinions, conclusions, and other information in this message that do not
> > relate to the official business of my firm shall be understood as

neither
> > given nor endorsed by it.
> >

>
>



 
Reply With Quote
 
=?ISO-8859-1?Q?BenOne=A9?=
Guest
Posts: n/a
 
      10-19-2004
Tony wrote:

> No one can recommend a setting. IT will depend on the picture and on the
> observer. The recommendations you find are simply starting points and very
> generalized.
>


The "starting points" almost seem like perfect settings if I don't resize my
pictures to 600ppi but I don't think it's right to USM then resize.

--
Ben Thomas
Opinions, conclusions, and other information in this message that do not
relate to the official business of my firm shall be understood as neither
given nor endorsed by it.

 
Reply With Quote
 
Tetractys
Guest
Posts: n/a
 
      10-19-2004
BenOne wrote:

> Can someone recommend what USM settings
> to use for such large files?


<http://www.luminous-landscape.com/tutorials/understanding-series/understanding-usm.shtml>

> Is there a relationship between the image ppi
> and the 'radius' and 'threshold' USM settings?


Deke McClelland in "Photoshop 7 Bible: Pro Edition"
recommends 0.1 of radius value for each 15 ppi of
final image resolution, 25 to 50 percent sharpening
value, and leaves the threshold value up to your
experimentation. These are "start" values, and
he also recommends playing with them until you
like the results. Obviously, the lower the threshold
value, the more of the image USM affects.


 
Reply With Quote
 
Kevin McMurtrie
Guest
Posts: n/a
 
      10-19-2004
In article <dgh1lc.7p5.ln@192.168.11.2>, BenOne(C) <(E-Mail Removed)>
wrote:

> Hi all,
>
> I've read a few magazine tutorials about the Unsharp Mask feature in
> Photoshop
> and they obviously make some assumptions about the image resolution you are
> dealing with, but they don't say what that resolution is or how to translate
> their recommended settings to your file resolution/print size.
>
> They generally recommend an 'amount' of 150-200%, a 'radius' of 1 to 1.5, and
> a
> threshold of up to three to reduce sharpening of jpeg artifacts.
>
> I think those recommendations are based on 3 or 4 megapixel images, but I
> like
> to resize my pictures to 600ppi which is considerably more than the 4
> megapixel
> source file my camera produces if I'm printing an 8x10.
>
> Can someone recommend what USM settings to use for such large files?
>
> Is there a relationship between the image ppi and the 'radius' and
> 'threshold'
> USM settings?
>
> Many thanks for any help.
>
> I have tried just playing with the settings to see what looks best, but it
> would
> be nice to know some theory so I can cut down on the number of test
> prints/time
> wasted.


I don't think there's any general rule for use. My primary use for
Unsharp Mask is to compensate for haze using a large radius and small
amount. I've found that my camera's own sharpening is very well tuned
to the CCD. Adding a 200%, 1.5 pixel sharpening to my photos would ruin
them.

Unsharp Mask can be used to boost the usable resolution of a dithered
printer. It's tricky work and only experimentation will find the right
amount. It varies by image type, image resolution, printer type,
printer driver, and paper type. With modern drivers using smarter
dithering algorithms and finer dithers, the gain from doing so much
tedious tuning is becoming small.
 
Reply With Quote
 
=?ISO-8859-1?Q?BenOne=A9?=
Guest
Posts: n/a
 
      10-19-2004
David J. Littleboy wrote:


> <rant in response to the quoted recommendations in the original note>
> JPEG artifacts that are aggravated by USM don't occur at the lowest
> compression (highest quality) settings. If you have JPEG artifacts that are
> visible (or visibly aggravated by sharpening) at 100% on the screen, you are
> using much too high a compression setting. JPEG losses at high quality
> consist of reduction in contrast in high contrast fine detail. If you have
> to use JPEG in the camera or during your workflow, only use the highest
> quality setting.
> </rant>


Unless you are me, and have a Kodak DX6490 with JPEG quality choice, and no
other file formats to choose from.

>
> FWIW, the Japanese bimonthly (A4 glossy color) landscape magazine really
> likes heavy unsharp masking. I'm nearsighted and tend to grain sniff, so I
> see the halos. But it really does help if you are viewing at 10 inches or
> more from the page, especially for tree branches/leaves that aren't against
> the sky, where there isn't much contrast to start with.
>
> Always archive an _UNSHARPENED_ version of your images. A year from now, you
> will have very different ideas of what you like in sharpening, and a year
> from then, your preferences will change again.
>
> David J. Littleboy
> Tokyo, Japan


Thanks for the tips David.


--
Ben Thomas
Opinions, conclusions, and other information in this message that do not
relate to the official business of my firm shall be understood as neither
given nor endorsed by it.

 
Reply With Quote
 
=?ISO-8859-1?Q?BenOne=A9?=
Guest
Posts: n/a
 
      10-19-2004
Hunt wrote:

> I'll direct you to a Photoshop book that covers sharpening images in good
> detail, Ben Wilmore's Adobe Photoshop CS (there are editions for other
> versions) Studio Techniques, Adobe Press. I'd also urge you to let your
> critical eye be your guide, rather than a one-size-fits-all approach to
> Sharpening. I work with files up to 5GB in PS and Sharpening can be very
> critical and worthwhile, but it's always on an image-by-image basis.
>
> Hunt
>


Thanks Hunt. I'll see if I can find that book.
--
Ben Thomas
Opinions, conclusions, and other information in this message that do not
relate to the official business of my firm shall be understood as neither
given nor endorsed by it.

 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Unsharp mask on luminance channel in lab mode? no Digital Photography 3 06-17-2004 02:30 AM
Unsharp mask Daniel Dravot Digital Photography 4 04-05-2004 07:30 PM
Unsharp mask settings Onepercentf Digital Photography 47 01-14-2004 06:39 PM
Using the unsharp mask in Nikon Capture 3.0 Paddler Digital Photography 1 10-14-2003 12:21 AM
PS 7 - Unsharp Mask Settings FK Digital Photography 4 09-05-2003 03:52 PM



Advertisments