Sharpening a picture.

"Jj" wrote in message

I always thought that when someone wants to sharpen a picture to make it more clear, one would use the sharpen feature. However, I think this is wrong because every time I try to sharpen a picture it seems to make it worse.

Can anyone educate me on this.

—
Peace in Christ,

JJ
www.whychristianity.com

Yes, it’s the work of the Devil!
Believe me , I know, I work for him
Boo!

Stephan

"Jj" wrote in message

I always thought that when someone wants to sharpen a picture to make it more clear, one would use the sharpen feature. However, I think this is wrong because every time I try to sharpen a picture it seems to make it worse.

Can anyone educate me on this.

If the picture is worse then you have over-sharpened it. What settings are you using? I typically use 500%, .2 pixels 0 threshhold or 200%, .3 and 0.

—
Peace in Christ,

JJ
www.whychristianity.com

Unsharp Mask gives more control but yes sharpen tends to increase the contrast and can bring out grittyness so it is sort of less clean in that way. I wonder sometimes if a little blur before would help get rid of the grittyness, weird as it sounds.

It also increases the saturation so you might want to adjust that back down afterwards.

Jj wrote:

I always thought that when someone wants to sharpen a picture to make it more clear, one would use the sharpen feature. However, I think this is wrong because every time I try to sharpen a picture it seems to make it worse.

Can anyone educate me on this.

—
Peace in Christ,

JJ
www.whychristianity.com

Jj wrote:

I always thought that when someone wants to sharpen a picture to make it more clear, one would use the sharpen feature. However, I think this is wrong because every time I try to sharpen a picture it seems to make it worse.

Use Unsharp Mask (USM), not Sharpen.
Learn to use the "Threshold" slider in USM.

Can anyone educate me on this.

Any sharpen algorithm will create artifacts, since they all do locally enhance contrast and saturation. So noise etc. will get enhanced, too.

#The Threshold slider is for setting at which minimum local contrast USM will start to kick in.

(At a high threshold value, only the most contrasty features will get sharpened. At a low treshold value, every contrast (including noise) will get enhanced.)

#Radius: the finer the features that you want to sharpen, the smaller must be the radius.

Often you want to sharpen features in different magnitudes (pixelwise). For that you should do two subsequent USM passes, each with different "Radius" settings. But: the "Amount" value needs to be set pretty low in this situation (try amount values of e.g. 40% to 70% for each pass).

USM recipe:
1.) Set "Amount" way too high, e.g. 300% to 500%; set "Threshold" way too low (e.g. 0 Levels).

2.) Set "Radius" until you see a maximum sharpening effect on the features that you want to sharpen during this pass.

3.) Get a good "Threshold" value, trying to balance desirable sharpening and unwanted noise.

4.) Lower the "Amount" value until acceptable. If in doubt, prefer a too low value – you can always sharpen more, but you can’t reverse the effects of sharpening.

A very useful technique is to first create a luminance mask of the image, find edges [Filter>Stylize>Find Edges], increase contrast of the mask, then use this mask on the image (or a selection made off that mask) while Unsharp Masking.

That approach allows you to selectively sharpen only the edges, and you won’t enhance noise in rather homogeneous areas.
On some tutiorial sites this is called "Two pass sharpening".

www.whychristianity.com

www.whychristianFundamentalistGeorgeBushIsATerrorist.com

Regards,
Fred

—
the gloomy future of computing: TCPA/TCG/Palladium/NGSCB/DRM FAQ

– english (original) http://www.cl.cam.ac.uk/~rja14/tcpa-faq.html – deutsch (transl.) http://moon.hipjoint.de/tcpa-palladium-faq-de.html

Thanks everyone for your help in this matter. I will try it and see what the outcome is and if I have anymore problems I will repost.

Peace is in Christ.

JJ

"Fred" wrote in message

Jj wrote:

I always thought that when someone wants to sharpen a picture to make it more clear, one would use the sharpen feature. However, I think this is wrong because every time I try to sharpen a picture it seems to make it worse.

Use Unsharp Mask (USM), not Sharpen.
Learn to use the "Threshold" slider in USM.

Can anyone educate me on this.

Any sharpen algorithm will create artifacts, since they all do locally enhance contrast and saturation. So noise etc. will get enhanced, too.
#The Threshold slider is for setting at which minimum local contrast USM will start to kick in.

(At a high threshold value, only the most contrasty features will get sharpened. At a low treshold value, every contrast (including noise) will get enhanced.)

#Radius: the finer the features that you want to sharpen, the smaller must be the radius.

Often you want to sharpen features in different magnitudes (pixelwise). For that you should do two subsequent USM passes, each with different "Radius" settings. But: the "Amount" value needs to be set pretty low in this situation (try amount values of e.g. 40% to 70% for each pass).
USM recipe:
1.) Set "Amount" way too high, e.g. 300% to 500%; set "Threshold" way too low (e.g. 0 Levels).

2.) Set "Radius" until you see a maximum sharpening effect on the features that you want to sharpen during this pass.

3.) Get a good "Threshold" value, trying to balance desirable sharpening and unwanted noise.

4.) Lower the "Amount" value until acceptable. If in doubt, prefer a too low value – you can always sharpen more, but you can’t reverse the effects of sharpening.

A very useful technique is to first create a luminance mask of the image, find edges [Filter>Stylize>Find Edges], increase contrast of the mask, then use this mask on the image (or a selection made off that mask) while Unsharp Masking.

That approach allows you to selectively sharpen only the edges, and you won’t enhance noise in rather homogeneous areas.
On some tutiorial sites this is called "Two pass sharpening".

www.whychristianity.com

www.whychristianFundamentalistGeorgeBushIsATerrorist.com
Regards,
Fred

—
the gloomy future of computing: TCPA/TCG/Palladium/NGSCB/DRM FAQ
– english (original) http://www.cl.cam.ac.uk/~rja14/tcpa-faq.html – deutsch (transl.) http://moon.hipjoint.de/tcpa-palladium-faq-de.html

There are two other methods that help me with sharpening.

1. Switch to Lab mode and then go to channels; then go to Channels and select the Lightness channel. Sharpen that to your liking. Then return back to RGB. I

2. Sharpen your image using the Unsharp Mask. Then immediately afterward go to Edit -> Fade Effect and change the mode to luminosity.

These two methods work well without effecting the color.

Hope this helps,
Sweet-P

"Jj" wrote in message

I always thought that when someone wants to sharpen a picture to make it more clear, one would use the sharpen feature. However, I think this is wrong because every time I try to sharpen a picture it seems to make it worse.

Can anyone educate me on this.

—
Peace in Christ,

JJ
www.whychristianity.com

High Pass/Hard Light method of sharpening
Make a duplicate of your image or layer. It will appear on top of the original. Select Hard light as the blending mode. Choose from the filter menu "other" then "High pass". You can use any amount you want, but usually about 4-6 pixels is plenty. Then you probably would want to reduce the opacity of the duplicated layer to about 75 percent, and merge the two. You haven’t even added any unsharp masking yet, and already the image is much sharper. Now you can add just a touch of unsharp masking. This way, you won’t get nearly as much grain or artifacts as you would if you just used the unsharp masking filter. Also, if you are working with a color image, you can REALLY get a lot of different shades of red to appear in an image that would otherwise just be one or 2 shades. This is really nice in flower images, when reds tend to blur into just a couple shades.

Note: it was suggested you might need to desaturate the high pass layer of all color to avoid a color shift in some portions of your image. Do this
step after you have choosen the Hard Light blending mode and adjusted your opacity.

Note: also suggested you might try Soft Light blending mode for some images. HighPass/HardLight article was in Design Graphics #50, author Carl Stevens…

Merry Christmas, ~Dr. J.

Wow, this technique is super! I just tried it on a couple of images, and it is wonderful. No loss of quality and beautifully sharp image….thanks so much for sharing this. What is the complete title of the book you are referencing to. I would love to get a copy of it.

Sweet-P

"Dr. J. Smith" wrote in message

High Pass/Hard Light method of sharpening
Make a duplicate of your image or layer. It will appear on top of the original. Select Hard light as the blending mode. Choose from the filter menu "other" then "High pass". You can use any amount you want, but usually about 4-6 pixels is plenty. Then you probably would want to reduce the opacity of the duplicated layer to about 75 percent, and merge the two. You haven’t even added any unsharp masking yet, and already the image is much sharper. Now you can add just a touch of unsharp masking. This way, you won’t get nearly as much grain or artifacts as you would if you just used the unsharp masking filter. Also, if you are working with a color image, you can REALLY get a lot of different shades of red to appear in an image that would otherwise just be one or 2 shades. This is really nice in flower images, when reds tend to blur into just a couple shades.

Note: it was suggested you might need to desaturate the high pass layer of all color to avoid a color shift in some portions of your image. Do this
step after you have choosen the Hard Light blending mode and adjusted

your

opacity.

Note: also suggested you might try Soft Light blending mode for some

images.

HighPass/HardLight article was in Design Graphics #50, author Carl Stevens…

Merry Christmas, ~Dr. J.

Wow, this technique is super! I just tried it on a couple of images, and

it

is wonderful. No loss of quality and beautifully sharp image….thanks so much for sharing this. What is the complete title of the book you are referencing to. I would love to get a copy of it.

Sweet-P

Hidy hi Sweet-P…
I came across said info on a totally unrelated search and saved it to try it out. I agree, it’s a super technique and you’re welcome. However when you asked where I got it from I couldn’t find the original source. What I did find out was that it was originally taken from a magazine out of Australia. I may have stepped on someone’s copyrighted toes by posting it in here but I can’t be sure as they do post downloads of their articles. Then again I didn’t find the one I posted here. So in the spirit of redemption (and unsolicited advertising) check these guys out at:

http://www.designgraphics.com.au

Thsi picture I was questioning about, I tried to post it with this post. Was is it not available for anyone to read. I see no attachments with this originial pos?

JJ
"Sweet-P" wrote in message

Wow, this technique is super! I just tried it on a couple of images, and

it

is wonderful. No loss of quality and beautifully sharp image….thanks so much for sharing this. What is the complete title of the book you are referencing to. I would love to get a copy of it.

Sweet-P

"Dr. J. Smith" wrote in message

High Pass/Hard Light method of sharpening
Make a duplicate of your image or layer. It will appear on top of the original. Select Hard light as the blending mode. Choose from the filter menu "other" then "High pass". You can use any amount you want, but usually about 4-6 pixels is plenty. Then you probably would want to reduce the opacity of the duplicated layer to about 75 percent, and merge the two. You haven’t even added any unsharp masking yet, and already the image is much sharper. Now you can add just a touch of unsharp masking. This way, you won’t get nearly as much grain or artifacts as you would if you just used the unsharp masking filter. Also, if you are working with a color image, you can REALLY get a lot of different shades of red to appear in an image that would otherwise just be one or 2 shades. This is really nice in flower images, when reds tend to blur into just a couple shades.

Note: it was suggested you might need to desaturate the high pass layer of all color to avoid a color shift in some portions of your image. Do this
step after you have choosen the Hard Light blending mode and adjusted

your

opacity.

Note: also suggested you might try Soft Light blending mode for some

images.

HighPass/HardLight article was in Design Graphics #50, author Carl Stevens…

Merry Christmas, ~Dr. J.

Thanks so much for the link. They have some neat tutorials there. I appreciate it 🙂

Sweet-P

"Dr. J. Smith" wrote in message

Wow, this technique is super! I just tried it on a couple of images, and

it

is wonderful. No loss of quality and beautifully sharp image….thanks

so

much for sharing this. What is the complete title of the book you are referencing to. I would love to get a copy of it.

Sweet-P

Hidy hi Sweet-P…
I came across said info on a totally unrelated search and saved it to try

it

out. I agree, it’s a super technique and you’re welcome. However when you asked where I got it from I couldn’t find the original source. What I did find out was that it was originally taken from a magazine out of

Australia.

I may have stepped on someone’s copyrighted toes by posting it in here but

I

can’t be sure as they do post downloads of their articles. Then again I didn’t find the one I posted here. So in the spirit of redemption (and unsolicited advertising) check these guys out at:

http://www.designgraphics.com.au

Thsi picture I was questioning about, I tried to post it with this post.

Was

is it not available for anyone to read. I see no attachments with this originial pos?

Jj,

Newsgroups were originally designed as discussion boards. They have since evolved into private and public, moderated and un-moderated, binary (for file sharing) and non-binary forums.

A binary newsgroup is the only type of newsgroup where it is appropriate to share files such as image files, mp3s, movies, and software. These newsgroups normally have the word "binary" or "binaries" in the name of the group. example: alt.binaries.jazz.mp3. Our newsgroup,
alt.graphics.photoshop is a NON binary newsgroup. It is also inappropriate to post using RTF (rich text format), HTML (hyper text markup language), html signatures or v-cards. The reasons for this are,
1. ISP’s are trying to save space on their servers and do not want to include many of the binary newsgroups on the net, so they will delete any posts that contain RTF, HTML or binary attachments. This means some people won’t ever see your original post.
2. Some of the news reader software out there is not capable of handling these items and will often lock up or crash.
3. It is established Usenet etiquette. In some newsgroups people often start long flame wars over this issue. To avoid this issue all together simply set your news reader to post original and reply messages in plain text only.

If you need to show an example put it on your web page or even one of those photo-sharing sites and post a link to it here.

~Dr. J