•Every image needs Sharpening.
•You cannot sharpen an out of focus image.
•Start with a sharp image and sharpen from there.
You will be amazed…
The name “Unsharp Mask” comes from an old-school analog technique where you created a duplicate negative that was slightly out of focus (unsharp) and then sandwiched it together (mask) with your original negative to make your print. The magical result was increased contrast around edges, creating the illusion of greater visual sharpness.
Objective:
•To explore the many sharpening techniques and to see firsthand what technique works best with different types of images
•To analyze and draw conclusions from the examples created
Overview:
•Choose ONE image to sharpen
•The image should be color corrected and cleaned up before sharpening
•Save As, flatten the file, size the file
(2160px on the longest size, 240ppi)
•For each sharpening technique create a duplicate file of that one image and apply the technique
•Save files as a .psd, include layers if technique does not require flattening.
TitleFile: Bold.psd (ex: original.psd, lum.psd)
1) Original image not sharpened (you do not need a duplicate layer for this file)
2) Unsharp mask
3) Lab Sharpening
4) Luminosity Sharpening
5) Layer Sharpening
6) High Pass Sharpening
7) Portion Sharpening (one area of the image sharpened)
•Turn in a typed page discussing your conclusions of the technique that worked best on your image and why.
File specs:
•2160 pixels, longest side
•240ppi
•Adobe RGB 1998
•8 bit file-.psd
•Sharpening is the last step before printing.
•Make a duplicate file.
•Size the file for printing.
•Then apply the desired sharpening technique.
•Sharpening will affect the contrast, making the image more contrasty
•How will sharpening affect the noise or grain in the image?
The Unsharp Mask creates a light/dark halo
-Amount – is the intensity of the halo; The pixels being pushed to extremes of white and black.
-Radius – is the width of the halo, wider the halo the more obvious the effect.
-Threshold – acts as a damper holding back noise or grain from being exaggerated
An Exercise Before Sharpening a Real Image:
•Open Photoshop and create two adjacent gray blocks
(it doesn’t matter what size).
•The left hand block should have the RGB value of 86, 86, 86 (in Photoshop, doubleclick on the foreground color in the tool palette, then enter those values directly into the RGB section of the Color Picker that appears). •The right hand block should have the RGB value of 43, 43, 43. Be sure that these blocks touch one another, and that you’ve turned off any anti-aliasing options in the tools you used to create them.
•Zoom way in on your image (500-1000%). You want to see the transition line between the two blocks clearly, so place it in the middle of your window.
•Photoshop: Filter->Sharpen->Unsharp Mask).
Select Unsharp Mask from the Filters menu and set starting values of 100 for Amount, 2 for Radius, and 0 for Threshold.
Amount: determines the aggressiveness of the “sharpening” action. With your simple two-gray image, try amounts of 100, 200, and 400 (make sure the Preview box is checked in the Unsharp Mask dialog so that you see the changes as you make them; you should also be viewing at Actual Pixels size). What you should see is that as the amount is increased, the colors of the new edges get more exaggerated. In other words, the light line that gets added on one side of the boundary gets lighter with each increase, the dark line on the other gets darker (though that’s often more difficult to see).
Radius: determines how wide an area at the transition is affected. Try increasing the Radius to 4 and 8, and you’ll see that area that is modified at the transition widens. Note, too, that the further away from the actual transition point you get, the less the Amount is applied.
Threshold: determines how much difference there must be between two adjacent pixels before any change is made. In our simple example, you’ll have to enter very high numbers before you see how this works (try 25, 50, and 100). Note that threshold and radius interact a bit. With a Threshold of 100 and a Radius of 1 or less, almost nothing changes, but if you increase the Radius, you’ll start to see the effect again.
If you found this exercise helpful, go check out the rest of the article.
http://www.bythom.com/sharpening.htm
The Sharpening Starts Here:
Always Duplicate your background layer. If you over-sharpen you can reduce the opacity of your sharpen layer.
1) Bring your image to 100% magnification on screen (Double click the zoom tool) use the move tool (hand) to scroll around to an area you can see the sharpening effect.
2) Filter – Sharpen - Unsharp Mask
With your image at 100% magnification experiment with the numbers and see the effects. All Images will have different settings. For my images I usually use an Amount setting between 50-100, the Radius 1-4 and the Threshold 0-3. Some people push this up to 5. You will find that different types of images have different sharpening parameters. I have seen others who swear by a totally different approach. Whatever works… this is our starting point.
Lab Sharpening
1) Open RGB file
2) Image – Duplicate
3) Click OK
4) Image – Mode – Lab Color
5) Channels palette – click the lightness channel
It will then be highlighted
6) Filter – sharpen – Unsharp Mask filter
At this point you will only be sharpening the black and white lightness channel avoiding the problem color
halos that pop up in the RGB sharpening approach.
7) Image – Mode – RGB Color
Luminosity Sharpening
1) Open RGB file
2) Image – Duplicate
3) Click OK
4) Filter – sharpen – Unsharp Mask filter
5) Edit – Fade Unsharp Mask
6) In the dialogue box change MODE to Luminosity
7) Click OK
The sharpening is now only applied to the luminosity not to the color data
Layer Sharpening
This avoids noise and color shifts
1) Open RGB file
2) Image – Duplicate
3) Click OK
4) Duplicate background layer
(Command – J)
5) Change the blend mode of the duplicated layer to Luminosity
6) Filter – Sharpen – Unsharp Mask Filter
7) Duplicate the sharpened luminosity layer (Command – J)
8) Filter – Blur – Gaussian Blur
-enter a pixel setting of “3”
-click OK
The blur takes care of exaggerated noise and halos from sharpening
9) Change the mode from Luminosity to Color, this gets rid of the blur
10) For this exercise leave layers, when printing flatten the file
High Pass Sharpening
1) In the Layer palette select your Background Layer and create a duplicate.
(Command “J”)
2) With this new layer highlighted go to the menu and select Filter – Other – High Pass.
Set the Radius to 10 and click OK. Zoom into your image to 50% or 100% so you canbetter see what you’re going to do next.
3) Go back to the Layer Palette and select Hard Light, Soft Light or Overlay from the
Blend modes drop down menu. Which do you like, me soft light
4) In the Layers Palette go to the Opacity Slider and select a level of sharpening that
seems best to you.
-Some believe you should move the radius slider to the first point you see color information, try this, experiment.
Applying sharpening to a Portion of the image
1) open an image
2) make a duplicate layer of the background
3) sharpen the background copy
3) Click the layer mask icon
4) Depending on what you want to sharpen? (less of the image you can command “I” to hide the sharpened layer and paint with white in the area you want sharpened) or do not inverse and paint away with black where you do not want sharpening
•When painting on a layer mask remember
•Black conceals
•White reveals
Kelby Generic Unsharp Mask #’s
LOW
amount – 100
radius – 1
threshold – 10
edit – fade unsharp mask – mode – luminosity
MEDIUM
amount – 85
radius – 1
threshold – 4
edit – fade unsharp mask – mode – luminosity
HIGH
amount – 120
radius – 1
threshold – 3
edit – fade unsharp mask – mode – luminosity
I have these set up as actions to quickly sharpen for the internet, etc.
ANOTHER Sharpening start POINT:
set the radius to be about 1/2 visually from the amount and threshold
ex:(these are just sample numbers)
amount 60%
radius about 3.0
threshold 0
