Sharpening is totally “Output” dependant. In other words we apply sharpening depending on how we will display that image. If it’s going to be displayed on screen we need to know how big a screen and what resolution the actual image will be. If we are printing the image, we need to know how it is being printed (Inkjet/Giclee’ or true photographic print/continuous tone) and how big. Sharpening for one use will not be correct for another. If we applied the same sharpening that we use for a 20 x 30 Giclee’ print on a 600 x 400 image on our Facebook page, that Facebook image would be way over-sharpened and full of sharpening artifacts.
One note before I continue on. If you have any aspiration of do Stock Photography, do not apply any sharpening to your images. You don’t know what the final use will be for that image and that should be left to the end user and their re-toucher/designer
Sharpening for print
Sharpening for print is dependant on print size and how it will be viewed. Thisis why I work with a Master Tiff or PSD file and then make Print JPEG copies depending on the size print I am making or having made. You can, if you don’t want to go this extreme, just make one print file but make it for what you expect the average large size print to be. Say 16” X 24” I print up to 40” x 60” and would rather do each size independently but that’s me.
Since sharpening is so size dependant, first we must look at that image correctly so that we can see in real time/ real size how our sharpening affects the image. So I will let you in on a little known or used property of Photoshop. “View> Print Size”. Now wait a minute you say, I’ve always known about that. You probably have. BUT did you know how to calibrate it or use it in practice?
This will take a measuring and a little calculating. Get a small tape measure or ruler and measure your monitor screen’s width Don’t just go by what the monitor says it is as in I have a 23” monitor that’s what it says on the box. That is the diagonal measurement, it was perpetrated by men, we always want things to seem larger than they are. So measure the width of the actual display area of your screen. In the case of my “22 inch “screen that measurement was `18.75”. Now find out what the horizontal resolution of your screen is set at. In Windows you can do that by right clicking on your desktop and go to properties. Macs…well you own a Mac so you should know everything (jealous laughter)
My resolution is 1680 x 1050; the first number is the width resolution. Now take that number and divide it by your width measurement 1680/ 18.75 = 89.6 pixels per Inch
We can round that so we have a Screen Resolution or 90 ppi. Write that number down. (Well, write YOUR number down)
Now open Photoshop. In your Preferences (Edit>Preferences) go to the Units and Ruler tab and under Screen Resolution put in that number (whatever yours works out to be) (don’t change the Print resolution number)
You have now calibrated your monitor to be the correct size so that if you have an 8 x 10” image displayed at print size, you will see it actual size. Go ahead measure it if you don’t believe.
Our next step is to size our image for the size print we will make. When we do this we will not be changing the actual file itself but rather just the document size. I know that sounds confusing but we won’t be altering the pixels at all, just how big the print will look on screen.
We do this by going to Image> Image Size
The first thing you need to do is UN-CHECK the box for “Resample Image” this will ensure that we don’t actually change the file. Then in the width and height areas put in the dimension for the print you want to make. In this case I choose to make a 30” x 20” print. One item to take note of though is the Resolution, this number will change as you change Print sizes the only time you need to worry about it is if that number falls below 100. Most print labs need at least a number of 100 to make an acceptable print.
Once you have you print size in, click OK. Now if you go up to View> Print Size, the size you see on screen is the actual size of the print that will be made.
With this view we now can make an accurate judgment on how sharp the image needs to be. It may by itself be plenty sharp and you may need to do nothing. If that is the case do just that, nothing. The less you do to an image, the better off you usually are. But if you find the image lacks the detail you want, then we need to move on to sharpening.
Sharpening –High Pass Sharpening -The Home Brew
As I stated earlier there are as many ways to do sharpening as there are ways to do HDR. Photoshop itself has about 6 sharpening method built into its filter menu. Lightroom has its own sharpening area. For me I like an alternative method known as High Pass Sharpening. I feel it has the most power and control and I think. It just looks good. If you like the built in sharpening then by all means use them, just make sure you view the images at the correct size as above to apply the right amount of sharpening. Smart Sharpening in Photoshop is probably the best built in
Start by duplicating your image in a layer. Layer > Duplicate layer. Now go up to Filter>Other>High Pass
Your image will turn all gray and this dialog box will pop up.
Start with a Radius of 2.0 and work from there. What we are looking for is just the edges of object since that is what sharpening deals with the contrast of edges. Move the control back and forth till you just see the fine edges of object. If you select too much the sharpening will be applied to areas beyond the edges resulting in haloing. Once you have your edges. Click OK.
With that layer selected go up to the Layer Blend mode where the drop down now says “Normal” drop down this list and here we have quite a few choices. The ones that are applicable are
- Soft Light
- Hard Light
- Vivid Light
Changing the blend mode will change the amount and the look of our sharpening. If I have an image with a lot of small detail, I will use Overlay, if my objects are larger I will use Vivid. But it totally depends on your image. There is not just one right answer. You can also vary the opacity of that layer if the look is right but the power is just too strong.
Play close attention to edges; look for telltale of over sharpening. haloing, white lines, color changes, color fringing. If it looks good, it is good
You can flatten the image a then Save as a JPEG to keep or send as a Print file for that image and that size with it’s own unique name. I usually don’t flatten the image because that allows me to go back and make changes to that sharpen layer later on if I so choose and I save the image as Tiff or PSD
That’s all there is to it.
Geez isn’t there an easier method?
Once again Peter, I didn’t think I needed a science experiment just to print a stupid picture! Well once again this is where we use the smarts of the software makers to take care of our problems and Nik Sharpener Pro 3.0 does just that. It does the calculating for you.
Nik Sharpener Pro 3.0
Nik Sharpener Pro 3.0 is two sharpeners built into one. It is a RAW Pre-sharpener if we just wanted to sharpen an image not knowing what our final output would be and want to make up for some general softness to our image. But then there is the more adaptive and useful part, The Sharpener Pro 3.0 Output Sharpener. This takes what you want to do with your image into consideration and pretty much guides you through the process. Just answer some simple question in drop down boxes and it will do the thinking for you.
The first thing it asks in the right Adjustment area is: What do you want to do with this image?
- Inkjet Print (Giclee type Photographic Print)
- Continuous Tone print (photographic type print)
- Halftone (Print Press)
So you tell it what you want to do. I want to make a continuous tone print. Select that and now you are posed with other questions you answer
- Viewing Distance
- Yes viewing distance for a print can matter. The closer you view something the less sharpening it may need. If it is a print held in your hand or a print on the wall this can vary. (I found that the Auto setting worked well)
- Printer resolution: If you know this then enter that in, I know my print lab uses 250 ppi. If you don’t know , use 300
- Image Height and Width, Enter in the print size you want to make and it will apply enough sharpening for that size. This is a substitute for viewing at print size like we did for the High Pass Sharpening. It is also what the AUTO setting for viewing distance takes into consideration.
Answer the questions and you are done. You do have the options to apply more or less sharpening in the section below. But for the almost all situations the software does a great job of applying sharpening for your image.
Another cool thing is the ability to apply Selective sharpening. If you remember from our post about Bokeh, you don’t always want sharpening accross the entire image espcially parts that are supposed to be out of focus. The use of control points in Nik Sharpener Pro 3.0 allows you to just apply sharpening to selective areas of an image
And that’s it; you can either do the work yourself or let software work for you.
Here are some examples using 100% Crops to see the effects of Sharpening
This is no sharpening (SOOC)
This is High Pass Sharpening
This is The Nik Sharpening
And yes there is a difference in the two sharp methods, mine was as my eye saw, the other was as the program saw fit.
Sometimes as we sharpen an image it makes the noise in an image more apparent. In most cases if you find unacceptable noise in your image, you should De-Noise the image before sharpening. Then you know about how much to sharpen the image. Bear in mind it kind of a back and forth thing and you are trying to find a happy medium. The noise reduction reduces sharpness and the sharpening makes noise more visible so sometimes you need to find a compromise.
Sharpening for the Web
So far we have discussed sharpening for print or large display on an LCD. Now let’s discuss sharpening for the web that actually is a two part process: Resizing an image (which reduces sharpness, and then sharpening that image. Even the process of re-sizing can affect how our image looks and its sharpness.
The first thing we need to know is what size will our image be displayed on the web. The last thing you want to have happen is for either a website (Facebook, Google + etc) to resize our image. Nor do we want our web-browser itself to resize the image. They use the worst possible resize method (Nearest neighbor) and make our images look even worse than just resizing does.
For this blog, I can post at 620 Pixels on the longest side, for my other portfolio blog, Petertellone.com I can post at 900 on the longest side. But because I can have people click on my images here for a better look, I do them at 900 pixels on the longest side too, Sacrificing a little in the blog display to make them look better in the large image (If I am doing a vertical image I keep it to 700 Pixels because that fits better when people view without scrolling)
Find the right size for your website/blog/social media and then resize to it.
In Photoshop To resize your image go to Image>Image Resize for the resize method choose Bi-cubic, Lightroom also use that method. Despite what you may have heard about web size images needing to be 72 ppi resolution, that number in the context of digital image has absolutely no bearing
Once resized now look at the image, this time using “Actual Pixels” since this is how the image will actually be seen. There no longer is a “Document size” for web images.
If the image has lost more sharpness than desirable then you will need to sharpen. I feel the High Pas ssharpening is over kill for sharpening for the web. Instead, this time I use one of Photoshop’s stock filters: Unsharp mask. I start with settings of Amount 40, Radius 1.8 and Threshold 1, varying these as I see fit.
Lightroom will do these operations upon exporting (resize/sharpen) you just don’t have as much control with those choices left to presets)
Or, once again you can use Nik Sharpener Pro 3.0, Choose display and vary the adaptive sharpening to your eye.
Save the image as a new file making sure to rename it something other than the original file name, such as Mydog_web.jpg and save it with enough compression to bring the file size to about 100K or smaller for fast load times. Too large and the image will take too long to load, Too small and the image will now have compression artifacts which look even worse than an unsharp image.
And there you have it. To recap
For print images
- Calibrate Photoshop for correct display size
- View at the actual print size
- Use eitherHigh Pass sharpening or Nik Sharpener Pro 3.0 Output based sharpening
- Save a copy as a Print file based on the print size
For web Images
- Resize the image properly and to the actual size it will be displayed on the website
- Use Unsharp mask or Nik Sharpener Pro 3.0 Output based sharpening
- Save as a web copy
Hope that helps