The following is a sample lesson from a previous version of Jim Miotke's Beginning Photography online photography course. Note: this lesson is no longer in Beginning Photography class - it is now a free sample.
Lesson #10: Scanning and Sharpening
In this lesson, we will first take an introductory look at scanners and scanning and then get a taste of what we can do with digital sharpening functions such as Photoshop's Unsharp Mask filter.
Even though this is only an overview of these topics, this lesson is a long one. There is simply no way to be brief when discussing digital options. There is so much ground to cover, we will simply have to roll up our sleeves and do our best.
Scanners come in two main flavors - flatbed scanners and what are called dedicated film scanners.
Epson Flatbed Scanner
Canon Dedicated Film Scanner
Most people, when they think of a scanner, picture a large flat device with a lid, like the one above left. You open up the lid, place your original on the glass, and scan away - much like a Xerox copier.
However, this is not the only kind of scanner around. Photographers with a little extra money to burn have another option - the dedicated film scanner.
Film scanners are smaller than flatbeds, more expensive, and designed to scan one slide or negative image at a time.
Some flatbed scanners can scan slides and negatives, with the help of what is called a transparency adapter. These can give you decent scans for Web display and emailing but are generally not the best for scanning images that you would like to print.
Regardless of which type of scanner you have, a few tips can help you maximize its potential.
What's Better to Scan: Film or Prints?
I prefer to scan film before settling for a scan of a print. Also, I mainly shoot slides and find them easier to handle than negatives when scanning. On the other hand, many people find that negatives produce much better looking scans than slides. Slides tend to look more contrasty when scanned - the brights often get too bright and the shadows get too dark.
As difficult as slides might be, though, the contrast problem is worse when scanning prints. Scanning prints is like making a copy of a copy, like taking a CD by your favorite musician and recording it to cassette tape. The results are okay but definitely not great.
Now, if you wanted to make another copy of this album, recording directly from the CD again would be much better than recording from the duplicated cassette. It is always better to make a copy from the original or "master" than it is to make a copy of a copy. The same principle applies to making copies of photographic images.
What About Resolution?
When it comes to getting images in a digital way, it is all about the size and flexibility of the chip - the scanning sensor - usually called a CCD.
There are two main things you need to keep in mind regarding resolution:
- Resolution can be calculated in many different ways. Some scanners ask you to tell them what you want as your final result, e.g. a 4" x 6" print or a 640 x 480 pixel image for emailing. Other scanners tell you the resulting file size that you will get if you scan at a certain resolution. Many give you all these options and let you choose. If that is the case, use these guidelines:
- For email or Web, keep it under 1000 pixels on the long end (or about 1-2MB file size)
- For prints, you never need to scan for a resulting image resolution of more than 300ppi; often 150ppi works just fine. Don't scan at 1440ppi just because your printer prints at that level - that kind of resolution is a completely different meaning of the word.
- But, at the same time, you do need BIG files for high-quality printing. Although you won't need more than 300ppi, you will need a 2400 x 3000 pixel image to do a nice 8" x 10" print - that is a pretty big file.
- There is no free lunch. You can't cheat with resolution and squeeze out more than your scanner can physically produce. Manufacturer's often talk about interpolated resolution, referring to the scanner's ability to fake higher resolution by "guessing" at how your image would look if it was much bigger. As you can guess, I am not a proponent of interpolation. Always work within the limits of your scanner - find out the optical resolution (look in your specs) and stay within that limit.
Remember, It Ain't Easy Scanning Things
High quality scanning, contrary to popular opinion, is really, really, really hard.
Agfa FotoLook Scanning Software Interface
Be patient with yourself as you begin to go down this path. The hardware aspect alone can involve everything from opening up your computer and inserting special "cards" to tinkering with jumper switches to messing with "scuzzy" (SCSI) cables.
The software can involve balancing color, dealing with film "profiles" and calculating required input and output resolutions. Even Mac users, who may get around many of the hardware difficulties, will have to learn a new science when it comes to operating the scanning software.
If these software and hardware challenges make you feel a little uncomfortable, you are not alone. Everyone goes through a bit of trauma after they unwrap their scanner and try their first few scans.
Here are a few tips to help keep things as easy as possible:
The first thing you will want to do is to sharpen up your scan. I have never seen a scan look perfectly crisp and clear right out of the scanner. So let's now discuss what it means to use a digital sharpening filters.
- Use a film scanner if you have film and if you want to make big, beautiful prints.
- Scan negatives or slides if you can, prints if that is all you have.
- Use an air blower to remove dust and hair before you scan. This is much easier than removing the defects digitally. I use compressed air in a can called Dust Off.
- Be sure to select only the image area when you scan; first do a Preview before you scan and then crop off the black border before actually scanning the image. The scanning software will do a much better job getting accurate colors and pleasing exposure if you leave out these borders.
- Learn the maximum optical resolution of your scanner. Totally ignore the manufacturer when they mention interpolated resolution.
- Look at the estimated file size, if your scanner shows it. Shoot for a scan size of less than 1-2 MB if you are uploading the image or emailing it. Shoot for 18MB if you want to print an 8" x 10" photo and your scanner features the required optical resolution to achieve this size without interpolation.
- If possible, set it up so you scan your image directly into Photoshop (or your particular program). Try to do most of your image editing and correction in this main program instead of in the scanning software. This way, you only have one program to master, not two. Don't bother with the software that comes with the scanner, except to do the very basics - i.e. setting up the scan area and resolution.
- After scanning, immediately save your file. Then get to work cleaning it up.
I will discuss sharpening in Photoshop 6 terms and I will be happy to translate as necessary.
Not to be confused with camera filters - the kind you place in front of your lens - software filters are simply functions that are designed to create certain effects in your images.
I use the Unsharp Mark filter almost exclusively because I find it to be the most effective and easiest way to make my images crisp and clear after scanning. I also use it on images I capture with my digital camera, whenever they need a "little something extra" in order to really pop.
Why, you might wonder, did the software technicians decide to call it "Unsharp Mask" - rather than the much simpler "Sharpen"?
It is called Unsharp Mask because you are literally masking out the unsharpness. By changing the values of certain tiny areas of your image, this filter makes it look like things are getting sharper.
The bottom line is that it doesn't matter what they call it - the darn thing works wonders. So learn to use it, if you have not already.
How To Make The Magic Happen
I am going to show you step by step what I do with Photoshop 6. For those of you with other versions of software, we will have to do our best translating on an individual basis, via email or the Q&A forum.
Unsharp Mark - Step 1
Finding the Filter Menu
The first thing you want to do is locate the Filter Menu.
Next, find the Sharpen filters and select the Unsharp Mask option.
Unsharp Mark - Step 2
Finding the Unsharp Mark option in the Filter Menu.
This will open the Unsharp Mask control panel. In it, I prefer to select very small degrees of sharpening.
Unsharp Mark - Step 3
The Unsharp Mark control panel.
I recommend keeping the amount below 50%, the radius below 1.4, and the threshold at 0.
As you will notice in most of the examples in this lesson, this creates a very subtle sharpening effect. Your goal is to help the image pop just a little more without it being obvious that you used a sharpening filter.
In the examples above, this slight use of the Unsharp Mask has improved things but I still want it to be a bit more crisp. So let's take a look at the same image with the Unsharp Mask applied once more as well as one version of the image where the filter has been applied far too much.
Double Unsharp Masked
Too Unsharp Masked
My favorite is the third example, with the Unsharp Mask filter applied a second time.
(You might also notice that I removed the vapor clouds from these third and fourth examples, using Photoshop's Rubber Stamp tool - but more on that at Week 12...)
Let's sum up:
- Apply the Unsharp Mask in small degrees.
- Keep within an amount of 50% and radius of 1.4.
- Use your "Undo" and "Redo" functions (or the History palette) to flip back and forth between your before and after versions - so you can see the effect.
Even The Unsharp Mask Has Its Limits
As many times as I have tried, I cannot bring back photos from the dead, even with the amazing Unsharp Mask filter.
If your photo was shot out of focus, odds are that the Unsharp Mask filter will not be able to fix the blurriness. This wonderful filter is really best used to correct the inevitable softness that occurs when scanning an image.
Likewise, it will not be able to help with JPEG compression (the problem we discussed in the previous lesson) or with noise problems. These problems are best handled with prevention rather than after-the-fact software tricks.
Other Software That Can Help You - Big Time
There are a few awesome developments in the industry that you should be aware of:
The correcting software - most notably Digital ICE but also including VueScan, Silverfast, and FARE - are add-ons that allow you, at the touch of a button, to make sweeping corrections to your images. Digital ICE does a marvelous job removing dust, scratches, and other imperfections. Others feature color correction and other helpful functions. They work incredibly well and are super quick and easy to operate. If you are still removing dust by clicking around with the Rubber Stamp tool, or wasting hours trying to get the right colors, you have got to check into these options - they will save you a ton of time. My favorite is a Digital ICE (which generally comes with Nikon scanners). VueScan sells for about $40 ( http://www.hamrick.com ) and Silverfast ranges in cost depending upon what kind of scanner you have ( http://www.silverfast.com ).
- Digital ICE and other correcting software.
- Genuine Fractals enlarging software.
- Fred Miranda's SI Interpolation (my favorite).
The second, Genuine Fractals, is a software add-on that allows you to GREATLY increase your file size without a noticeable reduction in quality. Genuine Fractals overcomes the limitations we discussed above about resolution and sets your image free. If you only have a tiny scan or a small file from your $200 digital point and shoot, you might still be able to make a large print of your image, with the help of this software. Cost is about $160 ( http://altamira-group.com) .
To take advantage of Fred Miranda's Stair Interpolation Photoshop Actions, you need a full-version of Photoshop (not Photoshop Elements). Visit FredMiranda.com for more info.
Next week, we will take a look at the two major roads you can choose - simply fixing images or making totally new creations.
Assignment: Flower Power or People Power
As we learn these new digital techniques, we still need to continue to capture images - so we have material to scan and/or sharpen. This week's photographic assignment will involve getting some unique flower shots or interesting people photos - and then sharpening them in your software, as necessary.
Tulips from Below
Shot at the Skagit County Tulip Festival near Mt. Vernon, WA.
© Jim Miotke, 2003
All Rights Reserved
If the season in your part of the world permits, go out shooting flowers. If flowers are not blooming, you can either buy a bouquet from the store or do the optional people photos assignment.
If you decide to shoot flowers, here are the steps:
- Find out, if you have not already, how close your camera lens allows you to get to your subject before it loses the ability to focus clearly.
- Once you know how close you can get, go look for the perfect flowers. Once you find them, take a few pictures at various angles while standing above them.
- Get as low as you can to the ground. Crouch down or, better yet, lie down and look up at your subject, as much as the situation permits. Move around and look through your viewfinder from various positions. Watch how each change affects the look of your flowers and whatever is in the background. Compose your picture so that any objects in the background do not interfere or distract. Try to give your subject the supportive, even-toned background it deserves. Each time you find an interesting composition, take a picture.
- Select the one to three photos which best show off your subject. Which make it look most impressive? Which pop off the page? You will find that the photos shot from the lowest, wackiest angles will often be the most unique and interesting.
You can add an element of interest to your flower photos by lightly misting your subject with water before you shoot. If there isn't enough natural rain, mist, or dew to achieve this effect, you can use a small spray bottle for this purpose. If you sense something is missing, add a few water droplets to boost up the interest levels.
Optionally, take this week as an opportunity to photograph friends and family in all their uniqueness and character. Holidays can be a great time for practicing group portraits. Remember to take as many pictures as there are people in your group (or at least 4 or 5 exposures).
If you shoot portraits of individuals or couples, remember to keep the Rule of Thirds in mind and compose your scene in a balanced, interesting way. Whether you shoot individuals or large groups, use a small f number to isolate the focus on your subject - as long as your camera allows you to control aperture.
Then once you have your one to three favorite flower or people photos, go through the steps described in this lesson to sharpen your photo. Do not go overboard. Just give it that extra punch of crispness - without making it look unrealistic or unnatural.
As always, be sure to tell me in detail what you did to achieve the effect. Write this in the Description field as you upload the photo.
Upload your Before and After - your one best photo and the sharpened version of it - by Sunday evening.
Have a great week!
Have questions? Use our online Q&A forum or email me for answers.