Scanning Tutorial
Untitled Document
Tips for creating better scans
Created by: bluesnow April 23, 2010 modified Sept 16, 2011
I've written this for use with Photoshop CS4 because that's what I use. You can adapt it to other versions/programs as they will have the same or similar tools.
(if you use the metric system sorry, but you'll figure it out. 1â€=25.4mm)
Many scanners cut off the edge of a cover placed tight along the edge of the scanner bed. To quickly and easily align the cover keep a 1/4†strip of card stock placed along the edge of the bed and use this edge to align the cover. Be sure the 2 sides of the card stock are parallel, IE: don't use a pair of scissors to cut it out!
After removing a cover from the case, there's a couple of pretty good creases in it. I have a wooden ruler with a round edge that I pull the cover backwards over to smooth out the spine. I also had a piece of 1/4†thick plate glass cut at a glass shop to 10†X 7â€. I place this on top of the cover before closing the scanner lid. The hard smooth surface of the glass does a good job of flattening the cover. You need to take extra care with this as the edge of the glass can scratch the scanner bed if it touches it. You should have the glass shop grind the edges smooth. I pile a couple of boxes of heavy photo paper on the lid to press things down.
Before scanning anything, I take a couple of lint free eyeglass wipes, spray them with a small amount of eyeglass cleaner and wipe the scanner glass, then dry it with a couple of dry wipes. Never spray the glass directly as some spray could seep between the glass and the frame of the scanner. Don't use Windex or any other strong glass cleaners, just eyeglass or camera lens cleaner. I also use a can of compressed air to gently blow off the glass and the cover just before I place it on the scanner bed.
I don't want to get into suggesting scanner settings. Every scanner is different, as is every cover or label. A couple of “givens†though: scan at 600 dpi and use the Descreening [/b]function if you have it. My own scanner has several settings for Descreening[/b]. I have experimented and compared each of them and settled on the one I use. My scanner also has an Unsharp Mask [/b]function which I've set to medium, again based on experiments combining it with theDescreening [/b]function. I would not allow the scanner software to perform any colour corrections, levels corrections or any other wild functions. I want to control all these myself and see exactly what changes as I do it.
I use Photoshop CS4, 64 bit. There is no 64 bit twain driver so I need to scan and save the picture in a file first. (Anyone using the 32 bit version can scan directly from Photoshop saving this step). I save the file in TIF format so there is no compression, don't start out with a compressed scan such as a JPG. Every time you re-save a JPG it gets compressed further and further. I use the PSD (uncompressed) format in Photoshop, and I'll convert my final PSD into a JPG for uploading or creating previews as my very last step. My original scan remains in tact as a TIF in case I need to start over (that happens).
Once scanned, I check that no edges got cut off by the scanner, then straighten it. No matter how well placed the cover was, it should be straightened. Several of the tips I will present rely on a straight copy to work properly. Photoshop's Ruler [/b]tool [/b]is a good way to do this scientifically.
Select the Ruler [/b]tool, then draw a line along some part of the cover that can serve as a reference for straightness. I chose the edge of the box on the back in this example. You can choose lines or the bottom edge of the title or any part of the cover that “should†be straight. I don't recommend the spine though because any curvature or crease which didn't get flattened will throw the measurement off. I also never use the outside edge of the cover.
Here I'm showing the top end of the line (the little cross hair). It's hard to see in this picture because it is very fine. After drawing the line on a full screen view, you can use the Magnifier [/b]tool to zoom in to the right area then select theRuler [/b]tool again to see it up close. You can only see the line when the Ruler [/b]tool is selected. You can drag the start/end points of the line with the mouse.
Align the beginning of the line with the reference, then scroll to the end of the line and align it similarly. Once you're satisfied that the drawn line is parallel to the reference, go Image/Rotation/ Arbitrary. [/b]You'll see a pop up window with a rotation angle. My example shows 0.050 CW which would make it vertical. My cover needs to be rotated 900 CCW to be straight so I enter
89.95 and set it to CCW then click OK. The image will be rotated so the back of the cover is straight.
Having used a reference on the back, the back of the cover is now straight. On this cover there is a sharply defined border between the back and the spine. This makes creating the back easy. Select the Rectangular Marquee [/b]tool.
Draw a selection around the back of the cover. Keep the selection just inside the edges if you can but don't worry if you can't, the Clone [/b]tool can work wonders. The rounded corners for example will be filled in later.
Avoid picking up the edge of the spine as it will be treated separately and may not be as straight as the back. Be sure your selection looks centred then select Copy [/b]under the Edit [/b]menu to place the selection on the clipboard.
Under the File [/b]menu select New[/b]. Be sure the Preset [/b]says Clipboard[/b]. The new document size will be the same size as the selected area by default. Choose OK [/b]to create the document, then select Paste [/b]under the Edit [/b]menu. The back of the cover will now be a new document.
Once the back of the cover is in a new document, it needs to be re-sized. Select Image [/b]then Image Size, [/b]uncheck Constrain Proportions [/b]and check Resample Image [/b]using Nearest Neighbour [/b]for the interpolation method. Enter 300 for the Resolution [/b]first, then 1535 pixels for Width [/b]and 2175 pixels for Height[/b]. I always reduce the resolution to 300 dpi at this point as many of the touch up filters and tools I use later behave differently at 600 dpi. The Despeckle[/b]filter is one and the Blur [/b]tool is another, both are more effective at 300 dpi. You will learn over time how to “feel†each tool better if you work with the same resolution each time, so be consistent. Save this document as 'your movie'[/i]back.psd
The background on the front of this cover wraps around onto the spine, you can see this in step 6 above. This means the spine and front need to be treated together or else they won't match up. Use a rectangular marquee to select the front plus the spine together. After placing the marquee, zoom in close and adjust the position of the selection, using the arrow
keys, so the back edge of the marquee is right on the back edge of the spine. Scroll up and down the spine to check the straightness of the spine against the marquee. If they don't match, you may want to straighten the cover again using a reference on the front or spine, then re- select.
It is ideal when the spine has a different background than the front and the back. You can then separate the cover into 3 parts; back, front and spine. Selecting the spine is the only fussy part, you need to stay inside the edges to reduce cleanup but ensure the spine title and any pics or logos etc. are centred within the selection. Size each to their finished sizes of 1535 X 2175, 1535 X 2175 and 170 X 2175 respectively. With careful selections you won't need to clean up much along the edges. I like to adjust the 3 parts for quality separately so I can easily use different settings on each when needed. Usually the front has a large picture and large text while the back has small pictures and a lot of finer text. They usually warrant different treatments.
You will assemble the 3 parts when they're finished into the final cover on a new blank document which is 3240 X 2175 and sized to “Fit Screenâ€. For each of the 3 documents, go to Select/All [/b]then go to Edit/Copy Merged [/b]and paste each into the new document. Copy the spine last and it will be centred.
Edit: Since writing this I have changed my method slightly. I now size the back, front and spine to 1539 X 2177, 1539 X 2177 and 172 X 2177 respectively. I then use Image/Canvas Size [/b]to crop them to 1537 X 2175, 1537 X 2175 and 170 X 2175 respectively. This leaves a keener edge after interpolation and the overlap eliminates a 1 pixel gap that often showed up. Remember though to paste the spine last so it's on top.
Now for the tricky part. How to clean up a scan depends on what you're starting with. Most scanners produce a picture with a lot of half tone dots. These are the hardest things to get rid of without ruining something else. Each scanner produces different results and therefore the path to follow cannot be fixed. I'm going to present a few sample steps here to demonstrate how a scan “might†be cleaned up, but your case “might†be different. Some experimentation is in order to learn how the tools and filters behave before you can settle on a typical course to follow on your own scans. It's a good practise to duplicate the original layer and work on the duplicate. You can then always delete the upper layers and start fresh if needed.
To demonstrate, I have scanned a small section of my cover so the detail can be seen at this size, then performed a few steps to show what can be done. I have not created the perfect scan, only demonstrated the use of some filters and tools. Some thought, finesse and experimentation could produce better results.
Note the white dots in the darker areas.
My first step was to apply a Despeckle[/b]. Sometimes a Gaussian Blur [/b]is a better first step, followed by a Despeckle [/b]or even two. I tried it both ways but I found this time that theDespeckle [/b]was effective without the blur. Despeckle [/b]is found under Filter/Noise[/b]. Most of the dots disappeared but a pattern still exists, most obvious in the dark blue area. There are no variable settings for the Despeckle [/b]filter and I find it works much better at 300 DPI than at 600 DPI. Sometimes two despeckles in a row works well but watch out for what happens to the fine text.
The second step was the Gaussian Blur [/b]with a Radius [/b]of 0.6. I keep Gaussian Blur [/b]very low as it really can destroy fine text and logos. The range though can be from 0.4 to 1.6 depending on the scanner and the detail. Sometimes you need to select certain areas or parts to exclude or apply different settings to. If a Despeckle [/b]is effective at first then the blur can usually be set to a lower value.
Don't expect this step to eliminate all of the patterns. I almost always use a small Guassian Blur [/b]then follow it with a Smart Blur [/b]as in the next step here. Smart Blur [/b]is much kinder to the fine text, but not as effective at smoothing colour. If the text is fine enough though, it can treat it like any other part and smear it. Testing how the two blurs work together with a particular scan or cover is required.
The third step was a Smart Blur[/b], Radius [/b]1, Threshold [/b]10, Quality [/b]High. The difference here isn't too obvious without zooming, but a lot of smoothness was created in the darker areas especially in the blue. Too much Smart Blur [/b]can make areas like faces blotchy and look like there's too few colours. I pretty well always use a radius of 1 and just vary the threshold.
With each step, carefully examine the fine text and logos. You may want to undo, and try a different approach, or be selective and use different filters for different parts using masks.
Step four was a Levels [/b]adjustment. I set the levels for R, G and B separately. This brightened up the colour and improved the contrast. I'll move the black and white sliders to the edges of the curves. After setting all 3 I have a look at the picture to decide if I want to move the grey slider to brighten or darken things.
Next I used a Selective Colour [/b]adjustment. I increased the Black component in the Blacks and decreased it in the Whites. This removed that mottled looking grey in the black background around Alec Baldwin and brightened up the white text. There will be some loss of detail in the dark areas, take care not to over do it.
My next step was to sharpen the image using Unsharp Mask[/b], Amount [/b]100%, Radius [/b]1 and Threshold [/b]1. The text begins to jump out now but some pixelation (if I can call it that) shows up around Alec Baldwin's face and tie. It also improved the look of the red border around his picture. I usually go by the text to set the sharpening, using an Amount [/b]ranging from 60 to 100% and a Radius [/b]between 0.6 and 1.5. My Threshold [/b]settings vary between 1 and 4. I try to enhance the text without ruining the pictures. Again, sometimes being selective and using a mask to sharpen different areas separately works best.
Finally I used the Blur [/b]tool to smooth Alec out a bit. The Blur [/b]tool does not seem to be effective at all at 600DPI. Keep in mind that this picture shown here is over 250% actual size. In viewing the actual sized cover it really looks pretty good.Â
Actual size
After my final sharpening, I pull out the Clone [/b]tool. The Clone [/b]tool is the scanner's best friend. I use it last because the filters tend to eliminate most of the dust particles and defects for you. Sharpening however can bring out some you never saw. I have a pretty big monitor but I still zoom to 200%. Start in a top corner for example and scroll down to the bottom searching for defects that should be removed. When I reach the bottom, I'll pull over a new guide to the edge of the area I've just finished, then move over and start scrolling up. As I finish each “column†I move the guide along. This always marks the sections that have been done so I don't miss any when I get interrupted.
There are tutorials on cloning so I don't need to go into the “howâ€. My best advice is to keep it soft. One point I could mention is that it can be hard to remove defects in a row of fine text if you try to get in between letters. If there's a defect between the 't' and the 'h' in a word, just find a nearby 't' or 'h' or 'n' or any part of any letter that matches and align the Clone [/b]tool reference there. The Clone [/b]tool in CS4 provides a preview so you can clone the bottom half of a letter quite accurately while at the same time eliminating the defect.
Occasionally a project comes along where selecting using the proper size ratio just doesn't work well. Here's an example of a cover I scanned where the case wasn't even close to our standard DVD case sizes. The back just wasn't the right shape. I had no choice but to make the back selection much wider than wanted. Re-sizing then created problems with the pictures and logos. Text can pretty much be squashed or stretched (to a point) without making it look odd as there are lots of fonts out there, it'll just look like a slightly different one. Without having the original to compare to, you'd never notice it. The logos along the bottom were easily replaced or repaired but I had to protect the pictures so the people didn't look out of shape.
Here's one place where straightness helps. After creating the back in a new document, but before re-sizing, I selected the picture of the kids just on the inside of the red border. I cut them out to place them on the clipboard, then re-sized the back to 3070 X 4350 @ 600 DPI.
I then pasted the picture back and used the transform controls in the Move [/b]tool to stretch it linearly [/u]in both directions to maintain the same proportion, until it just filled the void. I then moved this layer underneath so the picture showed through the void. This enabled me to reshape the back of the cover without reshaping the kids. The point is that you can break up a cover into as many parts as needed, finish each part, then reassemble it.
Here's a cool way to perfect scanned bar codes. The method requires the image to be flat so if you're not ready for that, use Copy Merged [/b]under the Edit [/b]menu and paste it into a new document. Here's a bar code as canned.
Make a Levels [/b]adjustment using the black and white eyedroppers on a bar and on a grey portion of the background respectively. Then use Selective Colour [/b]and increase the black component in the Blacks[/b], and decrease the black component in the Whites[/b]. Then flatten the image.
Set your foreground to white and background to black. Use the Rectangular Marquee [/b]tool to draw a rectangle around a narrow bar. The bar will likely have a grey edge so guess at what the width the bar really should be. With the Marquee Tool [/b]still selected, hit the delete key. The bar should turn black and sharp. Don't worry about the grey edge yet. Use the left/right arrow keys to scroll the selection to the next bar. Hit delete again. Continue in this manner for all the bars that are the same height as your existing selection. If the bar is wider than the selection, like the 3rd and 4th ones in this example, just start deleting at the first edge then move over and delete some more.
Without losing your selection, switch the foreground and background colours and begin to scroll the selection backwards again, stopping and deleting between the edges the bars. This gets rid of the grey parts. You can switch the foreground and background colours back and forth as needed to correct the bar widths. Change the selection to a shorter bar and repeat the process with them.
You can set the lengths of the bars to all be equal by setting the background colour to white and selecting a marquee across the ends of the bars, then hitting delete. Do this for the bottoms of each group of bars as well.
Once you get the hang of it, you can use 2 fingers, one on the arrow keys and one on the delete key to create the perfect bar code in just minutes. Replacing the text would then be the final step if you want the ultimate. It looks great in your scan but don't expect any bar code scanners to read it!
The Dodge Tool [/b]can be used to brighten light coloured text.
Before After - Range:Highlights, Exposure:15%, 2 passes
The Burn Tool [/b]can darken dark coloured text.
Before After - Range:Shadows, Exposure:20%, 3 passes
The Blur Tool [/b]can be used to smooth some “blocky†pixels and oversharpened edges, and the Clone Tool [/b]set to “Darker Color†and aligned on the background can quickly remove the white halo around dark text after a sharpening.
You can use the Paint Bucket [/b]to easily smooth out sections of a scan where the original had a solid colour such as the background on the spine or the widescreen banner across the top, where there's a distinct edge against other areas. No masking or selecting is needed. Use the colour sampler at maybe a 5 X 5 average and sample the area. Then select the Paint Bucket [/b]tool and set the Mode [/b]to Normal, Opacity [/b]to 50%, Tolerance [/b]to 10% and check Anti- alias [/b]and Contiguous[/b]. Click on the area to be smoothed. Each successive click will smooth it further. Notice how the background of this spine smooths out from left to right. The Tolerance [/b]setting of 10% keeps the Paint Bucket [/b]from colouring the blue shadow under the title. Enclosed areas such as between the 'L' and 'A' in the word PLANET need to be handled separately.
Selective Colour is one of my favourite tools. Here's a perfect example of how it can be used to enhance the colours as well as eliminate some defects in a scan. I've already done some work on this scan; Gaussian Blur, twoDespeckles, Smart Blur and a Levels adjustment. At this point I want to bring out the colours. It is probably only barely noticeable at this scale but there is a lot of grey in the black areas, especially in the section below the astronaut's arms. Their arms themselves look a little lifeless.
I created a Selective Color Adjustment [/b]layer (no masks) and made the following adjustments . . .
Blues (to brighten earth) Whites (to brighten text) Blacks (to blacken space) Neutrals
Cyan +10% Black -20% Black +20% Black -10%
Magenta -10% Magenta +5%
Black -10%
This brought out the colours. All I had to do after this was to increase the contrast, brighten it a bit and sharpen. Here's the final product ready for the Clone Brush [/b]to complete it's job.
The real beauty of Selective Colour is that it can turn . . .
this into this
Cartoon covers tend to use more solid colours rather than smooth gradients like in photographs. The Smart Blur [/b]filter can be applied more heavily to smooth out colours and reduce noise.
Before Smart Blur[/b]
After Smart Blur [/b]add some Unsharp Mask [/b]and it's done!
A Word About Interpolation
When an image is re-sampled such as rotated or re-sized, Photoshop must calculate new colours for all the pixels (the pixels don't move, they just get assigned new colour values). You can select which of 5 different algorithms Photoshop should use.
Nearest Neighbour: A fast but low precision method that replicates the pixels in an image. This method is for use with illustrations containing edges that are not anti-aliased, to preserve hard edges and produce a smaller file. However, this method can produce jagged effects, which become apparent when you distort or scale an image or perform multiple manipulations on a selection.
Bilinear: A method that adds pixels by averaging the colour values of surrounding pixels. It produces medium-quality results.
Bicubic: A slower but more precise method based on an examination of the values of surrounding pixels. Using more complex calculations, Bicubic produces smoother tonal gradations than Nearest Neighbour or Bilinear.
Bicubic Smoother: A good method for enlarging images based on Bicubic interpolation but designed to produce smoother results.
Bicubic Sharper: A good method for reducing the size of an image based on Bicubic interpolation with enhanced sharpening. This method maintains the detail in a re-sampled image, but can over sharpen an image.
I have found that the Bicubic [/b]algorithms leave you with a 1 pixel semi-transparent border all around an image when re-sizing. They don't do too bad a job of rotating, but my preference is for Bicubic Smoother [/b]for rotating.
I would choose Bilinear [/b]or Nearest Neighbour [/b]for re-sizing a cover to avoid the problems around the outside edges. Bilinear [/b]still leaves a semi-transparent edge sometimes. I would use one of the Bicubic [/b]functions to re-size an image that I was pasting into a cover such as a screen shot or figure cut from another image as the semi-transparent border is like a feather, it will blend into the background.
You can specify a default interpolation method to use whenever Photoshop re-samples an image under Edit/Preferences/General[/b]. I've set mine to Bicubic Smoother [/b]because you can't specify the interpolation algorithm when rotating, it uses the default. Because of this I have to remember to set the interpolation method every time I re-size, depending on what I'm resizing and what it will be used for. CS2 never seemed to have this problem. You should experiment with the default setting to see how it affects rotating and re-sizing. Do this with an image, such as a duplicate, that you can afford to ruin!
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