Have you ever been given images that have been previously printed, perhaps in a catalog, and been expected to use them in your own design? Previously printed images look horrible when scanned back into the computer, but sometimes you just have to do it. There must be a way to improve them, right? Right!
Fixing scanned images is actually pretty simple. It’s not going to look as good as if you had the original digital files, but it won’t look too bad, either.
Analog to Digital
Scan the image at double the final resolution you want.
For example, if you want the final image to be 3x4 at 300 ppi and 3x4 is the original image size, scan at 600 ppi.
If the image is originally 3x4 and you need it blown up a bit to, maybe 6x8 (we’ll make the calculations easy), then you need to scan it at 1200 ppi—double the resolution to increase the dimensions, then double it again for the purposes of scanning. An image blown up that much from prior printed material probably won’t look very good and I wouldn’t advise increasing the size too much.
But It’s Crooked!
…I hear you cry. Now that the image is in the computer, of course it’s crooked. It’s too much hassle to try to get it straight on the scanner bed, we’ll just fix it in Photoshop.
Ever heard of the Measure Tool? Well we’re going to use it. It’s under the Eyedropper Tool. Click and drag the measure tool along the edge of the image.
Now, go look at the Info Palette. See in the upper right hand corner it says A: __ degrees? Remember that number.
Go to Image>Rotate>Arbitrary. No, our adjustment won’t be arbitrary at all! Plug in the number degrees and for this image I needed to rotate clockwise (CW, CCW is counter clockwise if you’re curious). Ah! Straight image! No hassle!
I Still See Spots
See the moiré pattern to the left of the original image above (the speckley pattern)? That’s bad. Let’s get rid of it. Go to Filter>Blur>Gaussian Blur. Select a pixel radius that mostly gets rid of the pattern without blurring the image too much. Don’t worry if the lines and type get a little fuzzy, we’ll fix that next.
Blurry is Bad
Now go to Filter>Sharpen>Unsharp Mask. Match the pixel radius you just used for the blur. You can adjust it a little to see if it looks better more or less sharp.
Final Step
Now we need to sample the image down to its final size. Go to Image>Image Size (or Ctrl+Alt+I in CS2+) and check the box at the bottom that says Resample Image. Change the resolution to the final size (should be half of what it was before). The dimensions (in inches, cm, etc, not pixels) should stay the same if you’ve checked the Resample box. All done! I know you can’t tell much of a change in this low-res web environment, but try it yourself. You’ll see it makes a BIG difference!
Quick Review
- Scan image at double the final resolution
- Use the measure tool to figure out the angle of the image
- Image>Rotate>Arbitrary and plug in the angle you found on the Info Palette
- Use Filter>Blur>Gaussian Blur to get rid of the moiré pattern
- Use Filter>Sharpen>Unsharp Mask to sharpen the lines and type
- Downsample to the final resolution
Oh, and for scanning photographs (not printed offset, litho, etc) use the Dust and Scratches filter to get rid of the lint and dust that shows up on them!
What about your scanning experiences? Do you have a different method?
For rotating elements I use edit > transform > rotate, rather than rotate the whole canvas. It also allows me to rotate with handles, so I can see it in real time. Perhaps that’s new to CS3?
No, it’s not new to CS3. I usually use Ctrl+T to get free trasform to rotate most objects. But the measure tool and the arbitrary rotation to fix scans makes it exactly right without guessing. It just seems easier to me. Try it sometime! Let me know what you think :)
That is an exactly perfect walkthrough of how people should be scanning print work. People should print this out and leave it by their scanners =) Nice work!
Thanks Chris! Did you print it out and put it by your scanner? ;)