There have been significant changes to the flatbed scanning process in the VRC (Last Updated February 23, 2007)! You can find the old tutorial here, but that should only be used for nostalgia. This tutorial documents the newest and best methods for flatbed scanning and descreening.
Open Photoshop (in the dock). Go to the File menu in Photoshop. Select "Silverfast (Epson)" in the "Import" submenu.
Put your source material on the bed of the scanner, lining up a square corner of the source material with a square of the scanner's bed, also making sure that at least one of the item's straight sides is lined up with that of the scanner (this isn't completely necessary, but if you don't do this, you will have to rotate the image within Photoshop later). If you're scanning a book, you can put the packages of Boise Cascade paper (or something else heavy) on top of it to weigh it down and keep it aligned properly. The top of the scanner doesn't have to be closed and can in fact be completely removed if it's getting in the way (unplug the cable in the back and just lift it up and off. Put it in a safe place (i.e. not on the radiator right behind it).
Click "Prescan" in Silverfast when you're ready. You can now see what the scanner sees. Adjust the alignment of the item on the bed if you want and prescan again.
Silverfast works with "Frames" (the box with blinking little lines around in the prescan window). Move and resize this box around your source image as you would with the Crop tool in Photoshop. It will make it a lot easier to tell images apart later in Photoshop if you name each frame the accession number of the image you're scanning (i.e. "706554").
The "Rotate" tool is useful for getting proper perspective on your image (and not having to rotate in Photoshop later). It rotates 90 degrees clockwise with a click, 90 degrees counterclockwise with a shift-click.
The "Zoom" tool can come in handy here. Ballpark the frame of your image, and then click the Zoom button to get a better look. You can then fine tune your frame.
For VRC purposes, scanned images need to be sized to at least 4000 pixels along their longest edge. The units should already be in pixels, but if they aren't, just click where it says "pixels" in the example image and it will cycle through different types of units. A ballpark file size for color scans is between 35MB and 45MB, greyscale scans will be smaller in file size.
The "Image-Automatic" button automatically adjusts highlights, shadows, and midtones in your image. It works very well and you should use it, but you don't have to (for example, if the image in real life looks closer to the uncorrected prescan on screen). For greyscale images, you want the little symbol to be grey. For colors, you want colors. If you see one and want the other, hold the shift key and click the button. Both symbols are shown in the example.
SilverFast likes to default sometimes to "Auto Sharpen" in the "Filter" menu, and sometimes it could be on another setting if the person working at the scanning station before you was up to something funny. Make sure that you choose the "None" option in the "Filter" menu. (Also, "Descreening" might seem like a good idea here, but we're going to descreen in less time and with better results in Photoshop later.)
You're ready! Click "Scan".
A dialogue box will pop up telling you the status of your scan. Because we're not descreening using SilverFast, the scanning process is almost instantaneous. No more surfing the internet while the scanner is chugging away. You won't have time to pull the book off of the scanner while SilverFast is working.
Now, to make this whole workflow more efficient, you should scan a bunch of images to process in Photoshop later (10 is a good number). Go back to Step 2 (SilverFast will reopen automatically) and loop through until you've got several images open in Photoshop, then go on to Step 12.
You've now got several images open in Photoshop, but you're going to work on each individually. Rotate and crop the image as you otherwise would. Don't Auto Level or Auto Color, as Silverfast has already done color correction and those will just mess the colors up.
There are two possible parts of the Descreening process, blurring and changing the image size. We are going to use the "Gaussian Blur" Photoshop filter first. Choose "Gaussian Blur" from the "Blur" submenu of the "Filters" menu. Using the live preview, set a Gaussian Blur that provides a good balance between image sharpness and moire. For my example image, I will use a blur of radius 0.3 pixels. You should never be blurring over a radius of 1.0 pixels. Also note that the moire pattern may show up more strongly on parts of your image with a solid color. Remember what the viewer wants to see! The digital image should look as much like the book image as possible. Remember, the digital image is the surrogate for a work of art. For example, don't blur details on the key part of the image in order to descreen the background. If you have an image that is about 4000 pixels on the long side and you have applied a Gaussian Blur of 1.0 and the image still has a visible screen, you have to change the size of the image. Our priority in the Descreening process is to produce images that are useful in the classroom, not to produce images that are 4000 pixels long. Go to the "Image Size" option in the "Image" menu. Adjust the size of the image in pixels down, and click "OK". Image Size does not have a live preview, so you will have to use guess and check to see what looks best for each image. The smallest size image that we can use is 1500 pixels on the long side (the size of the JPEGs online). After sizing the image down, you can apply Gaussian Blur again, but remember that we are trying to produce usable images. If the image still has a screen at 1500 pixels and you have applied a lot of blur, ask Megan or Gretchen what to do.
Save your image using the accession number written on the order sheet. Type the accession number exactly as it appears on the paper. Save your image into the appropriate folder: Macintosh HD:Scanning:Descreened TIFFs. You can now move on to descreening your next image, or if you're out of images to adjust and descreen, scan some more!
Last Updated: >February 23, 2007 by 
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