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SCANNING IMAGES -- USING THE HP 3970 SCANNERS IN ROOM 242
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IMPORTANT NOTES ON IMAGE RESOLUTION
If you would like to scan drawings and photographs for full-screen video, or if you create images directly in the computer, the image resolution for such files should be at least 720 x 540 "square" pixels. Using the same 4:3 aspect ratio, another useful resolution for animation is 1440 x 1080 pixels. Although the file size is larger, the format works well for digitally inking and painting images.
Typically, you will eventually use video editing programs like Adobe Premiere or After Effects, or Apple's Final Cut Pro, to export movie files to mini-DV cassette, or to use image sequences in the Perception Video Recorder and output material to VHS videotape. When you do so, as a final production step, the software will render the material at a resolution of 720 x 480 "non-square" pixels.
When you use a Perception Video Recorder and video camera to capture a series of animation drawings, the PVR software will record images at 720 x 480 pixels. When you look at the images directly on a "non-square" NTSC video monitor, the images should look fine, where circles appear to be circles and squares look like squares. However, if you were to open the images with Photoshop or Premiere (software that is viewed on a "square-pixel" monitor), the circles will undoubtedly appear to be oval shaped and the squares will look rather rectangular. This shift is due to the difference between square and non-square pixels, viewed on the wrong kind of monitor.
USING THE HEWLETT-PACKARD 3970 SCANNER
The two computers with the Hewlett-Packard scanning software in room 267 have both "HP Director" and "HP Photo & Imaging" installed on the machines. Although you can scan from both programs, for animation purposes, you should only use the HP Director to scan images and image sequences. You can then use HP Photo & Imaging to see thumbnails of the scans, change the file names, and organize the images. Unfortunately, HP Photo & Imaging has one or two nagging problems with its particular scanning preferences, options that will undoubtedly frustrate you when you scan image sequences. Therefore, you should use the HP Director to scan your drawings.
Output destination When you use the HP scanner to capture a large number of animation drawings, it is important to realize that you should not save the files over the network to your home directory. In doing so, it will not only take longer to save the material because of the time required to transfer the data over the network, you will risk corrupting the files in the process. Instead, you should establish a folder in the workstation's temporary workspace (i.e., Save Here / Your name / image scans) and scan the images to that directory. When you've completed the task, you can then transfer the folder to either your network space, burn them on a compact disk, or add them to a portable hard drive.
Scanning preferences Once you have made a folder to place scans, open the HP Director, by going to Start > Programs > Hewlett - Packard > Scanjet Scanner Series > HP Director. Following which, you must set your scanning preferences:
- Choose Settings > Scan Picture Settings > Save Settings. Select the "Save To" tab and then use the Browse Button to locate the folder in the Scratch Disk (or Save Here disk).
- For "Output Type," select "Millions of colours (24-bit image)." If you would like to scan drawings that you plan to paint digitally later, you can scan at "256 shades of grey (8-bit greyscale). However, you must then use Photoshop to change the greyscale images to RGB files.
- Regarding "Save as File Type," choose "Tiff Image" (which should be "uncompressed").
To begin scanning, you should place a standard-issue "ECI field guide" on the pegbar attached to the scanner glass. ECI field guides have been designed specifically for the HP scanner, to capture images drawn on field 9.5 on 8.5 x 11 size animation paper.
It is important to note that you will have to scan your drawing sideways or at a vertical orientation. Not to worry though, you will be able to use Photoshop to rotate the images later on.
Referring to the HP Director, remember that you must not proceed until you have selected your folder on the Scratch Disk, as a place to save the images to. After that, click on the "Scan Picture" icon to call up the scanning software (see above).
Image dimensions Once the software is open, you will notice two icons in the lower region of the HP Scanning window: "New Scan" and "Accept." If you click New Scan, the software will preview your animation field guide (or, alternatively, the artwork you intend to capture). However, it will preview the artwork at its default dimensions.
Therefore, you must change the dimensions to suit your production regime. To do so, you should look to the right-hand side of the HP Scanning Window. From there, you can change settings for either "standard-" or "high-definition" images:
Standard resoloution
First of all, go to Resolution. Click the expand arrow and change the amount to 75 dpi.
Then, go to Resize and expand its section. There, you will find several values that you can change. Referring to both the Selection Area Dimensions and Output Dimensions, you should type in:
High resoloution
In the same way that you would adapt standard resolution settings, go to Resolution. Click the expand arrow and change the amount to 150 dpi.
Then, go to Resize and expand its section. Fom there you can change both the Selection Area Dimensions and Output Dimensions, by typing in:
It is important to know that you will be scanning your drawing sideways or at a vertical orientation, which you will then use Photoshop to rotate later on.
Finally, you must then secure the resolution by clicking the “lock icon” in the Resize section. It is essential that you remember to do this, otherwise you will scan images at an incorrect resolution (which is disastrous for animation production).
Registering the scanning region Once the software previews a scan, an image of artwork and a bounding box will appear in the HP Scanning Window. When you move the computer mouse and curser towards the left-hand side of the scanning window, the curser will then turn into a move tool. Click and drag the tool to move the bounding box over your field guide or artwork. You should then carefully line up and resize the frame (by clicking on and dragging the black squares at the edges of the bounding box, to frame it over the field guide).
If you wish, you can use the image manipulation options located at the right-hand side of the HP Scanning Window to adjust levels, colour balance, etc., but you can also make adjustments later in Photoshop. There is an advantage to using Photoshop because you will be able to assign an action and change large amounts of files with the Batch Process option.
The scanning process When it comes to scanning images, you should click on the Accept Button (do not use New Scan).
After the machine has made a scan, a dialogue box will then appear, asking "Do you want to scan another image?" If you are only scanning one image, press "No." However, if you plan to capture multiple files, press "Yes." Do not use "New Scan:" doing so will throw off your registration.
Image sequences The primary reason why you should start the scanning process by previewing your field chart is to line up the scanner with the animation guide. Once you have registered the bounding box, you can then proceed with scanning the image sequence by doing the following:
- Open the scanner lid and place the first actual drawing from the sequence on the scanner bed. Press "Accept."
- After the machine has made a scan, a dialogue box will then appear, asking "Do you want to scan another image?" If you plan to capture more files, press "Yes." (Do not use "New Scan:" doing so will through off your registration.)
- You should repeat the process by opening the scanner lid and replacing the first drawing with the second in the sequence. You do not have to preview the drawing again because, when you scanned the original field guide, the process established the proper registration for the sequence.
- Press Accept, etc.
- Finally, once you have made your way through all of your drawings, complete the process by clicking No as a response to “"Do you want to scan another image?"
When using a scanner to capture animation drawings, it is often necessary to rotate the images, adjust their size, and image quality, etc.
USING PHOTOSHOP TO CHANGE FILE DIMENSIONS AND RESOLUTION
Referring to Photoshop's main menu, go to Image > Image Size. From here, you can change a file’s resolution (or dimensions at least).
For Pixel Dimensions, you should remember that, at the very least, production images for full-screen video must be at 720 x 540 pixels before they are resized to a 720 x 480 non-square pixel resolution.
It is best to keep Constrain Proportions activated, otherwise you may run the risk of either squashing or stretching a given file.
Regarding Image Resampling, select Bicubic.
TO CHANGE THE CANVAS SIZE OR ADD PIXELS TO AN IMAGE FILE
Referring to Photoshop's main menu, go to Image > Canvas size. New size: Using pixels as a unit of measurement, enter a new width and height.
For Anchor, click where you wish to place the existing document. If you choose the centre, Photoshop will distribute an equal amount of pixels around the current file. If you select the top, the software will add pixels below the documents and distribute pixels to the sides, etc.
TO ROTATE IMAGES ONCE THEY HAVE BEEN SCANNED
Go to Image > Rotate Canvas > 90 CCW (counterclockwise).
TO MAKE TONAL ADJUSTMENTS WITH THE LEVELS COMMAND
Refer to Photoshop’s main menu and then go to Image > Adjustments > Levels.
The Levels command is a good way to manipulate the tonal values of a document. As part of its function, the Levels dialogue box displays a histogram, which is a kind of bar chart that plots an image's highlight, shadows, and gamma (or mid-tones) on a scale from 0 to 255. This gauge is set along the histogram's horizontal axis. The number of pixels at each level is measured along the histogram’s vertical axis. Therefore, if there is a large amount of dark pixels in an image, the histogram will show a peak shape towards the left region of the guide.
Referring to the Levels dialogue box, there are three Input Level sliders that you are meant to manipulate, in order to adjust the black-point, white-point, and gamma (mid-tones) in an image. When you move the sliders towards the centre of the histogram, you will subsequently increase the overall contrast of the image.
When you move the black-point slider away from zero toward the right-side of the scale -- towards white -- the current levels at the black-point slider and those that are less than the black-point slider will then move to zero. As a result, as the black-level moves, the image's entire tonal range of 0 to 255 will shift as the slider is moved. Increased dark values will begin to appear in the image.
The opposite will occur as you shift the white-levels toward black. Increased highlight values will then appear in the image.
The gamma slider allows you to alter the image's mid-tone values, without changing the highlight or shadow points. As you move the slider to the left, the Levels adjustment shifts highlights together and the image will therefore appear to be lighter.
Output levels compress the tonal range of an image into fewer values than 255 steps of grey. This function is used for artists intending to print images from Photoshop. For animation purposes, the input levels should suffice.
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