AMEEL Digitization Manual: Part 5, Phase Two Processing in Photoshop 1

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1 AMEEL Digitization Manual: Part 5, Phase Two Processing in Photoshop 1 Phase Two Processing: Photoshop The Phase One processing in BCS-2 produces a series of page images tightly cropped to include only the contents of each page of the volume scanned. You ll now use a Photoshop macro to restore white margins to each image while ensuring that each has a uniform appearance and identical dimensions. You ll also process any grayscale and color images so that they are ready to replace their bitonal counterparts after OCR is complete. Photoshop Background First, it s important to take care with the processing work done in Photoshop. Any manipulation of the image that involves increasing its color depth by converting from Bitmap to Grayscale mode for instance, applying a custom rotation will degrade the image and make the text appear blurry to the user s eye. Second, when opening TIFFs in Photoshop, you will want to toggle off Pixel Aspect Ratio Correction, which will be on by default. Either select View Pixel Aspect Ratio Correction or assign a keyboard shortcut (Ctrl-Shift-R) using the Edit Keyboard Shortcuts dialog. (When on, Pixel Aspect Ratio Correction will make the image appear about half as wide as it should be.) Finally, note that you ll use several custom macros (called actions in Photoshop) to process the page images in Photoshop. Access these actions by opening the Actions palette (Alt-F9). If the folder Ameel Processing Actions is not loaded, click on the round button at the top right hand corner of the palette, select Load Actions, The automated actions included in this folder: Save-Close (F2) Resize Canvas (F3) Canvas Size Batch (F4). Initiates a batch process of the Resize Canvas option, opening the Batch dialogue. Crop-Canvas (F5). Crops the image to the current selection, then transforms canvas size to the pre-specified dimensions. Determining and Setting Canvas Size for Batch Processing First, determine the dimensions of the volume you re processing. In ACDSee, sort the page images by Image Dimensions in descending order; doing so will put the largest pages near the top of the list. Typically, these pages will be the covers. They may also include other pages upon which content extends to, or close to, the edges of the page. Identify the largest page and note its dimensions.

2 AMEEL Digitization Manual: Part 5, Phase Two Processing in Photoshop 2 In order to set the canvas size for the Resize Canvas action, you ll need to have a TIFF file open. Open a sample page from the middle of the current volume you are processing, then double click on the Canvas Size step within the Resize Canvas action. The Canvas Size dialog will open. Enter the desired width and height (in pixels), and ensure both horizontal and vertical centering are selected (see example at right). Click OK, which will resize the canvas of the current image. Then Save and Close. Running the Batch Canvas Size Transformation Press F4 to begin the Canvas Size Batch action. (First, make sure the dialog toggle the gray box with an ellipsis ( ) in it is switched on.) The Batch dialog will open. Ensure that the proper action is selected ( Ameel Processing Actions and Resize Canvas) and that the Source is set to Folder. Click Choose, then navigate to the appropriate PTIFF folder. Under Destination, choose Save and Close. Click OK, and Photoshop will open and transform the canvas size of each image in the selected folder. The images in the top row are the products of Phase One processing; each is cropped tightly to the page contents. In the bottom row, they have been centered on standardized canvases. Note: If the volume includes foldouts or any other unusually-sized pages, you must temporarily segregate those images in a separate folder before running the batch transformation. Return them to the PTIFF folder afterward.

3 AMEEL Digitization Manual: Part 5, Phase Two Processing in Photoshop 3 Processing Grayscale and Color Images Each page image in the Images folder will have a corresponding image in the PTIFF folder. The former will be either 8-bit grayscale or 24-bit color images, while the latter will be bitonal (black-and-white) images. You will deal with each pair of corresponding images one by one. Open the Images folder in ACDSee. Examining the first grayscale/color image and determine to which of the following categories it belongs: grayscale image; page includes both photo(s)/illustration(s) and text grayscale image; page features only photo(s)/illustration(s) and no text grayscale or color image that bleeds to page edges; e.g., cover or back cover The follow the steps listed under the appropriate heading below. Then repeat this process for each other grayscale/color image. Grayscale Image of Page with Photo(s)/Illustration(s) and Text a) Use ACDSee to decompress the corresponding bitonal image. (You ll use this as the base image for the composite, and must decompress it in order to give it the same pixel aspect ratio as its grayscale counterpart.) Right click and choose Convert File Format (or select Tools Convert File Format ). Select TIFF from the list in the Format pane and press the Format Settings button. Choose None under Compression, set the resolution to 300 x 300 dpi, and click OK. Click the Next > button. Select the Place modified images in source folder radio button and choose Replace in the Overwrite existing files dropdown. Click Next > again. In the final window, ensure that All pages is selected under Input and Normal is selected under Output. Click Start Convert to decompress the file. The bitonal image is at left. The grayscale image is at right. b) Open both the bitonal and grayscale images in Photoshop. c) Prepare the bitonal image to include grayscale content (the photograph or illustration from the grayscale file) by increasing its color depth. Select Image Mode Grayscale. Confirm that the resulting dialog box reads Size Ratio: 1, then click OK.

4 AMEEL Digitization Manual: Part 5, Phase Two Processing in Photoshop 4 d) Now, enhance the (original) grayscale image by deskewing it, if necessary. To deskew, select the Measure Tool by clicking and holding on the Eyedropper Tool in the toolbar and selecting the ruler icon from the dropdown menu. Using the Measure Tool, draw a line that traces an edge of the photograph or illustration that should be horizontal or vertical. Then click Image Rotate Canvas Arbitrary. A dialog box will appear, displaying the angle of rotation that Photoshop has auto-detected based upon the line you have drawn. Click OK. In the Curves dialogue box, the black eyedropper is located at left below the Options button, while the white eyedropper is to the right. At right, the grayscale image has been re-balanced so that blank areas of the page are white and the black/white contrast is stronger.

5 AMEEL Digitization Manual: Part 5, Phase Two Processing in Photoshop 5 e) Next, adjust the color balance of the (original) grayscale image in order to restore the contrast lost in the scanning process. Select Image Adjustments Curves... To get a baseline adjustment, click the Auto button. Next, to establish that the light gray of the blank areas of the page ought to be white, use the white eyedropper tool to set the white point for the image. Select the white eyedropper and click on a blank area of the page. (If necessary, manually adjust the white and black points on the curve.) Click OK. f) Now, you re ready to move the grayscale image that features (originally) bitonal text. Use the Rectangular Marquee Tool (or another selection tool if appropriate) to draw a tight selection around the photograph(s) or illustration(s) and press Ctrl+C to copy it. Move to the (originally) bitonal image and press Ctrl+V to paste. Use the Move Tool to move it into place atop the bitonal version of the photograph or illustration. (The grayscale selection currently exists on a separate layer. If the bitonal photograph or illustration is not completely covered by the new grayscale version, you can use the Layers Palette to select the background layer and delete the old content.) The originally-bitonal image is at left, now a composite including the grayscale version of the photograph. g) Flatten the grayscale selection into the rest of the image. Select Layer Flatten Image. h) Close the original grayscale image. There is no need to save changes, as you ll overwrite it with the new composite image. In the composite image, select File Save As, navigate to the Images folder and click Save. Click Yes to replace the all-grayscale image with the new composite. A TIFF Options dialogue box will appear. Leave all settings in their default positions, with NONE selected under Image Compression. Click OK. Grayscale Image of Page with Only Photo(s)/Illustration(s) and No Text

6 AMEEL Digitization Manual: Part 5, Phase Two Processing in Photoshop 6 This page from al-mawrid is an example of one containing only a grayscale photo/illustration. a) Open the grayscale image in Photoshop. b) Deskew the image, if necessary. To deskew, select the Measure Tool by clicking and holding on the Eyedropper Tool in the toolbar and selecting the ruler icon from the dropdown menu. Using the Measure Tool, draw a line that traces an edge of the photograph or illustration that should be horizontal or vertical. Then click Image Rotate Canvas Arbitrary. A dialog box will appear, displaying the angle of rotation that Photoshop has auto-detected based upon the line you have drawn. Click OK. c) Adjust the image s canvas size to correspond to that of the other pages in the volume. canvas size. These dimensions should still be set from the batch resize process you applied to the bitonal pages earlier. Simply press F3. d) Adjust the image s color balance in order to restore the contrast lost in the scanning process. Select Image Adjustments Curves... To get a baseline adjustment, click the Auto button. Next, to establish that the light gray of the blank areas of the page ought to be white, use the white eyedropper tool to set the white point for the image. Select the white eyedropper and click on a blank area of the page. (If necessary, manually adjust the white and black points on the curve.) Click OK. e) If necessary, to ensure that the blank areas of the page are white, use the Rectangular Marquee Tool to select around the photograph or illustration, select Select Inverse, and press Backspace to empty this blank space. f) Select File Save. Grayscale or Color Image that Bleeds to Page Edges a) Open the grayscale/color image in Photoshop. b) Deskew the image, if necessary. To deskew, select the Measure Tool by clicking and holding on the Eyedropper Tool in the toolbar and selecting the ruler icon from the dropdown menu. Using the Measure Tool, draw a line that traces an edge of the page (or a line on the page) that should be horizontal or vertical. Then

7 AMEEL Digitization Manual: Part 5, Phase Two Processing in Photoshop 7 click Image Rotate Canvas Arbitrary. A dialog box will appear, displaying the angle of rotation that Photoshop has auto-detected based upon the line you have drawn. Click OK. c) Remove any thumbs visible on the page image. Use the Rectangular Marquee Tool to select around the edge of the page, excluding the edges your thumb(s). Select Image Crop. (If the thumb(s) intrude well onto the page, as in the example below, or if it is not possible to select a rectangle that excludes them without excluding critical content, use the Clone Stamp Tool or the Eyedropper and Brush Tools to remove the thumb. Avoid this situation by using as little thumb as possible when scanning pages that bleed.) Here, the thumb intrudes too far onto the page to crop it out without also removing the cover illustration.

8 AMEEL Digitization Manual: Part 5, Phase Two Processing in Photoshop 8 d) Adjust the image s canvas size to correspond to that of the other pages in the volume. canvas size. These dimensions should still be set from the batch resize process you applied to the bitonal pages earlier. Simply press F3. (Ideally, the image s canvas size should already be quite close to that used for the other pages, although rotating and cropping out thumbs may have reduced it somewhat.) e) Select File Save. SUMMARY Determine and set the canvas size to be used for all of the volume s pages. Run the batch canvas size transformation to standardize the dimensions of each image. Process each grayscale and color image as appropriate.