This tutorial will provide a solution to the following issues with large pre-1923 scanned PDFs from Archive etc. on Kindle and other ebook readers:
1.) How do I display large PDF scans of out-of-copyright PDF documents? Books with old brown pages turn slowly on my Kindle, and the cover page (black/dark-colored cover) freezes my Kindle, requiring restart. What do I do?
I answer that,
Step 1: Search for and download 'K2pdfopt', a portable software available for Windows, Mac, and Linux. Launch it and maximize (enlarge) the window if necessary. Add the PDF file using the 'ADD FILE' button. You may use the 'ADD FOLDER' button to add a folder full of PDF files. Also, set an Output Folder where the Optimized PDF file will be saved. This can be done by clicking the 'Select' button, navigating to the desired Output folder, and clicking 'OK'.
Step 2: In K2pdfopt, near the top-right area, just above the Preview Window, you will see a drop-box with the label 'Conversion Mode'. Select 'copy', which is the second option from the top.
Step 3: Check that the 'Device' drop-down box shows 'Kindle 1-5', the first option from the top. If not, select this option. Do this irrespective of the device you use. Moreover, check that both the width and height are set to 1.00s. If not, adjust the four boxes to show '1.00', 's', '1.00', and 's'.
Step 4: Set the DPI to 300. You may do this irrespective of the DPI of your device. Alternatively, you may search for the DPI of your device on the internet, and enter that value. Not that the DPI should not be too less or too large, the ideal value being 300.
Step 5: Untick/deselect the 'Color output' option and the 'Smart line breaks' option. Check that all other options are not selected. All the options on the bottom should be kept unselected/without tickmark. 'Max columns' option should be set to 1, irrespective of the number of columns in the PDF file. So if there are two columns of text in the PDF, even then this option should be set to 1. The Document resolution factor should also be 1. The 'Pages to convert' textbox should say 'all'. Keep it like that to optimize the entire PDF. Or if you want to optimize a certain page or range of pages, select the page number or page range in the format '40' or '40-50' to optimize page 40 or pages from page 40 to 50.
Step 6: Click 'Convert all files'. Wait for the conversion to complete. This may take a few minutes, depending on the processing power of your computer. The optimized PDF will be saved in the output folder which you had previously selected. The name of the PDF will be something like [<filename>_k2opt(dot)pdf.] Transfer this newly optimized PDF to your Kindle or device through USB cable or other means. This PDF will have black text on white background, and page turns should be as smooth as regular ebooks. Thus, the heavy scanned PDF is now easily readable on your Kindle device.
2.) How do I make the PDF have white text on black background? In other words, how do I set the PDF to Night Mode or Invert Colors Mode or whatever one calls it?
I answer that,
Proceed to perform step 1 to step 5 in Question No. 1 (near the top of this article). Skip Step 6.
Instead, copy-paste the following line into the 'Additional options' box:
-colorbg <ffffff>|<000000> -colorfg <000000>|<ffffff>
Include all the symbols, letters, and numbers, from the '-' sign at the beginning to the '>' sign at the ending. Try not to type it manually, in order to avoid spelling mistakes.
The purpose of this line is to invert colors of your PDF.
(Explanation: <ffffff> represents the color white, and <000000> is black. This line will invert black and white, and since the PDF output will be grayscale according to our settings, colored PDFs will first be converted to grayscale and then inverted from black-on-white to white-on-black)
Now proceed to Step 6, by clicking 'Convert all files' and transferring the resultant optimized PDF to your device.
Now you will be able to read read PDFs with inverted color without using a certain accessibility feature included in later models of Kindle. Moreover, this change is saved to the optimized version of the PDF file, and not dependent on a device setting. This is especially useful for those desirous for an 'Invert Colors' accessibility feature on older devices that do not have it.
That's it for this tutorial. I hope it helps.
1.) How do I display large PDF scans of out-of-copyright PDF documents? Books with old brown pages turn slowly on my Kindle, and the cover page (black/dark-colored cover) freezes my Kindle, requiring restart. What do I do?
I answer that,
Step 1: Search for and download 'K2pdfopt', a portable software available for Windows, Mac, and Linux. Launch it and maximize (enlarge) the window if necessary. Add the PDF file using the 'ADD FILE' button. You may use the 'ADD FOLDER' button to add a folder full of PDF files. Also, set an Output Folder where the Optimized PDF file will be saved. This can be done by clicking the 'Select' button, navigating to the desired Output folder, and clicking 'OK'.
Step 2: In K2pdfopt, near the top-right area, just above the Preview Window, you will see a drop-box with the label 'Conversion Mode'. Select 'copy', which is the second option from the top.
Step 3: Check that the 'Device' drop-down box shows 'Kindle 1-5', the first option from the top. If not, select this option. Do this irrespective of the device you use. Moreover, check that both the width and height are set to 1.00s. If not, adjust the four boxes to show '1.00', 's', '1.00', and 's'.
Step 4: Set the DPI to 300. You may do this irrespective of the DPI of your device. Alternatively, you may search for the DPI of your device on the internet, and enter that value. Not that the DPI should not be too less or too large, the ideal value being 300.
Step 5: Untick/deselect the 'Color output' option and the 'Smart line breaks' option. Check that all other options are not selected. All the options on the bottom should be kept unselected/without tickmark. 'Max columns' option should be set to 1, irrespective of the number of columns in the PDF file. So if there are two columns of text in the PDF, even then this option should be set to 1. The Document resolution factor should also be 1. The 'Pages to convert' textbox should say 'all'. Keep it like that to optimize the entire PDF. Or if you want to optimize a certain page or range of pages, select the page number or page range in the format '40' or '40-50' to optimize page 40 or pages from page 40 to 50.
Step 6: Click 'Convert all files'. Wait for the conversion to complete. This may take a few minutes, depending on the processing power of your computer. The optimized PDF will be saved in the output folder which you had previously selected. The name of the PDF will be something like [<filename>_k2opt(dot)pdf.] Transfer this newly optimized PDF to your Kindle or device through USB cable or other means. This PDF will have black text on white background, and page turns should be as smooth as regular ebooks. Thus, the heavy scanned PDF is now easily readable on your Kindle device.
2.) How do I make the PDF have white text on black background? In other words, how do I set the PDF to Night Mode or Invert Colors Mode or whatever one calls it?
I answer that,
Proceed to perform step 1 to step 5 in Question No. 1 (near the top of this article). Skip Step 6.
Instead, copy-paste the following line into the 'Additional options' box:
-colorbg <ffffff>|<000000> -colorfg <000000>|<ffffff>
Include all the symbols, letters, and numbers, from the '-' sign at the beginning to the '>' sign at the ending. Try not to type it manually, in order to avoid spelling mistakes.
The purpose of this line is to invert colors of your PDF.
(Explanation: <ffffff> represents the color white, and <000000> is black. This line will invert black and white, and since the PDF output will be grayscale according to our settings, colored PDFs will first be converted to grayscale and then inverted from black-on-white to white-on-black)
Now proceed to Step 6, by clicking 'Convert all files' and transferring the resultant optimized PDF to your device.
Now you will be able to read read PDFs with inverted color without using a certain accessibility feature included in later models of Kindle. Moreover, this change is saved to the optimized version of the PDF file, and not dependent on a device setting. This is especially useful for those desirous for an 'Invert Colors' accessibility feature on older devices that do not have it.
That's it for this tutorial. I hope it helps.