Cover Scanning in the Retina Age

This page is a sequel rather than a replacement for my original guide to comic-book cover scanning. Read it here:

http://lrpctechblog.com/comic-books/cover-scanning/

As I’ve mentioned elsewhere on this site I did make the switch from ComicBase back to ComicCollector as far as my collection management software of choice. My main reasoning for the return to the CollectorZ program was the fact that they do offer a fairly amazing iOS app that works GREAT with my iPad. While transferring my scans to the new iPad I noticed that my own high rez scans (at around 1,150 pixels in height) looked pretty nice on the Retina screen even though it was scaled (multiplied to be more accurate) UP to the iPad’s portrait mode height of 2,048 pixels. So I wondered how much better/sharper it would be if the image actually MATCHED that insane 2,048 pixel goodness. So I did some test scans of some covers that were for some reason missing from my image archives. The results were spectacular. So after a little experimentation I have some new settings that give me a cover image that takes full advantage of the Retina iPad screen and hopefully future PC displays as the industry eventually plays catch-up. Here is the new recipe (most everything from the original guide still applies with a couple of key changes):

Retina Ready Scans:

1. Scan at 300 DPI with auto tone and Unsharp Mask OFF. Make sure Descreen is ON.

2. Adjustments – auto levels

3. Image Size –change Pixel Dimensions Height to 2048

4. Sharpen –Unsharp Mask -amount: 50%, Radius: 1.0, Threshold: 0

5. Save as Jpeg quality: 10, Baseline Optimized

Resulting file is between 750kb and 1.9MB (depending on color level). Average so far for me after doing 100 covers this way is around 1.1 megs a file. Now this is 2 to 4 times the file size of my previous settings but I feel like it’s worth it. What can I say? I love comic-book art and I love nice looking graphics. So it eats up some disk space? So what? To me -it’s worth it.

A word on DPI:

Notice how I no longer tie my size adjustment to DPI (dots per inch)? That’s because I finally figured out the truth about DPI. The truth is it’s a fairly antiquated old term that has little meaning in the digital age. Put simply DPI has NOTHING WHATSOEVER to do with a digital image’s (displayed on a PC, laptop, tablet, TV or phone screen) quality. It does NOT in anyway influence ANY of the following aspects of the file:

Detail Level
Image Quality
Compression
Resolution
File Size

So what the heck is it and whats it for?

Basically it is nothing more than instruction for a printer (or scanner). If you set the DPI for 300 then the printer will give you 300 DOTS PER INCH on the paper and the print-out will be pretty detailed. If you set it for 10 DPI the printed image will look AWFUL as it will only print 10 DOTS PER INCH on the paper. That’s ALL. The image as displayed on your computer screen will look exactly the SAME for both files. See here for a more detailed explanation (with a nice example too):

http://www.johnny-pixel.com/avm/dpi_confusion.php

Simply put Adobe should be ASHAMED of themselves for having Photoshop default to having DPI (called Document Resolution in PS) linked to file Pixel Dimensions in the Image Change dialog. What a confusing and STUPID default! Just remember if you NEVER plan to print your scans out then you can IGNORE DPI.

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