Tuesday, 13 February 2018

Paper to Pixel To Paper Again Addendum D: Working in Color, Part 3

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A guide to creating the best looking line art in print in the new digital print world

Addendum D:
Working in Color, Part 3

This is the second addendum to Paper to Pixel to Paper Again, a series that explains (in an overly thorough manner) the how-to's of preparing line art for print.

And as always, if you have any questions, please let me know in the comments!


Are You Telling Me We're Going to Get Through an ENTIRE INSTALLMENT of This Series Without Mentioning Sharpening??!

Everything we've done so far has been intended to address the stages of the work we've already gone through. That is, the color adjustments and the 180 degree rotation are because of the limitations and the mechanism of the input/scanning stage. Now we're going to make a few adjustments based on the next steps instead.

First off, this is probably the third time that I've recommended it, but if you're interested in these topics, do yourself a favor and find a copy of the classic REAL WORLD Image Sharpening by Bruce Fraser and Jeff Schewe (plenty of $10 copies at a certain South-American-themed website.) Although I disagree with several of their conclusions, particularly regarding resolution and supposed importance of noise reduction, it's an invaluable resource for anyone working for color reproduction.

Using the language of REAL WORLD Image Sharpening, we're first going to do just a bit of "capture sharpening". That is, we'll do some very mild sharpening to counteract the inevitable softening effect that any optical capture system exhibits.

PERIODIC NEUROTIC REMINDER—If your source image has any iterative mechanical pattern, such as screen tone, or scans of previously-halftoned material, DO NOT DO THIS STEP. You'll need to address it in some other way before proceeding.

Here's an adjusted scan of an illustration of mine from last year. As I typically do, I scanned it at-size at 600 ppi RGB, then adjusted the Levels with the original in my hand, side by side with the monitor.

(In this case, I also "cheated" a bit on the figure, adjusting his skin tone separately from the rest of the image, as he had a rather lifeless pallor in the original).

So! Time for the "capture sharpening". Let's zoom in way too close.

Yeah, like I said, WAY too close. Click to see it at 100 percent.

You can see some of the (totally normal) softness in the scan. Those streaks of red are from a water color pencil. They should have a bit of grit to them.

Because there's not really any noise per se to bring up in a painting like this — no undesirable texture etc — we can get away with applying a healthy dose of sharpness, using the Unsharp Mask tool.

 And here's the result. Click it to enlarge and see the image at 100 percent of the scan size.
Okay! Having sharpened things up, we're now going to resize our image for our destination.

If you're placing this image in a layout that has more than one image or graphic additions, go ahead and place your image now, and shrink or enlarge at will within your graphics program, finding out the optimum size within the layout.

Once you know what it is, open your original again in Photoshop and hit Ctrl-I to bring the Image Resize menu up.

Click the dropdown boxes until you have the "Percent" value revealed. In my case, I'm going to shrink this to 60 percent of the original size. Enter that value in your Percent box. If you're reducing in size, select Bicubic as the method (In my experience, Bicubic Sharper can make things way too crispy). Lastly, if you're not already there, enter your target resolution. As mentioned before, if you're printing on coated paper, I'd recommend somewhere between 400 and 600 ppi. (You'll notice the Percentage value might change if you change your target resolution. It's just doing the math for you, what the actual pixel change will be, not just the dimensional change).

When you're ready, hit "Ok".

Now that we're actually in the resolution space of the final files, it's time for our final blast of sharpening. In the parlance of REAL WORLD Sharpening, this is our "output sharpening" phase.

If our first round was targeting the high frequency information (small details), this is a grosser layer, trying to prepare for the softening effect of the halftoning that the image will experience when it's printed. As such, you'd be wise to back off the Threshold somewhat so the sharpening is effecting less of your image, and raise the Radius a bit from the modest setting we had before.

Please note — if your finished document will be printed on a Xerox all-in-one at your local Office Depot or Fedex Office, those machines are set to automatically apply this kind of output sharpening to documents. So you can either skip this step or ask them to turn off the sharpening on their interface when printing! This stuff can look harsh and crispy if it's overdone.

It's my experience, however, that the reverse is usually true. People don't tend to apply enough because it can look a little odd on screen. But it's what you need to blast through that softening printing screen!
Here's a close up of a scan of one of Dave's paintings that was turned into a bonus print for one of the first Cerebus Archive Kickstarters. It's a pretty soft scan.

And here's the pretty crispy file I sent to the printer, with two stages of sharpening, as detailed below.

And here's an up-close scan of the final print, half-tone dots and all. Notice how the haloing and strange crispiness has disappeared in the print, eaten up by the inevitable softening of the printing process.

What's Next?

Save your optimally-sharpened and resized image and replace the scaled version in your layout program. Now it's time to output your layout to PDF!

(Seriously, get REAL WORLD Image Sharpening and read the whole thing. And for goodness sake's, don't let your sharpened copy be anything more than a COPY of the original file. Things are changing fast, and you don't want to be stuck with an unnecessarily crispified image at some point in the future!)

Next: Is That All You've Got, Seanny Dude?

1 comment:

Anonymous said...


Thanks for your updates and sharing your essays. Good luck with your career!

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