Digital Light & Color

I orignally bought Picture Window Pro years ago for digital photography pp, and I still use it for that and all is well as far as that goes. However, this time I'm using it for something different.

I'm scanning line-drawing artwork to use as spot illustrations in books. For Kindle and other eBooks, resolution needs to be low or else the image will appear way too big on the eBook reader. For print books, i.e. paperbacks and hardcovers, resolution needs to be much higher or the images will look soft and blurry.

I've found that if I scan these line drawings at 150dpi, that's a great size for eBooks. They look about as crisp and clear as I could hope for in that resolution.

But that's too low resolution for a print book. For a print book I'd like about 600dpi, or even 1200dpi if it doesnt cause the book file to exceed the maximum allowed.

If I scan at the higher resolution and then resize it down, the result is soft and blurry. I've tried working with the sharpening parameter in PWP's resize feature, but no matter what I set it on, the results are not good compared to scanning at 150dpi.

I'd prefer to start with one scan of each image if possible rather than doing separate scans for eBooks and print books. It isn't just a matter of scanning time; I also have to do some repair and other tweaking on each scan. Having to do two or more scans per image would mean repeating that work for each source image.

Do I need to make separate scans for eBooks (150dpi) and print books (much bigger)? Or can I do this with a single large source scan per image? How can I downsample to 150dpi while retaining all the sharpness and clarity I see if I start out with a 150dpi scan - or can I?

Greg,

I can think of a couple of things you might try, but without seeing an example of what you find acceptable, it's hard to know if I am on the right track. I assume when you are downsizing the image, you are using the default bicubic interpolation method, which is a source of the blurriness. So you might try --

(1) When you downsize the hi-res line drawing, instead of using the default bicubic interpolation method, just use the nearest neighbor one.
(2) If it's mostly a high contrast black-white image, make a mask of the of the black lines, feather it with a +1 feather in step mode, invert and save the mask, then downsize it to get the lo-res image.

If you can figure out a way to post some samples (a piece of the hires scan, a piece of the low-res scan), it might help.

Good luck,
Bob W

The effects of the sharpening parameter in the resize transformation are very subtle. Try using the sharpen transformation after resizing - usually either the sharpen or heavy sharpen options work best.

Hi Bob & Jonathan,

Thanks, both your ideas -- resizing using nearest neighbor instead of bicubic, and sharpening afterwards -- worked great. I would have been very happy with the results using nearest neighbor, but using bicubic and then doing heavy sharpen at 100% looked even a bit better.

Since both looked good separately, I also tried using both nearest neighbor and then sharpening, but that did not look good.

I'll post the result here. I had to crop it to meet the max posting size here.

Greg

The other useful technique is to use the special effects/high contrast transformation on the image right after you scan it.

A brief digression in praise of Special Effects | High Contrast for a different purpose. It is such an easy, effective way to create a mask of bright areas. As good or better than a mask made by brightness stair step.

There are many bits of PWP lore that should be in one place, perhaps a grab-bag Tips and Tricks section of the electronic manual.