Shop Talk - Our Man in Space halftone pattern demonstration. And scrubs!

So, today the P.A.G! mail room was inundated with a flood of one email about the Our Man in Space post from yesterday. A guy called Jack wanted to know how to create the "moire" pattern we used on our replacement space background. It's a trick the Phil Are GO! Graphic Blandishment and Photoshoppery Brigade use all the time to make the fake magazine covers and stuff like that, so why not show all of you in the peanut gallery how to falsify some vintage documents of your own? Hooray for visual dishonesty!

For those of you not interested in the nuts and bolts of graphical chicanery, you may want to look at Slate or something just now. Also, Liar Town USA is pretty funny if the news is too depressing. See you tomorrow.

For those of you who stayed, here's jack's electro-letter:

I was checking out the sci-fi book cover and noticed that you have chopped it into parts that we fellow designers can play with. I have to thank you for the “scrub” template – been trying to find a good one of those forever! My question is – how did you create the moirĂ© pattern on the purple background? I have been attempting to recreate that pattern for a while now to no avail. Any info you can offer would be pretty darn amazing! And thanks again!

Thanks for the kind words, Jack!

What Jack's talking about is this (see left). That grainy, screeny pattern?  That's called, in printing terms, a "halftone pattern". These are basically a way to simulate smooth gradients of tone with a limited selection of colored inks. 

If you ask Google about it, it will show you this:

History time!! Whee!!

But this idea is older than printed medium. If you think about it, this trick is basically what the impressionists were doing. You know that famous painting by Seurat? Yeah, that old thing. It's all dots, but when you step back, or squint your eyes, or just go slowly blind (as some impressionists were doing), it looks like smooth gradations of color.

Seurat used dots, but other impressionists used dabs of paint or short strokes. The point is, strategically selected (or "dithered") picture elements (later called "pixels"), can look like smooth color, even if you don't have an infinite selection of colors to paint with. Handy.
Printing generally uses four colors: Cyan, Magenta, Yellow, and Black, or CMYK. Your desktop printer may have more ink tanks than that, but that's their problem. Offset printing like magazines and stuff use CMYK almost without exception. They way they get the appearance of every color in the world comes down to scattering tiny dots of those four colors in a very clever way that tricks your eyes into thinking you're seeing millions of colors. The better the printing machine, the smaller the dots. Ink dots these days can be freaky small.

Yeah. History. Great. So anyway...

Back to Our Man in Space and his ball.

Here's a closeup of the book cover. The original is on the left. The space background was so obstructed by text that it seemed simpler to just paint up something similar than to try and rub out all the letters in the original. So, that's on the right. We painted the replacement using Corel's Painter, because of its excellent variety of brushes with virtual hairs and things like that. For simulated painting, Painter is The Shit. But, lots of people paint in Photoshop, which is fine, because most people haven't heard of Painter.

Supergeeks may notice that the "painted bg" layer is a "smart object". Turning the background into a S.O. just allows you to keep all the filters and effects re-editable later on. It also give syou the option to easily fade on or off the opacity of the effect you create. If you do what we're going to do to a plain old layer of pixels, the effects are permanent, and if you want to change them, you'll be relying on your history palette or "undo" function. Right click the layer and "Convert to Smart Object".

First thing to simulate the halftone pattern is to select the layer you want to filter in the layers palette (in ours, it's the "painted bg" layer) and go to FILTER/PIXELATE/COLOR HALFTONE.

You'll then see this dialog box. If you want to go mad and become unemployable, feel free to mess with the different channels settings. But basically, the "max radius" is all you need.

This is one of Photoshop's filters that doesn't give you a preview of the effect, so you'll be doing some trial and error.

Also, the size of the dots in the generated halftone pattern are based on the size of pixels in your image. You can't make them smaller than 4 pixels. In my experience, the resulting dots are almost always bigger than you want. So, you may want to crank up the resolution of your image if for no other reason  than to force the halftone pattern filter to keep the damn dots under control.

Anyway, set the "max radius" to 4 px and hit the "this definitely won't be OK but I have no real choice" button.

There! Perfect!


Here's where that "fade off your effect" thing becomes important. 

Now that you've added some filters to your Smart Object's layer, they appear as "Smart Filters" on the "painted bg" layer in the layers palette. You can double click the "color halftone" thing, if, god help you, you want the dots even bigger. OR... you can double click the little sliders icon to the right of that and...

Fade off the color halftone pattern to something like 20%, so it looks roughly similar to the original book cover, and less like Froot Loops arranged by an OCD child.

"There! We did it! We're totally perfect!" No, you're not done. Sit back down.

Digital filters nearly always come out looking far too sharp. They tend to look more believable with a little blur smeared over the top. Second verse, same as the first. FILTER/BLUR/GAUSSIAN BLUR.

This time, you do get a preview window. In clear defiance of the laws of the universe, you can apparently blur something by a fraction of a pixel. In this case, 0.4 seems about the right amount of blur, but it's also clear that the halftone pattern filter looks a little too faded off. Click OK on the blur and have a look at the layers palette.

Remember the sliders icon on the right side of the "painted bg" layer? We can mess with that again and up the opacity of the halftone pattern from 20% to 25%

One more thing: The order in which the effects are layered in the layers palette matters too. For example, if you've added the blur, but it doesn't look like it did anything, make sure the blur effect layer isn't underneath the halftone pattern layer. The halftone pattern can easily hide the blur effect if it's on top. Drag them around in the layers palette to re-sort their order.

After that, the halftone pattern looks pretty okay. I doubt a perfect match is possible, given the peculiarities of whatever offset print pattern happened to be used on the book versus the filter in Photoshop. It's possible that somebody with a deep, borderline sexual understanding of printing techniques could manipulate those individual color channel options in the halftone pattern filter's dialog box could get it perfect. However, this is fairly decent. It should pass a casual "sniff test" for digital mimicry.

As our thanks to Jack for asking a good question, here are some more transparent "scrub" PNGs, pulled from ancient paperbacks and magazines. Do what you want with them, Jack, but if your deceptive image fakery gets you in trouble, I don't know you.

One is from that Dragonslayer paperback we posted a few months ago, and the other is probably from a nineteen thirty-something copy of Popular Science Weekly. You're welcome!

Click for 1600 px.

Click for 1600 px.


Jack_Dayton_72 said...

You officially rock! Thanks for everything, Phil. I am putting this knowledge to use right now. I don't have a project to use it on....I am just wasting time learning at work! Oh, and a big +1 for the use of Painter! I used it when it was Fractal Painter about 100 years ago! Amazing program!

Jim D. said...

Daaang! Check out the brain on Phil! Thanks for showing us what goes into this work. I appreciate it more now.

Andrew H said...

For someone who even has trouble spelling tophoshop this is wizardry, pure and simple! Thanks for sharing the process.

PhilAreGo@gmail.com said...

Hah! Right you are. "Photohsop" is on my typo frequent flyer list. Blogger's spell checker flags Photoshop as incorrect, even when it's spelled right, and there's no way I've found to add it to the dictionary. Come on, Google! You gotta have my fingers' backs!

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