Stitching: The Designer's Bane

by Joel Rodriguez

 

Let’s imagine the same scenario from two different perspectives.

 

Perspective 1:

You’re a comic creator, whether you’re new or have been in the game for a while, you’re working on a new project, and you’re nearing the finish line. Months of hard work and financial struggle are about to pay off. This book is your pride and joy; you want to do it right. You know little about graphic design and printing, so you decide to hire a professional graphic designer to produce and prepare your print files. You’ve been waiting for the files to come in, and they just hit your inbox!

PARTY TI–

Wait…You open the files and are stunned to see tiny white lines all over your beautiful cover art! They weren’t there before, but sure enough, there they are! Hairfine white lines around every logo, piece of text, and new asset. It looks like the cover had a knife dragged across it from every direction! How could this happen?! Didn’t you hire a professional?

You’re stunned, confused, and at a loss for words…

 

Perspective 2:

You’re a graphic designer. You’ve been in the industry for a while, you’ve done your time, made mistakes, but you learned along the way. You’ve been working on a project for a new client. From the calls you’ve had, you can tell they’re passionate about this new book. It’s their pride and joy; they want to do it right! They’ve come to you and trusted you with their book because they think you’re the best person for the job, and you want to deliver. You put your soul into the work, not because it’s your favorite project - but because it’s theirs, and you know how much it means to them. You produce the book, export your final print files, verify the print quality, and send them off!

PARTY TI–

Wait! An email comes back from the client. They are confused because white lines are showing up all over the cover—stitching: the bane of your existence. You feel like you’ve let them down, even though there’s nothing you could do. You try to explain that the lines won’t print, but they’re frustrated - they trusted you, yet now they’re confused about how this could happen. 

You’re defeated, frustrated, and at a loss for words…

 

----------------------

If you’ve ever felt the sting from either of those perspectives, welcome, my friends, to the wonderful world of STITCHING: THE DESIGNER’S BANE. In this post, I will give a not-so-brief breakdown of what stitching is, what causes it, how to check for it, and what it means for the printing process.

Warning: While I will do my best to explain these topics, this will be a long and technical post. If you have any follow-up questions, please leave them in the comments below, and we’ll answer them.

WHAT IS STITCHING? 

Stitching is a digital artifact, or false visual element, created by PDF reader programs when they cannot accurately render transparency effects over textured or colored backgrounds. These artifacts appear as thin (1 Pixel) white lines surrounding various elements on an image.

(For the sake of a consistent example, I will use this version of the Dusk County Chronicles logo to show the various effects and adjustments mentioned throughout the post.)

TERMS AND PROGRAMS

First, we have to define a few terms and uses to make sure we’re all on the same page.

 (Note: Throughout this article, I will refer to Adobe Creative Cloud Suite because it is the industry standard and the program suite MNS uses for graphic design and lettering. To my knowledge, the Stitching artifacts also occur in comparable free programs.)

Terms (Most to be further explained in future blogs):

- Raster: Artwork compiled using a pixel structure. Limited by resolution and dimensions - can only be scaled to a certain degree before pixels are visible to the naked eye (pixelation). Most often used for comic book covers and interior page artwork. Think of this as the foundation of a comic page.
- Vector: Artwork compiled using a mathematical equation connecting two points. Unrestricted by the pixel restraints and infinitely scaleable. Most often used for logo design, lettering, and typography for printed products. Think of this as the building blocks of the comic page - added to the foundation.
- Transparency: Aspects of a graphic element that exist yet are not visible.
- Layers: Graphic design software allows designers to place multiple images over each other within the same file, allowing for more advanced artwork possibilities.
- Flattening: Combining all layers within a file into a single locked layer.

 

Programs:

- Adobe Photoshop: Photoshop is the go-to Adobe program for raster artwork. This program is used primarily by artists to digitally draw, ink, or color interior pages and covers.
- Adobe Illustrator: Illustrator is the go-to Adobe program for vector designs. Graphic designers use this program to create assets that may need to scale throughout their lifetime or require a crisp, fine-line appearance. Logo designs and comic lettering are the most common uses for Illustrator in comics.
- Adobe InDesign: InDesign is a multi-page vector and raster layout and assembly program. While Photoshop and Illustrator can work for multi-page projects, InDesign was built for it. If Photoshop was peanut butter and Illustrator was jelly, InDesign is the bread bringing it all together!
- Adobe Acrobat (Reader/Pro): Acrobat is Adobe's PDF viewer program. They offer a free version called Acrobat Reader, and a paid version called Acrobat Pro.

 

WHAT CAUSES STITCHING?

 THE STITCHING EQUATION: Transparency + Flattening* = Stitching
(asterisk explained later - stick around!)

 

Part 1 - Transparency

Stitching is caused when an image containing transparent pixels over a colored background is flattened during or after being exported into a PDF format. A perfect example of this scenario is the effect of “Outer Glow.”

(Note: Stitching is caused by all transparency-related effects and techniques. I’m only mentioning outer glow for the sake of a consistent example)

When we place assets within any of the Adobe Suite programs, they are contained within frames: invisible boxes that constrain the asset and help with layout, alignment, and a host of other tasks. Think of these frames as the invisible border of the asset. The red box is the logo’s frame in the image below.

 

The “Outer Glow” effect creates a glow effect around your asset, as seen in the logo above. The glow is most substantial by the edges of your asset and gradually fades away as it expands. Now, here’s where it gets a little tricky and technical. While visually, the glow fades away; the actual effect extends all the way to the edges of the frame. It doesn’t look like it because the seemingly unaffected pixels are covered by transparent pixels from the glow effect to the frame.

 

 

Part 2: Flattening

You may be thinking: Cool story, but why do I only see stitching in SOME PDF files, and not all? And why is it most common in print files, the MOST IMPORTANT FILES?!

That leads us to part 2 of the stitching equation: Flattening. When an Illustrator or InDesign file is exported to PDF, it is, by default, exported with layers. This allows the file to be re-opened and edited, preserving the integrity of certain effects - such as outer glow. There are no stitching lines when a PDF file is exported with layers. The lines only show up when the PDF is flattened and all layers are removed (see the example below).

 

When a PDF file is flattened (which is possible through various techniques I’ll cover in a future post), the program has a tough time rendering the transparency pixels, so it makes the large file more manageable by breaking it into several smaller pieces. Think of it like a puzzle. The image is broken up into smaller pieces and placed with such precision that you never know the difference.

When flattened, the system breaks the transparent assets into pieces and replaces them in the same spot. However, it has to consider the full asset, not just the visible part. This means the “puzzle piece” edge follows the same placement as the asset’s frame.

 Now, your file has been broken into individual elements, each frame is its own puzzle piece, and it’s time for the system to put the puzzle back together - a piece of cake…to a degree. The system can easily reassemble the puzzle, but there’s a new problem. A new white line frames each piece at every junction where the pieces align - stitching.

This is not only why stitching appears, but it’s also why it always seems to be around the new assets placed on a cover file - logos, typography, etc. It outlines the frames of those new assets!

DOES IT PRINT?

In 99% of cases - NO. The stitching does not print. Stitching is a purely digital phenomenon caused by everything listed above. As scary as it can look, it does not affect the final physical product.

But what’s the 1%, and do I think you should be afraid? No, it’s not something to be afraid of, as I’ve only seen it happen 1-2 times in my career, and I was able to identify the root cause. 

From my experience, there’s only one scenario in which stitching will print: if the PDF file is uploaded into Photoshop or a similar program after it’s been flattened. When Photoshop imports an asset, it essentially loads what equates to a high-resolution screenshot of the item instead of loading the entire asset. Then it rasterizes (converts to pixels) that image import. Unfortunately, during this process, digital artifacts, such as stitching, are picked up by this import process and become real lines when rasterized.

In the few times I’ve seen this happen, it was because the printer’s process involved Photoshop or image processing via a similar “image upload” software. If that’s the case, there are ways around it, which I’ll discuss later - but this is definitely the exception, not the rule.

 

 

IS IT REALLY STITCHING?

 Anyone, creator or designer, can run a simple test to tell if the lines on their files are stitching or if there’s a real problem - and it’s free and can be done in under a minute. If you open your stitching-riddled PDF in Adobe’s PDF viewer program (Free = Acrobat Reader, Paid = Acrobat Pro), you can toggle one setting to determine if lines are truly stitching.

Stitching visibility is closely tied to an “Anti-aliasing” setting, which tells the PDF viewer to use extra resources to smooth out all the lines in an image. Anti-aliasing gives you the closest-to-accurate viewing of your PDF…and the graphical burden makes stitching visible. So, the easiest way to tell if the stitching lines are real is to turn off anti-aliasing. By turning off this one setting, your image will become a bit less sharp (especially around text), but all your stitching lines will disappear. Then, you just have to turn it back on, ignore the white lines that return, and go about your proofing process.

To do this, you will go into your PDF reader’s settings and uncheck a box called “Smooth Line Art.”

So, how do you turn it off? 

- Press Control+K (PC), Command+K (MAC), or navigate to “Menu/preferences” to open your file settings.
- Click Page Display
- Toggle the “Smooth Line Art” setting under “Rendering”
- Smooth Line Art Checked = Anti-Aliasing On
- Smooth Line Art Unchecked = Anti-Aliasing Off

 

WHY FLATTEN?

We’ve determined that stitching is caused by flattening transparent objects in a PDF, which begs the question - Why flatten the file anyway? 

Long story short, it’s because the printer needs it and will do it anyway. Some designers and creators have never seen stitching and have no idea what this post is even about. More often than not, it’s because they’ve never seen it - while their printer sees it daily. 

Some designers, especially in the indie comic book industry, either A - don’t use PDF exports for their final files and opt to just send loose TIF files to the printer, or B - use PDF but don’t flatten because the printer didn’t request it.

Flattening a file is part of the process for most, if not all, industrial printers, as it eliminates a host of possible complications (topic for a future post). So, most printers will run the file through a process called post-scripting, which flattens everything and prepares it for printing.

Some designers (Metal Ninja Studios included) do the post-scripting ourselves to ensure the quality of our client’s projects and make the process easier for our print partners. 

 

 

LET’S TALK ABOUT THE ASTERISK.

This has been a long post, and you’re a champ for sticking with me through the whole thing! If you remember back to the beginning, you’ll recall the stitching equation. 

Here it is again to save you a ton of scrolling:

THE STITCHING EQUATION: Transparency + Flattening* = Stitching
(asterisk explained NOW!)

There’s one scenario I’m aware of in which stitching does not show up on a flattened PDF file. That’s when the file is assembled in Photoshop, flattened within Photoshop (pre-PDF export), and then saved as a Photoshop PDF.

Through all my testing over the years, this is the only time that stitching doesn’t appear on a flattened PDF with transparent effects.

You may ask “if creating a PDF through Photoshop means no stitching, why not just do everything in Photoshop?”

Unfortunately, each Adobe Suite program has its own strengths and weaknesses. Photoshop is good for many things, but its weaknesses are why Illustrator and InDesign exist. The trio of programs covers all the bases a graphic designer needs. Excluding Illustrator and InDesign, to get rid of an artificial artifact is equivalent to entering a boxing match with both hands tied behind your back so you don’t scratch your gloves - you put yourself at a severe disadvantage to avoid a problem with no serious ramifications.

There may be a specific scenario where designers may have to build a PDF in Photoshop (such as the 1% situation mentioned in the “Does it print?” section above). Still, those scenarios should be treated as the exception, not the rule.

BEST PRACTICES - DESIGNERS.

I’m talking specifically to the designers now. Creators, feel free to skip to the next section if you’d like.

Designers, here are some best practices that I’d recommend when working with clients’ files:

- DO NOT get upset when your client asks about stitching. Think back to the scenario that opened this blog post. Chances are, they don’t know what stitching is. They trusted a stranger with their baby, and it came back with scars. You’d be freaked out, too, if you didn’t know what Stitching was. So take a beat, think about it from their perspective, and keep emotions out of your response.

-When sending print files, include a line briefly explaining stitching so your client isn’t surprised when they see lines on their file. Feel free to refer them to this post for more information. (metalninjastudios.com/stitching)

- If it’s suspicious, test it. I will assume you have the Adobe Suite, so open your file in Acrobat Pro and run the test I mentioned above. You’ll quickly identify stitching or anything that’s a legitimate issue that needs correcting.

- DO flatten PDF print files - while your client may not know the difference (aside from stitching), your clients’ printers will love you.

- DO NOT flatten digital files - since digital files aren’t being printed, keep them layered so your client’s readers won’t experience our bane - stitching!

 

 

BEST PRACTICES - CREATORS. 

Now for the Creators. Here are some best practices I’d recommend when working with designers:

- DO NOT get upset when a file has stitching or your designer doesn’t mention anything about it. I wrote this post as much for the designers as I did for you. Unfortunately, information about stitching is hard to come by. The only reason I know what I do is because I’ve spent hours upon hours digging through forums, talking to printers, and doing my own testing on files to try and find a solution. It seems like every day, I’m explaining stitching to people I assumed knew about it. There’s a chance that your designer may not know about stitching, or if they do, they may not understand the why behind it. While I can’t speak for all designers, I believe most approach every project with a love to rival your own. Not that they love the project as much as you do, but they love the joy you feel when you get your final product. They want to present the best product to you, and nothing is more disheartening than feeling like you disappointed a client because of something you can’t control and don’t understand.

- If it’s suspicious, test it. Download the free program “Acrobat Reader” and keep it close. Whenever you receive a PDF from your letterer or production designer, open it in Acrobat Reader and run the test I mentioned above. You’ll quickly identify stitching or anything that’s a legitimate issue that needs correcting.

- DO NOT review files in cloud programs. Nowadays, most file transfers happen in cloud programs such as Dropbox, Google Drive, or Box. These cloud programs are not meant for intense graphical review. Instead, they’re better suited for document review and stuff you’d run across in a general office. Whenever you open a flattened comic PDF in these programs, you will see stitching and a host of other graphical artifacts caused by the cloud program's limitations. Get into the habit of downloading your files and opening them in Acrobat Reader (or Pro, if you have it) to test for stitching and get a clearer picture of your file.

YOU MADE IT!

Wow! That was a lot. Thank you for sticking with me all through the end. I tried to keep this post as concise as possible, but it’s difficult when covering a topic as complex and technical as stitching. If you have any questions, please comment below, and we’ll do our best to answer them. If you’d like more explanation, tune into our monthly MNS team roundtables on Blake’s Buzz (1st Thursday of every month @ 8 PM EST) and ask your question(s) during our live stream for a more in-depth, personal response from myself and the rest of the team.

 

Now get back out there and get creating!

Joel Rodriguez

CEO, Metal Ninja Studios