In flexographic printing, we love creative label designs that layer images and color, but things get tricky when transparent images are placed over backgrounds. Transparent images won’t trap to other elements in your design.
If you’re a designer, you don’t need to worry about trapping files yourself, but setting up your artwork correctly can make the process smoother and ensure your final label prints beautifully.
Here’s why transparent images can cause problems and how to fix them before your file reaches prepress.
Why Transparent Images Are a Problem
Trapping is the process of overlapping colors slightly so there are no white gaps if the stock shifts during printing.
When an image has a transparent background, our trapping software doesn’t have a defined color to work with. The program doesn’t know exactly where one color ends and the next begins.
So, even if your design looks perfect on screen, the software can’t calculate how to trap those edges. The result? Fine white lines, small gaps, or color mismatches around your image.
How to Fix It: Convert the Image for Trapping
To make a transparent image work in flexo printing, we must convert it to a solid image with a clipping mask and a filled background.
Here’s how that process works:
Step 1: Create a Clipping Mask in Photoshop
Open your image in Photoshop.
Create a new Alpha Channel and select the area you want to keep.
Delete that area from your alpha channel.
Invert the selection (Command/Ctrl + I) to define the background area.
Copy that mask (Command/Ctrl + A, then Copy).
Step 2: Paste into Illustrator and Trace
Paste the shape into Illustrator and size it to match your image.
Use Image Trace (set to Silhouette) to create a clean outline.
Expand the traced object, bring it to the front, and make it a Compound Path (Command/Ctrl + 8).
Select the image and path, then make a Clipping Mask (Command/Ctrl + 7).
Now you have a clean shape, but it’s still transparent.
Step 3: Add a Solid Background for Trapping
Go back to Photoshop and reselect the area around your image.
Contract the selection slightly (about 2 pixels depending on the resolution of your image).
Invert your selection to select the transparent area.
Use Content-Aware Fill to fill in that space.
This creates a subtle, color-matched fill behind your image.
Save and relink the updated file in Illustrator.
You’ll now have a filled image that looks the same visually, but under the hood, it has a solid background that the trapping program can recognize.
Why It Works
Adding this subtle fill gives the prepress software the correct information to overlap colors during trapping. The result is:
Clean edges
No white gaps
Smooth transitions between image and background color
Even though you can’t see the difference in your design file, this adjustment makes all the difference when your label runs on press.
The Takeaway
If you’re designing for flexographic printing, avoid sending files that rely on transparent backgrounds. Instead, use clipping masks and solid fills to ensure your artwork traps correctly.
These small steps help ensure your labels print beautifully without visible edges or color separation.
Watch the video below for a full demonstration of this process, including creating the clipping mask, filling the background, and setting up your file for trapping.
At Rose City Label, we take pride in helping designers and brand owners create stunning, press-ready artwork. If you’re unsure how to prepare a file, our prepress team is here to help.
You’ve done it. You’ve perfected your grandma’s secret sauce, found the perfect sustainable packaging, and are ready to share your creation with the world. The last step is the label—the beautiful, eye-catching design that will make customers grab your product off the shelf.
As your label printing partner, we understand that a beautiful design is only half the battle in a regulated industry like food and beverage. An incorrect label can lead to costly recalls or fines. While you have the final responsibility for designing and approving a compliant label, we believe in being an informed partner. We stay familiar with current regulations because the more we understand your world, the better we can serve you as your printer.
The FDA’s Must-Haves
Based on recent FDA guidance, every food label has a few non-negotiable elements. Ensuring these are correct on your final design is a critical step before you send your files to print.
Statement of Identity: The common or usual name of the food.
Net Quantity of Contents: How much product is inside, listed in both U.S. and metric units.
Name and Place of Business: The name of the manufacturer, packer, or distributor.
Ingredient Declaration: A list of ingredients in descending order by weight.
Nutrition Facts Panel: Required unless the product qualifies for a specific exemption.
Allergen Declaration: An explicit declaration of the nine major food allergens, such as milk, wheat, peanuts, and sesame.
Common (and Costly) Mistakes to Avoid
The FDA emphasizes a few key areas during inspections. A simple mistake in one of these areas can cause significant headaches for a food company. Keep an eye out for these common violations:
Undeclared Major Allergens
Misuse of “Gluten-Free” Claims: If you make this claim, the product must be tested and verified to contain no more than 20 ppm of gluten.
Incorrect or Missing Nutrition Facts
False or Unauthorized Health/Nutrient Claims
Navigating these rules can feel overwhelming. That’s why it’s so important to work with a dedicated legal or regulatory expert to get your label right before it comes to us for printing. As your printing partner, we have deep experience in the food industry, which means we understand your complexities. We’re committed to printing your final, approved design with the quality and precision your brand deserves.
Disclaimer: The information in this blog post is for informational purposes only and does not constitute legal advice. We are label printing experts, not lawyers. Please consult your legal counsel to ensure your labels fully comply with all applicable laws and regulations.
If you’ve ever sent artwork to print, you’ve probably heard the term bleed.
It’s one of those critical prepress details that ensures your labels look clean and professional once they’re cut to size. But what exactly is bleed, and how do you properly set it up?
Let’s examine what bleed means, why it matters, and a few practical ways to incorporate it into your artwork.
Why Bleed Matters
Bleed is the area that extends beyond your label’s final cut line (die line).
There is always a small amount of movement as labels move through the press and cutting die. Without bleed, this can lead to thin white edges or bare stock showing where your design ends too close to the cut.
The rule of thumb:
Any artwork within 1/16 of an inch of the die line should continue at least 1/16 inch beyond it.
That extra buffer ensures a clean finish, even if the die shifts slightly during cutting.
Simple Bleed Example
For simple designs, bleed is straightforward. Imagine a solid gray background that runs to the edge of your label:
Just extend the shape 1/16 inch past the die line.
In Illustrator, you can use Offset Path to build that extra margin quickly.
That’s it, bleed done!
Trickier Bleed Scenarios
Sometimes bleed isn’t so simple. Here are three common cases and how to solve them:
1. Raster Images (Photoshop Files)
If your artwork ends right at the die line and you need more image beyond it:
Open the file in Photoshop.
Expand your canvas by 1/8 inch.
Use Content-Aware Fill to extend the artwork into the new space.
Save and re-import the updated image into your label design.
It may not be perfect, but it usually blends seamlessly once printed and cut.
2. Vector Artwork
Vector files are trickier. The best option is to make the art bigger.
But if the artwork must stop at the die line, you’ll need to extend elements manually:
Select and stretch vector shapes carefully.
Or redraw parts of the design to push them past the edge.
This can be tedious, but it’s the only way to ensure proper bleed when resizing isn’t an option.
3. Mixed Artwork
For labels that combine vector graphics and raster images, you may need to use both methods: content-aware fill for images, and manual adjustments for vector shapes.
The Bottom Line
Bleed may feel like extra work, but it’s one of the most critical steps in preparing artwork for print. It prevents bare edges, ensures consistent results, and gives your labels a professional finish.
Taking the time to add bleed upfront saves you (and your printer) headaches later.
Watch the video below for a complete walkthrough, including examples of extending bleed in Photoshop and Illustrator.
At Rose City Label, we’re here to ensure that your artwork is print-ready so that your labels look as good in real life as they do on screen. Contact us for a quote.
If you’ve ever heard a printer talk about “trap” or “trapping,” they’re not talking about catching anything. In the world of prepress, trap is a technique used to make sure your colors line up correctly on press, so you don’t end up with unwanted gaps or bare stock showing through your design.
Here’s a simple breakdown of what trapping is, why it’s important, and how you can catch mistakes before your label goes to print.
Why Do We Need Trap?
As labels move through a printing press, the stock can shift ever so slightly. If two colors are butted right up against each other, even the tiniest movement can cause them to separate, leaving a thin white line where the stock peeks through.
Trapping prevents this problem by making the colors overlap just a little. That way, even if there’s a bit of movement, your design still looks seamless.
How Trapping Works
Light Colors Next to Each Other For example, cyan next to yellow. In prepress, we’ll add a thin line of yellow that overlaps into the cyan. It’s nearly invisible, but it gives us a safety net.
Medium Colors When two medium colors overlap, you may notice the trap a little more; it can appear slightly darker. Still, it’s far better than seeing bare stock.
Dark Colors Darker combinations are the easiest. With black, traps are basically invisible, and sometimes we’ll even set black objects to overprint entirely, which makes them richer and darker.
Overprint Preview in Illustrator & Acrobat
One of the best ways to catch issues in your design is by using Overprint Preview in Illustrator.
Go to View > Overprint Preview.
Unlike regular Preview mode, this simulates how inks will actually interact on press.
It gives you a more accurate view of your colors and helps spot problems early.
When proofing you can do the same thing viewing your pdfs in Acrobat or Adobe Reader.
Go to Preferences or Settings > Page Display > Use Overprint Preview: Always.
If your customer has this setting set they can catch problems too.
For example:
Black type set to overprint looks great.
But if you accidentally set white text (0% CMYK) to overprint, it won’t print at all. In Overprint Preview, you’ll see it vanish—giving you the chance to fix it before sending files to your printer. Change your overprint setting in Illustrator in Window > Attributes
The Bottom Line
Trapping may not be glamorous, but it’s essential for high-quality printing. A little overlap between colors prevents white gaps, ensures cleaner results, and saves costly reprints.
And by working in Overprint Preview mode, you can spot potential mistakes early, keeping your design production-ready.
Watch the video below to see trapping in action, with real examples of how colors overlap on press.
At Rose City Label, we sweat the details so your labels look their very best. If you’re not sure about file setup or want us to double-check your artwork, we’re always happy to help.
In a previous video, we explained how to design for metallic stock. The shiny effect comes from printing directly on metallic paper, which uses white ink to block shine where you don’t want it.
Foil stamping works differently. Instead of using metallic paper, we stamp metallic foil onto the label.
This requires a slightly different setup.
Step 1: Create a Spot Color for Foil
Select the object you want foiled (for example, a blue logo).
Make a new spot color swatch and give it a clear name, like Blue Foil.
Apply this spot color to the object.
This tells the printer exactly where the foil should be applied.
Pro tip: Always name your spot colors clearly to avoid confusion during production.
Step 2: Embossing Setup
Embossing is created in a similar way to foil:
Copy the same object and paste it in place.
Move it to a new layer and create a new spot color named Emboss.
Set the object to overprint so you can see how it interacts with the foil in your file.
Now you can toggle layers on and off to preview foil and emboss separately. For even more accuracy, open the Separations Preview palette and toggle on and off there. This will make sure your overprints are correct.
Key Things to Remember
Foil is positive. What you see filled with the spot foil color is what will be foiled.
Embossing is also positive. The filled area is what will rise off the surface. You can specify it as a deboss instead if you want the filled area to be stamped lower than the surface.
Always use spot colors (not process CMYK) for foil and emboss.
Keep each effect on its own layer to stay organized.
The Payoff
By setting up your foil and embossing this way, you:
Ensure your file is production-ready
Avoid miscommunication with your printer
End up with labels that look polished, professional, and truly stand out
Watch the video below for a full step-by-step walkthrough in Illustrator.
Need help making your labels shine? The Rose City Label team is always here to answer questions and make sure your artwork is press-ready.
