Printing Over Existing Images: A Complete Guide by National Wall Printers

One of the biggest advantages of modern UV wall printing technology is the ability to print directly over existing graphics, advertisements, and wall murals. Businesses frequently update promotions, branding, or messaging, and the ability to print over an existing image eliminates the time and expense of removing old graphics.

The National Wall Printers GT3200 Wall Printer, equipped with a 2-channel white ink system, is specifically designed to maximize coverage when printing over existing images. However, there are important design and technical factors that determine how effectively a previous image can be concealed.

This guide explains exactly what to expect and how to achieve the best results.

How UV Wall Printing Covers Existing Graphics

The GT3200 prints a white underbase layer beneath the full-color image. This white ink layer serves as a foundation that separates the original graphic from the new design.

This process allows the new image to:

• Maintain accurate color reproduction
• Appear bright and vibrant
• Reduce visibility of the previous image

Because the GT3200 prints two channels of white ink, it provides stronger coverage than single-channel systems commonly found in lower-end wall printers.

This makes it ideal for:

• Updating retail advertisements
• Changing restaurant menu walls
• Rebranding office interiors
• Covering outdated murals
• Refreshing commercial spaces

Why Design Choice Is Critical When Covering Existing Images

When printing over an existing graphic, design selection plays a major role in coverage quality.

Busier Designs Provide Better Coverage

Designs that include:

• Dark colors
• Detailed textures
• Complex patterns
• Photographic elements

…are far more effective at concealing previous images.

This is because complex designs naturally mask minor variations that could otherwise be visible.

Examples of excellent cover-up designs include:

• Brick textures
• Abstract art
• Dark gradient backgrounds
• Full-color photographic murals
• Textured branding graphics

These types of designs allow the GT3200 to produce clean, professional results when printing over existing images.

Light Colors May Allow Some Show-Through

Designs with large areas of light colors, such as:

• White
• Light gray
• Beige
• Pastels
• Soft gradients

…have a greater chance of allowing the original image to show through slightly.

This happens because lighter colors rely more heavily on the white underbase for coverage. Even with dual white ink channels, extremely dark or high-contrast underlying graphics can subtly influence the final appearance.

For businesses replacing advertisements, this is an important consideration when selecting new artwork.

Think of UV Wall Printing Like Painting Over a Wall

A helpful comparison is painting.

• Painting a dark wall another dark color provides excellent coverage
• Painting a dark wall with light paint may require additional coats
• Textured paint hides imperfections better than flat, light paint

UV wall printing follows these same principles. The white ink underbase provides excellent coverage, but the design itself determines the final concealment effectiveness.

Best Practices for Printing Over Existing Wall Graphics

To achieve the best results when using a UV wall printer to update existing advertisements or murals, follow these proven recommendations:

Choose darker or more complex artwork

Dark, textured, and detailed designs provide the strongest coverage.

Avoid large solid areas of light color when possible

Incorporating texture, gradients, or pattern improves concealment.

Increase pass settings when needed

Higher pass settings improve ink density and overall coverage quality.

Print on clean, stable surfaces

Dust, debris, or surface contamination can affect ink adhesion and appearance.

Test print when replacing critical branding

A small sample print ensures optimal coverage before completing the full wall.