4 Ply

4 Ply (Mat Board Thickness)

Overview

4 Ply refers to a standard thickness of mat board used in picture framing. A 4 Ply mat consists of four laminated layers of paper-based or cotton-based material, resulting in a total thickness of approximately 1/16 inch (about 1.4-1.5 mm). This is the most common mat board thickness in the framing industry and is widely used for both decorative and protective purposes in framing artwork, photographs, documents, and prints.

Construction and Material

4 Ply mat boards are manufactured by laminating multiple layers of material, typically paper pulp, alpha-cellulose, or 100% cotton rag. The top visible layer, called the facing paper, carries the decorative color or texture, while the inner core provides the mat's thickness and structural stability. The back layer, or backing paper, completes the lamination. Some 4 Ply mats are acid-free or museum-quality, designed to preserve artwork without causing deterioration over time.

Usage in Framing

4 Ply mats are the standard choice for most framing projects, offering both a clean aesthetic and protective spacing between the artwork and glazing (glass or acrylic). This air gap helps prevent the artwork from sticking to the glazing and adds visual depth by creating a border around the piece. Common uses include:

• Framing photographs, posters, and art prints
• Highlighting and isolating certificates or diplomas
• Adding color and depth to presentation pieces
• Protecting fragile works by creating a barrier from direct contact with glazing

Advantages of 4 Ply Mat Board

• Standard Thickness: Universally recognized and accepted in framing.
• Versatility: Works well for most artworks and photographs.
• Affordability: Less expensive than thicker mats like 8 Ply.
• Protective: Provides adequate spacing between the art and glazing.

Alternatives to 4 Ply

• 8 Ply: Double the thickness, offering greater visual depth and a more dramatic presentation.
• 2 Ply: Thinner mats used primarily for small works or as liners.
• Specialty Mats: Options like fabric-covered, suede, or textured mats for added design effects.
• Acid-Free or Museum Mats: Made with archival materials to protect and preserve valuable works.

Best Practices

• Always ensure the mat board is acid-free if the artwork is valuable or intended for long-term preservation.
• Match mat thickness with the size and weight of the frame for balance and aesthetics.
• Consider using 8 Ply or thicker mats for oversized pieces to prevent bowing or warping.
• When cutting mats, use sharp blades to achieve clean, beveled edges.

Related Terms

• 8 Ply
• Mat Board
• Acid Free Mat
• Ply