這張圖片顯示的是康奈爾大學圖書館（Cornell University Library）的一本書的版權聲明頁面。該聲明指出，這本書的原版屬於康奈爾大學圖書館的館藏，並且在美國沒有已知的版權限制，這意味著任何人都可以自由使用這本書的內容。

此外，頁面還提到，這本書的重新印刷版本是根據 ANSI 標準 Z39.48-1984 生產的，這是一個專門用來確保紙張長期耐用的標準。此標準用於替換已經損壞無法修復的原始版本，並確保圖書的長期保存。

整體來說，這是圖書館為了保持文獻的完整性和延長其保存壽命而做出的保護措施聲明。

ANSI Z39.48-1984

ANSI Z39.48-1984 是由美國國家標準協會（ANSI）制定的標準，旨在規範「永久」或「檔案級」紙張的要求。這一標準主要用於確保紙張能長期保存，尤其在圖書館、檔案館等機構中，保存書籍、文件和印刷材料對歷史和研究至關重要。

以下是 ANSI Z39.48-1984 標準的主要特點：

1. 鹼性紙張：標準要求紙張的 pH 值在 7.5 到 10 之間，這意味著紙張是鹼性的，能有效抵抗酸性腐蝕。酸性是紙張隨時間變脆和變黃的主要原因。
2. 長壽命：根據此標準製作的紙張設計壽命可達數百年，確保紙張在長時間內保持良好狀態。這對於保存歷史文獻、學術論文和重要出版物至關重要。
3. 無木質素：紙張必須不含木質素（lignin）。木質素是木材中的一種天然聚合物，隨著時間的推移會分解，導致紙張變脆變黃。
4. 極少雜質：紙張必須盡量減少雜質，以避免這些雜質對紙張的耐久性造成不良影響。
5. 耐用性：紙張應能夠在日常使用中保持其物理完整性，不會因環境變化（如濕度和溫度的波動）而受到嚴重損害。

這一標準的制定具有重要意義，因為在此之前，許多紙張是酸性的，隨著時間的推移，這些紙張會變脆、變黃，甚至無法再使用。圖書館和檔案館採用 ANSI Z39.48-1984 來保存書籍、期刊和記錄，確保紙質材料能夠長久保存。

該標準後來經過修訂和更新，但其核心目標不變：為製作耐久、長壽的紙張提供指導，以確保檔案資料的保存。

ANSI Z39.48-1984 is a standard developed by the American National Standards Institute (ANSI) that specifies the requirements for paper that is considered to be "permanent" or "archival." The standard was introduced to ensure the long-term durability of paper documents, particularly in libraries and archives, where the preservation of books, records, and other printed materials is critical for historical and research purposes.

Here are the key features of the ANSI Z39.48-1984 standard:

1. Alkaline Paper: The standard mandates the use of paper with an alkaline pH level, typically between 7.5 and 10. This ensures that the paper is resistant to acid degradation, which is a common cause of paper deterioration over time.
2. Longevity: Paper produced under this standard is designed to last hundreds of years without significant deterioration. This is particularly important for historical documents, academic papers, and important publications.
3. Lignin-Free: The paper must be free of lignin, a natural polymer found in wood that can break down over time and cause the paper to become brittle and yellow.
4. Minimal Impurities: The paper should have minimal impurities, which can also contribute to its degradation. This ensures that the paper will remain in good condition over a long period.
5. Durability: The paper is expected to withstand regular handling and environmental factors like humidity and temperature changes without losing its physical integrity.

This standard was significant because, prior to its adoption, many types of paper were acidic and prone to degradation. Over time, such paper would become brittle, yellowed, and ultimately unusable. Libraries and archives adopted ANSI Z39.48-1984 to preserve books, periodicals, and records, and it became the industry standard for ensuring the longevity of paper-based materials.

This standard was later revised and updated, but its core purpose remains the same: to provide guidelines for creating durable, long-lasting paper for archival purposes.