| 摘要 |
PURPOSE:To prevent recovery of ink receiving property in a retouched part for a long time by incorporating a compd. having mercapto groups or thion group and hydrophilic group in one molecule and desaltee arabic rubber. CONSTITUTION:The reparing agent contains a compd. having mercapto group or thion group, and hydrophilic group in one molecule which can almost instantly and surely make silver picture images hydrophilic, and desalted gum arabic. Water, alcohols or mixture solvent of these are used for the retouching agent. The gum arabic essentially consists of hemicellulose having a complicated structure and exists as salt of calcium, magnesium, potassium, etc. For example, a commercial gum arabic is changed into desalted gum arabic by dissolving, then exchanging the metal salt with hydrogen by ion exchange method, etc., and processing into a powder state by spray dry method, etc. With the obtd. retouching agent, accurate retouchment can be done and its effect can be maintained for a long time with excellent stability of the liquid. |
