Color conservation problems

Color Conservation Problems of an Early Twentieth Century Historic Dress... 

A particular early twentieth century dress (ca. 1906-1908) in Colorado State University s Historic Textile and Costume Collection evidenced some specific types of color damage. Since this garment was being restored as part of a Masters thesis project, the conservation problems posed by the discolorations were investigated. This chapter centers on the specific testing done to understand the reasons for the color problems. Preliminary and subsidiary historical investigations and the resultant restoration processes are reported elsewhere (1). 

Coloring of paper pulp is a problem which requires further study. As mentioned previously, most coloring agents used in commercial paper manufacture are easily faded by light. Many cannot be used under conditions of neutral pH. Those conservators fortunate enough to have... 

Such procedures would be considered to be appropriate, though not necessarily adequate, by most professional conservators. They look forward to a time when all aspects of the preservation needs of an item can be satisfied by safe treatments. So far, conservation scientists have not been able to help with answers for some very serious problems no research to date, for example, has provided guidelines as to how to prevent slight color changes in paper or media resulting from the application of alkaline solutions to arrest decay of the paper support. 

The work of Fox and Gex [Eqs. (17) and (24)] does represent a systematic approach to the problem, and their definition of mixedness (time when the last wisp of red color disappeared) is probably a conservative one. If the rash assumption is made that the results of different workers can be compared, the data of van de Vusse indicate that the results of Fox and Gex with propeller mixers would probably predict results for other agitator types within about a fourfold factor. While they are far from precise in a general way, these relations should be useful for rough estimates of mixing time. 

Figure 5. Cell division as a first-passage time (FPT) problem, (a) Schematic of stochastic cell size increase from a common initial condition. Between times t and T + At, the some growth tracks cross the threshold size, 9. Using probability conservation, the cumulative probability that the size is greater than 9 (above the black dotted horizontal line) must be equal to the complement of the cumulative probability that the FPT is less than or equal to T Oeft of blue dotted vertical line at t). (b) Scahng of the FPT distribution. The shape of the mean-rescaled division time distribution is timescale invariant, that is, independent of k, when there is a single timescale, 1 /if ocr, in the FPT dynamics. (See insert for color representation of the figure.)...

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