To compare brightness judgment, we conducted two experiments. In the first one, the observer evaluated the brightness of a space while within it (“observer's space”) by determining the illuminance of another room which gives an impression of equal brightness to that of the “observer's space”. In the second one, the observer evaluated the brightness of a space while looking into it through a small window (“observing space”). We also examined the influence of the lightness of the interior wall of the space and the existence of white paper upon brightness judgment in both situations. Results showed that the brightness of the “observer's space” was judged higher than that of the “observing space”. White walls were evaluated as brighter than black walls in both the “observer's space” and the “observing space” while illuminance of the space was kept constant. A space was judged brighter with a piece of white paper than without it especially in the “observing space”, which indicates the effect of white paper is eminent in the condition.
In 2004, CIE issued a technical report (CIE 157: 2004) entitled "Control of Damage to Museum Objects by Optical Radiation," in which it recommended that materials classified as highly responsive to light (ex. blue wool standard 1 to 3) be exposed for a maximum of 15000 lx·hr/yr. The aim of this report is to validate the new CIE recommendation for natural yellow dyes categorized below the blue scale grade 4. Twenty types of natural yellow dyes on silk were exposed to both white and non-UV fluorescent museum lamps. Color differences were measured at 15000 lx·hr (500 lx at fabric surface x 300 hr) intervals for 10 times, for an accumulated exposure totaling 150000 lx·hr. The results show that non-UV fluorescent museumlamp was 24% more effective in reducing the fading rate compared with white fluorescent lamp. Complying with the new CIE recommended maximum exposure of 15000 lx·hr/yr, the fading rate for most yellow dyes, will be below the noticeable fading degree (ΔE1.6) thus, the CIE recommendation is valid. However, additional dyes should also be classified as "extremely highly responsive." The limiting exposure for Ukon (Turmeric, Cucuma longa L., colorant: curcumin) should be 3500 lx·hr/yr, and Kihada (Amur cork tree, Phellodendron amurencse Rupr., colorant: berberine) and Onion skin (Allium cepa L., colorant: quercetin) should be 8000∼12000 lx·hr/yr. This study demonstrated a need for revised classification of "extremely highly responsive" materials under museum lighting conditions.
Super-high-pressure mercury discharge lamps have been used as UV light sources in the photolithography exposure process. It is well known that these lamps applied internal pressure is more than 1MPa and the outer bulb temperatures reach over 500°C. Thus, the safety for rupture of the lamps has been a very important issues in their design. In this study, the effects of the following two factors on the rupture characteristics of the sealed parts were investigated experimentally, (1) joule heating in the current operation, (2) heat conduction from the discharge. In addition, the finite element calculation (FEM) was carried out to investigate the stress distribution in the sealed parts. The experimental results showed that the rupture occurred in the cooling process when the maximum temperature of the sealed parts was more than 1200°C. The numerical results showed that the maximum value of the maximum principal stress σ1 occurred near the point where a rupture initiated in the experiments. In addition, the experimental results were in fairly good agreements with the FEM results. The authors proposed that the maximum temperature of the sealed parts should be less than 1000°C during operation to prevent the lamp rupture.