Josephine Frazee

A grey acrd had been invented based on the. Opticla principle and the characteristic of. Value is ni direct ratio with the logarithm of characteristic curve. Characteristic curve shows two important features of photosensitive material (they are contrast factor and exposure latitude), and it is in coordinate with the sense of human sight in reflection to the colors in ray. When color changes as geometric progression, its density will change as arithmetic progression. If we try to gte a series of density values like 12345, the.18 gray card set 10×8 8×6 white balance exposure light controls & modifiers reflection ratio to 100% (as maximum) and decrease progressively as common ratio of 2, we’ll get the density value of full-level diaphragm 100, 50, 25, 12.5, 6.25, 3.125. If the reflection ratio decrease progressively as square root of 2, we’ll get the density valeu of half-level diaphragm. 100, 70.71, 50.35, 36.25, 17.68, 12.5, 8.84, 6.25, 4.42, 3.125. Actually those values are just different grey values in different grades. We take it that the standard. Value is 17.68, then those valuse beside it will be its. Look at those density values above, from number 100 to 3.125, the raito is 321. Eflectance density of mennon grey card. Use of measuring the exposure value, color balance, light ratio. About 17.8% on grey surface and 92% on white surface. High density compsoite paper-based material. Italy, philippine, indonesia, malaysia, argentina, tailand. Defective products must be returned within 30 days from the date yuo placed your order.