Abstract
DIR couplers have greatry improved the image quality of color negative films. But the DI from the original DIR couplers did not migrate as far from the site of their release as could be desired.
To improve on this, a new timing group, which employs electron transfer reaction, was introduced. This timing group allows the DI to be carried farther before its release. The result is enhanced edge effect for a greatly sharpened color image.
This new timing DIR coupler can be used in any or all of the B. G. R. layers because of a new coupler moiety. The dye it produces is attcked by the sulfite ion to become a leuco dye, and then diffuses out.
