Image receptor contrast is expressed as what aspect of the D log E curve?

The correct answer is the slope of the D log E curve. The D log E curve, which represents the relationship between the exposure (D) to the image receptor and the resulting optical density (E), illustrates how changes in exposure influence the resulting density of the image.

The slope of this curve indicates how effectively the image receptor is capable of distinguishing different levels of exposure. A steeper slope signifies a greater contrast capability, meaning that small changes in exposure will result in larger changes in optical density. This ability to differentiate between various levels of exposure is key to producing an image with high contrast, making the slope an important aspect of image receptor contrast.

In contrast, the width of the curve relates to the range of exposures that can be accurately represented without significant loss of detail. The intercept shows the starting point of the curve where no exposure yields no density, and height is associated with maximum optical density the receptor can achieve. While these aspects provide valuable information about the imaging process, it is the slope that specifically measures the contrast performance of the image receptor.