PART 2.5 - IMAGE BRIGHTNESS / CONTRAST
Summary and quiz
The key concept within Part 2 was understanding the relationship between specimen density and image greyscale. Knowing that dense objects or structures appear as white and therefore low-density objects are black allows the viewer an instantaneous assessment of density alongside shape and form.
An appreciation of how X-rays are generated and how X-ray tube current and voltage may change image appearances are also critical to image interpretation. Similarly, the ability to digitally alter radiographs may mislead the viewer if the greyscale has been altered.
This section of the course links the above concepts together and presents the utility of photodensitometry as a method of quantitative analysis for estimating specimen density. This shall be explored further with specific reference to archaeology within Part 4.
End of Part 2 - Image brightness and contrast
The next part of this course is Part 3 - Radiographic Technique
Within the next part of the course you will learn how the positioning of the specimen and X-ray beam may affect image quality. More specifically, how radiographic appearances may be distorted due to geometric unsharpness.