Student I.D. No:
Section No.
Family Name:
Given Name:
INDUSTRIAL RADIATION TECHNOLOGY
IRT 223: INDUSTRIAL RADIOGRAPHIC TESTING
Instructor’s Name:
Semester:
Assigned Marks:
Day, Date:
10
Marks awarded:
EXPERIMENT 1
RADIATION – FILM PROPERTIES
Objective: To evaluate relationship between film speed and exposure time. To develops
understanding of industrial radiographic film properties including the characteristic curves for
various films. To learn, to calculate changes in film speeds while maintaining a constant
density of the radiograph.
Equipment:
1. Sensitometric chart.
2. Calculator
Theory: Sensitometric charts are comprised a group of curves representing the relative
sensitivity of various X ray films to exposure. The curves are plot of the film density versus the
logarithm of the relative exposure it must receive to reach a particular density.
Practical:
Using the sensitometric chart performs the following calculations:
Density of 2 was produced using type I film with an exposure time of 3 milliampere minutes.
A density of 3.5 on the same film is desired. Find the 2 density on the left of the chart; move
horizontally to film type I and then move down to the log relative exposure value at the base of
the chart. Repeat the above step to find the log relative exposure of density of 3.5. Subtract the
value obtained. Take antilog of this remainder values. Now multiply the original time to get
new exposure setting to achieve a 3.5 density of the same film. If density were to be decreased,
or if second faster film were used, the original exposure time would be divided by the exposure
factor.
Calculate the following:
1. If a density of 2 is produced using type I film and an exposure of 25 mA-minutes. What
exposure setting is required to produce a density of 1.5 using the same
film____________.
2. If a density of 2.5 is produced using type I film and an exposure of 8 mA-minutes. What
exposure setting is required to produce same density using the type II
film____________.
3. Using type II film a density of 2 is produced with an exposure of 11 mA-mints, what
exposure setting is required to increase density to 3.5 using the same film__________.
4. If a density of 1.5 is produced using type II film and an exposure of 8 mA-minutes.
What exposure setting is required to produce a density of 2.5 using the type III
film____________.
5. If a density of 2.25 is produced using type III film and an exposure of 21 mA-minutes.
What exposure setting is required to produce same density on type II
film____________.
6. Using type II film a density of 2.5 is produced with an exposure of 9 mA-mints, what
exposure setting is required to increase density to 3 using the same film__________.
7. If exposure of 5 mA-mins, produces a density of 2 using type I film what exposure is
required to produce density 2 using type II film ___________.
8. If a density of 2.4 is produced using type III film and an exposure of 26 mA-minutes.
What exposure setting is required to produce same density on type II film_________.
9. If exposure of 7 mA-mins, produces a density of 3 using type I film what exposure is
required to produce density 1.5 using same type film ___________.
10. If exposure of 14 mA-mins, produces a density of 2 using type I film what exposure is
required to produce density 2 using type II film ___________.
Conclusion: