CH 21 Film Sensitometry

Question 1

Film Sensitometry

Answer 1

The measurement of the characteristic responses of the film to exposure and processing.

Question 2

Penetrometer

Answer 2

Step wedge, series of increasingly thick, uniform absobers.

Question 3

Penetrometer is usually made out of:

Answer 3

Aluminum, sometimes plastic.

Question 4

Penetrometer is not recommended for?

Answer 4

Quality Control testing equipment purposes.

Question 5

Uses for a penetrometer is to?

Answer 5

Monitor x ray equipment, including intensifying screens.

Question 6

Sensitometer

Answer 6

Used to expose a reproducible, uniform, optical step wedge onto a film.

Question 7

A sensitometer uses a

Answer 7

Controlled intensifying light source and a pulsed stroboscopic light.

Question 8

Sensitometers are available in:

Answer 8

11 to 21 step versions.

Question 9

11 step increases intensity by

Answer 9

100%

Question 10

21 step increases intensity by

Answer 10

41%

Question 11

Densitometer

Answer 11

An instrument that provides a read out of the amount of blackening on a film.

Question 12

Densitometer properties are:

Answer 12

1)Calibrated light source 2)Stage for placing film 3)A light aperature 4)Sensor arm with optical sensore 5)Read out display 6)Calibration control

Question 13

Calibrating the Densitometer prepares it for:

Answer 13

it’s reading, it will measure the differences of density between the calibration intenisty and the intensity of the light the beam is transmitting.

Question 14

Optical Density Numbers

Answer 14

The logarithmic number range displayed by the Densitometer.

Question 15

Optical Density Formula

Answer 15

OD=Log10(Io/It) Io=Intensity of the incident light It+Intensity of transmitted light

Question 16

An increment of .3 on the logarithmic scale represents a

Answer 16

Doubling of exposure

Question 17

Films ability to stop light:

Answer 17

Opacity

Question 18

Opacity formula

Answer 18

Io/It

Question 19

The D log E curve is AKA

Answer 19

Log exposure, H&D Curve (Hurter and Driffield), Characteristic Curve, Sensitometric Curve

Question 20

Base Plus Fog

Answer 20

The area of film w/no exposure, the density at no exposure.

Question 21

Density is always ____ on film.

Answer 21

Inherant

Question 22

Radiographic film base densities range from OD:

Answer 22

0.05-0.10

Question 23

Base Plus fog should not exceed?

Answer 23

0.22

Question 24

On a D log E curve the bottom of the curve represents:

Answer 24

The Base Plus Fog

Question 25

Above the Base plus fog on the D log E curve the

Answer 25

Toe is found.

Question 26

What portions is between the Toe and the Shoulder?

Answer 26

The body, usually straight line due to linear reactions.

Question 27

The shoulder aread of the curve represents the:

Answer 27

Darker more dense areas. (Hydroquinone)

Question 28

The darkest aspect of the curve is found at the

Answer 28

Dmax

Question 29

The toe is controlled by

Answer 29

Phenidone

Question 30

D log E curve low ranges

Answer 30

OD 0.25-0.50

Question 31

D log E curve high ranges

Answer 31

OD 2.0-3.0

Question 32

Most OD diagnostic quality densities are between

Answer 32

OD 0.5 and 1.25

Question 33

Curve reversal or solarization occurs when:

Answer 33

OD has reached Dmax however exposure continues, ionizing the silver atoms attached on the speck causing them to repel. This produces less density.

Question 34

Hydroquinone controls what color tones?

Answer 34

Black tones

Question 35

Phenidone controls what tones?

Answer 35

Gray tones

Question 36

Dmax

Answer 36

max density a film is capable of recording

Question 37

4 Film Characteristics

Answer 37

1)Resolution 2)Speed 3)Contrast 4)Latitude

Question 38

A change in density will only affect contrast when=>

Answer 38

Above or below the straight line portion of the curve

Question 39

Latitude

Answer 39

A range of exposures that will produce densities with in the diagnostic scale

Question 40

Latitude formula

Answer 40

Eh-El=Latitude, Eh=high exposure, El- low exposure point.