Photographic and cinematic methods in work study


In the case of detailed investigation at a workplace where the operations may be of very short duration, or performed at a high speed or where several different jobs are being carried out simultaneously the observer is frequently unable to perceive movements accurately enough for recording purposes. In such cases, photography can be used for recording and examining. It is also used when conditions like wetness or dirt make it difficult to write down a record. It is also used when there is an element of danger.

Both still and cine photography are employed for this work.

The following are advantages of photography:

1. A permanent record is obtained of the work being studied.

2. The record can be referred to at any time, in any place and by number of people.

3. An excellent means is obtained of demonstrating differences in method. This is a valuable aid in training.

4. Reproduction of the original method is possible at any time after the improved method has been installed (This is useful when the degree of improvement may be disputed)

5. Repeated study of worker’s activities can be made without disturbing him at frequent intervals.

6. The examination of intermittent work can proceed when the work itself is not actually in progress.

The “Polaroid� type of camera which gives the finished print in a minute is very useful.

Use of Cine Films

Cine films possess a number of features as compared to visual inspection:

1. They can be projected to any required speed and can be stopped at any convenient point.

2. They can be run backwards, which sometimes enables clumsy or backwards movements to be more easily detected.

3. Permit greater detailing than eye observation.

4. Provide greater accuracy than pencil, paper and watch techniques.

5. Are more convenient.

6. Provide a positive record.

The following are the ways in which films are employed

Micro-motion Studies

Two handed process charts, simo charts, cycle graphs and chrono cycle graphs are used for the study of operations at the workplace. The last of these four is main technique of micro-motion analysis, which is concerned with the most detailed aspects of methods improvements.

Micro-motion analysis is expensive to conduct, and should be undertaken, if it appears economically justifiable, only after large scale improvement has been fully investigated as a result of using the other recording techniques.

In certain types of operations, particularly those with very short cycles which are repeated thousands of times (such as the packing of sweets into boxes or food cans into cartons), it is worthwhile to go in much greater detailed studies to determine where the movements and efforts can be saved and to develop the best possible pattern of movement thus enabling the operator to perform the operation repeatedly with a minimum of effort and fatigue.

The techniques used (usually filming) are collectively known as MICROMOTION STUDY.

The micro-motion of techniques is based on the idea of dividing human activities into divisions of movements or groups of movements according to the purpose for which that are made.


Therblig is the name given by Frank B Gilbreth to each of the specific division of movement, according to the purpose for which it is made. These therblings cover movements, or reasons for the absence of movement. Each therblig has specific color, symbol, and letter for recording purpose.

Originally, Gilberth created seventeen Therbligs, but later, in the 1940s, ASME revised this and added the therblig ‘Hold’. With the exception of the letter code identification, which is not often used, there are eighteen therbligs.

Given an equal facility with process charting and therbligs, the practitioner is better able to make a proper choice in what is the most efficient tool for his purpose. Sometimes, process charting is all that is necessary; at other times, a time scale may be desirable, or fine detail may have to be recorded, in which case therbligs have more to offer. The only technique that can be offered as suitable alternatives to therbligs in situations governed by human movement are a predetermined motion time system s MTM, or Work Factor.

In its simplest form, therblig symbols can be used in place of process chart symbols, to produce a therblig chart. This can serve much the same purpose as a flow process or two-handed process chart, and although it may seem that greater detail can be portrayed in this way, the absence of a time scale makes this advantage dubious. On the other hand, a therblig chart is often used as a first step towards the construction of charts that do possess a time scale, in which case the method of gathering data must possess a means of identifying each therblig and its duration.

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