Colours of physical origin in dyed silk

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Archives of Applied Science Research, 2014, 6 (4):136-138
(http://scholarsresearchlibrary.com/archive.html)
ISSN 0975-508X
CODEN (USA) AASRC9
Colours of physical origin in dyed silk
Mitali Konwar1, Priyankshu Protim Deori2 and G. D. Baruah3
1
2
Digboi Mahila Mahavidyalaya, Digboi, Tinsukia, Assam
Kalinga Institute of Industrial Technology, KIIT University, Bhubaneswar, Odisha
3
Centre for Laser and Optical Science, New Uchamati, Doom Dooma
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ABSTRACT
The present work reports the observations made on a collection of twenty specimens of dyed silk of Assam
procured for the study related to the spectral characteristics reflected by the dyed silk in a variety of
colours to suit different tastes. It is worthwhile to note that there is a direct relationship between the
brightness of different colours as observed by a spectroscope and the quality (cost) of product. The aim of
the present work is to set out in a systematic manners the methods and results of the experimental
investigations on various aspects of the superposition of colour of physical origin. It has emerged from the
studies that the observations of the spectral characteristics shall prove to be handy in silk industry in
Assam.
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INTRODUCTION
The superposition of colours in different sectors of the visible spectrum (VIBGYOR) is a topic of considerable
interest both theoretic and as well as experimentally. It may be no Hut light appears simultaneously in different
parts of the spectrum is perceived by our eyes. This fact was investigated by Sir C. V. Raman (1 several
decades ago. Raman discussed in detail the basic facts and principles relate to the perception of the colours
of the composite lights. It is however not without interest to consider innumerable cases of practical
importance and to show how they illustrate the ideas regarding the phenomenon of the superposition of
colour. There are a great variety of such cases which could be discussed and examined critically. We must
emphasize here that the phenomenon of colours depends considerably on the physical world around us. For
example we usually discuss the colours soap films and as on. They are produced by interference. But the
main topic to be remember is that it depends on the observer. According to Feynman [2] physics characterizes
the light that enters the eye, but after that our sensations are the result of bhoto chemical - neural brocesses
are psychological responses. There are many interesting phenomena associated with vision, which involves a
combination of physical phenomena an physiological process and the full appreciation of natural phenomena,
as we see them, go beyond physics. Many interesting phenomena bridge the gaps between different fields
or subjects created to us. With this remark we note that colours photo a enormously important role in
human life and activity, and the production of objects exhibiting colours is a substantial part of industry
created by human and in fact we cannot think of any material without colour. The dyeing of textiles and
silk cultivation may be mentioned as an outstanding examp of the kind. Such activities create a demand
for the precise specification of colour and for methods by which colour exhibited by various materials can
be subjected to peruse comparison and measurement. There is also demand for the reproductions of colours
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Arch. Appl. Sci. Res., 2014, 6 (4):136-138
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by specialized technique and particularly by photography and the wide use of such reproductions by the
art of colour printing. To deal with these aspects in detail we would need more than one treatise. We shall
therefore restrict our discussion to the specific cases of dyes and textiles of Assam. The colouring of
textile materials by the use of dye-staff is an art which dates back to the remotest antiquity. The
development of synthetic dyes in great variety on the on hand and of new textile materials by chemical
processes on the other hand has much enlarged the domain of such activities, As a result, textiles group a
group of human made products exhibited a great range of colours. From these objects it is possible to
obtain a deep insight into the relationship between the perceived colour and the physical characteristic of
the light reflected or diffuses by the materials. In the present work we have also indicated a possible
correlation between the brightness of the colour and the cost the silk materials. It is worthwhile to note here
that we have followed the procedures and the ideas adopted by Sir. C. V. Raman several decades earlier
[1]
MATERIALS AND METHODS
Assam is well known as a producer of of dyed silk in variety of colours to suit tastes. A collection of
twenty specimens of silk covering a whole range of hues was procured for the study. We have only used
a pocket spectroscope (model ASCO). The observer has only different samples one after another again
bright light (preferably sunlight) the reflected radiation. The colours perceived by the eyes, brightness of
the light observed and other characteristics are recorded visually and the data are tabulated as shown in
Table 1.
Table 1 Spectral characteristics of a group of Assam silk, The instrumental used is a hand spectroscope
Colours
V
I
B
G
Y
O
R
Samples
1
VVW
VVW
VW
VW
VS
W
W
2
VVW
VVW
VW
VW
VS
W
W
3
VW
VW
VW
VW
VS
W
W
4
VW
VW
VW
VW
VS
W
W
5
VW
W
W
W
W
6
W
W
W
W
W
W
W
7
W
W
W
W
W
W
W
8
W
W
VW
VW
W
W
MS
9
W
MS
MS
W
W
W
W
10
VVW
W
W
W
MS
W
W
11
VVW
VVW
VVW VVW MS
W
W
12
VVW VVWW VVW VVW VS
MS
MS
13
W
W
W
W
MS
MS
VVW
14
W
W
W
MS
MS
W
MS
15
VW
VW
VVW VVW
W
W
VVW
16
VW
VW
VW
VVW
W
V
VWW
17
VW
VW
W
W
MS
MS
MS
18
MS
MS
VW
VW
W
VVW
W
19
VVW
VVW
MS
MS
MS
VW
VVW
20
VW
VW
V
VVW
W
VVW VVW
W = Weak, VW = Weak, VVW = very very weak, S = Strong, MS = Medium strong, VS = Very strong
RESULTS AND DISCUSSION
Table 1 may be considered as the summary of the work carried out by the authors. There are lot of
physics along with on topics of interest like physiology. However, going into detail about the subjects
involved we would like to indicate the practical importance of the procedure adopted in the present. In the
present investigation we have used 20 samples of Assam Silk. This was the procedure adopted by Raman
[1] many decade ago to observe and estimate the intensities spectral lines from the spectrograms. Needless
say that the present work may be supplemental by more sophisticated intensity measurement instruments
commercially available. But, as have already indicated earlier, colour depends primarily on our eyes. Up till
now no instrument has been able to replace fully the role of the eye. Table 1 include the intensities of
the visually estimated reflected light in seven sectors (VIBGYOR) the spectrum. As may be inferred from
this table the intensities greatly differ. This is the direct result of the procedure used. We may observe one
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salient feature which needs to be emphasized . The intensity of the yellow sector is relatively strong in all
the samples introduced in the present investigation. Specifically for samples 1 and two the intensities of
the yellow sectors are very strong. There is a correction of this with the fact that the cost of samples 1
and 2 are sufficiently more as compared to other samples. From what has been briefly discussed above it
is worthwhile to make a conclusion with a limitation. Whatever discussions we have made are nothing but
the generalization of the accepted theory of colour vision that is colour depends intensity. If we go into
the dark room from a brightly lighted room, we usually cannot see very well for a while, but gradually
the objects become more and more apparent and eventually we can see something where we could see
nothing before. When intensity of the light is very low the objects we could see have no colour. This is
a different subject but this is related to the present work also.
CONCLUSION
It is reasonable to believe that visually estimated spectral characteristics as observed through a pocket
spectroscope may be used to classify different samples of dyed silk of Assam.
Acknowledgement
The author (Dr.Mitali Konwar) is grateful to UGC for the award of a research project No.F.5-76/201314/(MRP/NERO)/17412
REFERENCES
[1] Sir. C. V. Raman, The Physiology of vision, The Indian Academy of Science, Bangalore (1968).
[2] R. P. Feynman, R. B. Leighton and M. Sands . The Feynman Lectures on physics, Vol 1, (Eleventh
Reprint) 2001. Narosa Publishing House.
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