College and Research Libraries


By J O H N O . K R A E H E N B U E H L 

Library Table Lighting 
In an article in the June, 1941, issue of 

College and Research Libraries, Prof. 
Kraehenbuehl outlined basic principles of 

library lighting. The following article is 

a report on a series of experiments with 

fluorescent table lamps. 

IL L U M I N A T I O N of the tables in the read-ing and reference room is the most im-
portant lighting task in the library. A t 
this position a worker may spend many 
hours using the eyes continuously at a 
very difficult and concentrated task of 
seeing. If the lighting is insufficient or 
the lighting quality is poor the expenditure 
of nervous energy may be such as to cause 
an excessive fatigue which if continued 
may lead to serious organic disturbances. 

In a new building it is possible to in-
stall an adequate and satisfactory general 
lighting system, while in the older build-
ings this is frequently impossible. I t may 
be that the wiring is inadequate or the 
structure of some of the older libraries is 
such that even with adequate wiring it 
would be impossible to do satisfactory 
remodelling of general lighting. In this 
event, second choice is a local lighting 
system in the form of table lamps. T o do 
this with the incandescent lamp produces 
excessive heat close to the worker and it 
is difficult to reduce the brightness of the 
unit using these high brightness sources 
so that the reflected glare is not irritating. 

Discussion will therefore center around 
the fluorescent type of table lamp because 
it is a line source of light of low bright-

ness and high efficiency which is readily 
adaptable to table lamp service. 

T h e problem may be divided into two 
parts, considering ( 1 ) the table itself and 
( 2 ) the lighting equipment. T h e work 
surface and the conditions of lighting 
which surround the individual are as im-
portant as is the lighting of the book or 
the notes. 

The Table Surface 

T h e table may be either of a sloping-
top or a flat-top type. General use of the 
flat-top table has led to the design of 
library table lamps with a light distribu-
tion for this type of table. Information 
from libraries where use has been made 
of the sloping-top table shows that the 
students as well as the library staff have 
found advantages which make this type 
of surface desirable. 

A t the beginning of the investigation of 
library table lamps, various types of tables 
with sloping-tops were studied. T h e 
width of the table should be forty-eight 
inches and from the reactions of a large 
number of students preference seems to 
be given to a table which has a pitch of one 
inch in seven. T h e section for the sloping-
top on the forty-eight-inch table would 
consist of a six-inch flat portion in the 
center, elevated three inches above the 
edge of the table. I n the remaining 
twenty-one inches on each side the slope 
will be three inches in twenty-one inches or 
one in seven inches. T h e one objection 
which may be raised is that pencils and 

306 COLLEGE AND RESEARCH LIBRARIES 



pens roll from the surface. In the investi-
gation it was found that the student 
quickly learned to place the pencil or pen 
in such a position that it did not roll. 

T h e table with a sloping top did not 
increase the reflected glare nor did it in-
troduce any marked difficulties into the 
problem of surface lighting. If this type 
of table becomes more generally used, the 

from any gloss. T h e table surface should 
have a reflection factor of from 20 to 
30 per cent or even higher depending upon 
the material and the problem of main-
tenance. Figure 1 gives the spectral dis-
tribution of some of the materials offered 
on the market and those below 20 per 
cent reflection factor should not be con-
sidered seriously, if the object is to obtain 

F I G U R E I . S P E C T R A L D I S T R I B U T I O N C U R V E S F O R M A T E R I A L S U S E D FOR 

L I B R A R Y T A B L E T O P S . 

design of the lamp should be such as to 
give a more uniform distribution than that 
given when using lamps designed for the 
flat-top table. W i t h a demand for such 
a lamp it is certain that the manufacturers 
will produce one meeting the specific re-
quirements introduced by a change in 
practice. 

Color of Table Surface Important 

T h e color of the table surface is also 
important. T h e finish, whether a natural 
wood or some form of composition ma-
terial, should be light in color and free 

the most desirable surface upon which to 
work. T h e reflection of the various ma-
terials shown a r e : 

Reflection F a c t o r 
No. per cent 

1. Light g r a y 28 
2. M e d i u m g r a y 20 
3. D a r k g r a y 13 
4. D a r k green 6.6 
5. Black 5-4 
6. N a t u r a l oak 30 

Number 6 is a natural oak finish in 
which the wood is filled, sanded, and 
covered with two coats of depolished 
varnish. T h i s surface gives the highest 
reflection factor of those tested and is a 
surface which may be reproduced on many 

SEPTEMBER, 1941 30 7 



library tables now in service. T h e correct 
reflection factor may be obtained at no 
extra cost at the time a periodic renovation 
is being undertaken. T h e object in hav-
ing the work surface light in color is to 
reduce the brightness contrast between 
the work surface and the light-colored 
book pages and paper in general use. 

T h e question of the length of the table 
depends entirely upon local conditions. 
Library table lamps are so designed that 
it is possible to obtain multiples of units 
to accommodate tables of any length. 
W h e r e fluorescent lamps are to be used 
the forty-eight-inch lamp, being the most 
efficient is the natural choice, therefore 
regardless of the length of the table it 
should be a multiple of forty-eight inches 
with an extra foot added to the ends. 

General Lighting in the Room 

As would be pointed out in any dis-
cussion of lighting, the illumination in the 
room and the finish of the room in gen-
eral are important if library lamps are to 
function in producing the most satisfactory 
lighting conditions for prolonged tasks of 
reading, note taking, and writing. 

T h e ceiling of the room should be light 
with a reflection factor of 75 per cent or 
more with a sidewall reflection factor of 
50 to 60 per cent. T h e general illumina-
tion in the room should be such that the 
ratio of brightness of the surroundings 
will be from 10 to 20 per cent of the 
brightness on the material which is being 
used. All equipment in the line of vision 
should be treated in a manner similar to 
the table top to lower the difference of 
brightness of objects which must be viewed 
continually or intermittently. 

O n e of the most disturbing conditions 
may be caused by windows or other large 
areas of brightness. For a short period 

of time such an area may seem comforta-
ble, but continued exposure will produce a 
direct glare which will become very 
irritating. These areas should be prop-
erly shaded or the tables should be so 
placed as to remove them from the line 
of vision. 

In good practice, in rooms where the 
natural illumination comes from one side 
of the room, the lamps located farthest 
from the windows should burn continu-
ously. T h e correct installation of circuits 
will facilitate the operation of the lighting 
system in such a manner as to produce 
a satisfactory level of illumination at all 
times with the greatest saving of electrical 
energy. T h e control can be automatic 
when photoelectrical controls are installed. 
T h e general reading rooms and reference 
rooms of a library represent one of the 
places where such control will justify the 
additional first cost. 

T h e table lamp introduces new prob-
lems in the general appearance of the 
room. T h e equipment on the table pro-
duces an appearance of bulk unless the 
dimensions are limited and where there 
is a problem of discipline in the school 
library the lamps themselves offer a screen 
which will hide the workers from the 
supervision of the attendant. 

Fluorescent Library Table Lamp 

Compactness and efficiency of the fluor-
escent lamp make it the logical type of 
source for the library service. I t is not 
free from undesirable features but for 
the specific task considered, it represents 
as close to perfection as may be attained 
today. 

One of the usual objections to the 
fluorescent installation is a hum which 
can only be diminished and not com-
pletely removed. First it is essential that 

308 COLLEGE AND RESEARCH ) L I B R A R I E S 



the auxiliary equipment be of the highest 
quality. A t this point it is foolish to 
consider price rather than quality in pur-
chasing. These units have the hum re-
duced to a minimum. T h e unit is usually 
mounted in the lamp equipment proper 
and if this is heavily constructed and the 
ballasts properly cushioned the hum will 
be of very low level. Some experi-
mental work has shown that the surest 
way to reduce the hum to a minimum and 
to be assured that it will not increase 
with the age of the equipment is to mount 
the ballast on cushioning under the table 
proper where the mass of the support is 
large and the period of normal vibration 
will not fall within the range of the hum, 
thereby eliminating the possibility of res-
onance. T h i s increases to some extent 
the wiring needed, but it places the bal-
last where it is easily accessible as well 
as making available an excellent surface 
on which the ballast may be properly 
and firmly cushioned. 

Individual Controls 

For economical operation it is desir-
able to have individual controls at the 
lamps so that when the work surface is 
not in use the lamp can be turned off 
by the individual in charge. T h e length 
of the unit will determine the number of 
local switches needed; one for each four-
foot length of table seems satisfactory. 

T h e mechanical construction of the 
lamp should be according to superior 
specifications, for a lightweight metal pro-
duces an inferior product and reflection 
surfaces depend upon the material for 
their efficiency. For light control either 
specular surfaces or lenses must be used. 
It is necessary to properly maintain the 
lamps, therefore all the parts which must 
be replaced must be readily accessible. 

Reflected Glare 
T o reduce the reflected glare from the 

work it is necessary to have some form of 
diffusing material below the lamps lo-
cated in the equipment. It has been 
found that a sanded glass with a trans-
mission of 70 per cent will reduce the 
brightness of the lamp sufficiently and at 
the same time will not lower the efficiency 
of the equipment seriously. Foot-candles 
alone should not be taken as an indication 
of the efficiency of the source for the 
quality of light obtained is equally im-
portant. 

W h e n glass covers are used, it is best 
to so design the lamp that the glass may 
be slipped into the fixture from the end, 
and for servicing of lamps and switches 
the glasses may be slipped over each other 
in the equipment proper. T h i s glass cov-
ering also eliminates the possibility of 
tampering with the lamps and switches in 
the equipment. 

A t this point it is necessary to call at-
tention to the fact that table lamps of 
the types discussed in the last part of the 
paper are for reading with the book or 
paper on the surface of the table, the 
normal condition in the school and refer-
ence library. W h e r e the lamps are to be 
used for reading with the book or paper 
on the edge of the table and tilted at a 
sharp angle, the line of lamps should be 
doubled with a single line of sources about 
one foot from the edge of the table. T h i s 
arrangement is not good for general school 
use, but would prove more satisfactory in 
the public library where there is a tend-
ency to read and not to work on assign-
ments and make notes. T h e equipment 
offered for sale today is for a surface used 
for work, not for a surface used for 
leisure reading. T o tilt the book or paper 
severely makes use of the general lighting 

SEPT EMBER, 1941 309 



200 

150 

100 

5 0 

to 0 
u 

| WORK AREA | 

^VSM 

\ 

\ 
\ 

<RM 

> 

RE} 
* 

» 

S£>> 
"-T 

REFLECTOR A 

2 4 18 

8 2 0 0 
LL. .I 

150 

100 

5 0 

FLAT TOP 
12 6 

. INCHES 
I WORK AREA 

Id 
OQ 

UJ 

s 
N 

N \ 
S \ 

\ > 
\ 

\ 
( R M 

N. 

V S M 

SLOPE TOP 
F I G U R E 2 . R E F L E C T O R S H A P E A A N D F O O T - C A N D L E D I S T R I B U T I O N C U R V E S FROM 

C E N T E R O F L A M P TO E D G E OF T A B L E . ( R M reflector only at middle of lamp, R E 
reflector only at end of lamp, S M at middle of lamp w i t h sanded glass cover, S E at 
end of lamp w i t h sanded glass cover. See T a b l e A ) . 

E Q U I P M E N T A 
Reflector 

Only 
Light 

Sanded 
Heavy 
Sanded 

Type Table Sloping Flat Sloping Flat Sloping Flat 
Mounting I 5 i " 184" 154" 154" 184" 154" 184" 
Transmission Factor (per cent) 79.0 79.0 7i-3 7i-3 
Reflected Brightness 

(candle/sq. in.) 0-35 0.24 0.32 0.23 0.22 0 . 1 9 0 . 1 9 
Table Average 

(foot-candles) 9i 90 100 78 82 81 78 
W o r k Area Average 

(foot-candles) 82 89 93 73 66 61 64 
Efficiency (per cent) 

Table T o p 50.5 50.0 55-5 43-3 45-5 45-0 43-3 
Efficiency (per cent) 

W o r k Area 22.8 24.7 25.8 20.3 18.3 16.9 17.8 
See Fig. 2 

310 COLLEGE AND RESEARCH LIBRARIES 



F I G U R E 3 . R E F L E C T O R S H A P E B A N D F O O T - C A N D L E D I S T R I B U T I O N C U R V E S FROM 

C E N T E R O F L A M P TO E D G E OF T A B L E . ( R M reflector only at middle of lamp, R E 
reflector only at end of lamp, S M at middle of lamp with sanded glass cover, SE at 
end of lamp with sanded glass cover. See T a b l e B ) . 

E Q U I P M E N T B 

Reflector Light 
Only Sanded 

Type Table Sloping Flat Sloping Flat 
Mounting i 5 i " 184" 154" 184" 
Transmission Factor (per cent) 79 79 
Reflected Brightness (candle/sq. in.) 0 . 2 4 0 . 2 1 0 . 1 9 0 . 1 9 
Table Average (foot-candles) 1 0 7 H I 79 79 
Work Area Average (foot-candles) 8 2 9 6 56 6 3 
Efficiency (per cent) Table Top 59-5 6 1 . 6 43-9 43-9 
Efficiency (per cent) Work Area 2 2 . 8 2 6 . 7 15.5 17-5 

See Fig. 3 

without gaining the advantages of the 
library table lamp. 

Figures 2 through 8 and tables from 
A to G give the specific information con-
cerning various types of library table 

lamps. T h e tables list the quantitative 
values while the figures give the shapes of 
the reflectors and the distribution of the 
illumination on the surface of both flat-
and sloping-top tables. 

I WORK AREA | 

12 
. INCHES 
I WORK AREA 

SEPTEMBER, 1941 311 



SPECULAR 

•WHITE 

F I G U R E 4 . R E F L E C T O R S H A P E C , A N I N D I R E C T E Q U I P M E N T . D I S T R I B U T I O N C U R V E S 

FROM C E N T E R OF L A M P TO E D G E OF T A B L E . ( F M middle of lamp on flat-top table, 
F E at end of lamp on flat-top table, S M at middle of lamp on sloping-top table, SE at 
end of lamp on sloping-top table. See T a b l e C ) 

E Q U I P M E N T C 

Type Table Sloping Flat 
Mounting 13" 1 3 " 1 6 " 
Reflected Brightness (candle/sq. in.) 0 . 1 8 0 . 1 3 0 . 1 4 
Table Average (foot-candles) 34 36 33 
Work Area Average (foot-candles) 34 35 37 
Efficiency (per cent) Table Top 1 8 . 9 2 0 . 0 18.3 
Efficiency (per cent) Work Area 9-4 9-7 10.3 

See Fig. 4 

Comparing Performance 
Since there have never been specifica-

tions established for the testing of this 
type of lamp it is necessary to establish 
some method for comparing the perform-
ance of the equipment. Measurements of 
illumination were made with a brightness 
meter and a magnesium oxide disc; the 
brightness measurements were made with 
the same brightness meter. Observations 
were taken on the surface of the table at 
six-inch intervals. Averages were com-
puted for two conditions: 

1. T h e table average represents the 
average illumination over the surface of 
a forty-eight-inch table to a line twelve 
inches beyond the end of the fluorescent 
lamps. 

2. T h e work area average represents 
more accurately the effective illumination 
of the lamp, for it represents the area 
actually used by the student. T h i s area 
is a strip twelve inches wide measured 
three inches from the f r o n t edge of the 
table to a line fifteen inches from the 
f r o n t edge of the table, at the ends to 

312 COLLEGE AND RESEARCH ) L I B R A R I E S 



REFLECTOR £) 

WORK A R E A 

SLOPE TOP 

F I G U R E 5 . R E F L E C T O R S H A P E D A N D F O O T - C A N D L E D I S T R I B U T I O N C U R V E S FROM 

T H E C E N T E R OF L A M P TO E D G E O F T A B L E . ( R M reflector only at middle of lamp, 
R E reflector only at end of lamp, R G M at middle of lamp with ribbed glass cover, 
R G E at end of lamp with ribbed glass cover. See T a b l e D ) 

E Q U I P M E N T D 

Reflector 50 per cent Clear 50 per cent Ribbed 70 per cent Pebbled 
Only 50 per cent Sanded 50 per cent Sanded 30 per cent Sanded 

Type Table Sloping Flat Sloping Flat Sloping Flat Sloping Flat 
Mounting 1 4 i " 144" T tX" 142 144" 144" 144" 144" T ,X" 142 
Transmission Factor 

(per cent) 
(a) Sanded 7 0 . 4 7 0 . 4 6 9 . 6 6 9 . 6 7 2 . 1 7 2 . 1 
(b) Other Surface 8 8 . 9 8 8 . 9 8 9 . 8 8 9 . 8 8 9 . 2 8 9 . 2 

Reflected Brightness 
(candles/sq. in.) 0.13 0 . 1 4 
(a) Sanded 0.14 0.12 0.075 . 0 6 5 0.095 0 . 1 2 
(b) Other Surface 0 . 1 2 0.11 0 . 0 8 .075 0 . 0 9 0 . 1 3 

Table Average 
(foot-candles) 4 8 52 4 2 4 2 41 44 43 4i 

Work Area Average 
(foot-candles) 38 47 31 32 30 35 33 2 9 

Efficiency (per cent) 
Table Top 2 6 . 6 2 8 . 9 23-3 23-3 2 2 . 8 2 4 . 4 23-9 2 2 . 8 

Efficiency (per cent) 
Work Area 10.5 13-0 8 . 6 8-9 8.3 9-7 9 . 2 8.1 

See Fig. 5 

SEPTEMBER, 1941 313 



F I G U R E 6 . R E F L E C T O R S H A P E E , A L E N S C O N T R O L L E D L I G H T I N G E Q U I P M E N T . D I S -

T R I B U T I O N C U R V E S FROM T H E C E N T E R O F L A M P TO E D G E O F T A B L E . ( F M at middle 
of lamp on a flat-top table, F E at end of lamp on a flat-top table, S M at middle of lamp 
on a sloping-top table, SE at end of lamp on a sloping-top table. See T a b l e E ) . 

E Q U I P M E N T E 

Type of Table Sloping Flat 
Mounting i 5 r 20" 
Reflected Brightness (candles/sq. in.) .055 •055 
Table Average (foot-candles) 32 27 
Work Area Average (foot-candles) 29 25 
Efficiency (per cent) Table Top 17.8 15-0 
Efficiency (per cent) Work Area 8.i 6 . 9 

See Fig. 6 

a line twelve inches beyond the end of 
the fluorescent lamp. 

T h e efficiency of the lamp for the two 
areas is computed on the lumen output 
of a daylight fluorescent lamp. T h e ratio 
of the total lumens on the area to the 
lumens generated by the lamps has been 
defined as the efficiency of performance of 

the library lamp. Daylight fluorescent 
lamps were used in the test. 

T h e lamps were operated one hundred 
hours before the tests were made. T h e 
daylight lamp represents the low values 
of foot-candles and was used because of a 
tendency to specify this color temperature. 
Except where it is desired to color match 

314 COLLEGE AND RESEARCH ) L I B R A R I E S 



SPECULAR 

50 

4 0 
</> UJ 

§ 3 0 < 
0 
1 

§20 
u_ 

WORK AREA 

10 

R E F L E C T O R F 

s / . R M 

\ 

SOM \ \ 
R E l 

s V S M 

X \ 
V S M 

X \ 
\ 

V N 

V 

\ N 
V 

2 4 18 
FLAT TOP 

12 
INCHES 

F I G U R E 7 . R E F L E C T O R S H A P E A N D F O O T - C A N D L E D I S T R I B U T I O N C U R V E S FROM 

C E N T E R OF L A M P TO EDGE OF T A B L E . ( R M reflector only at m i d d l e of lamp, R E 
reflector only at end of lamp, S M at m i d d l e of l a m p w i t h sanded glass cover, S E at 

end of l a m p w i t h sanded glass cover, S O M at m i d d l e of l a m p w i t h sanded flashed 

opal glass cover, S O E at end of l a m p w i t h sanded flashed opal glass cover. See T a b l e F ) 

E Q U I P M E N T F 

T y p e of T a b l e 

M o u n t i n g 
T r a n s m i s s i o n F a c t o r ( p e r c e n t ) 
R e f l e c t e d B r i g h t n e s s ( c a n d l e s / s q . in.) 
T a b l e A v e r a g e ( f o o t - c a n d l e s ) 
W o r k A r e a A v e r a g e ( f o o t - c a n d l e s ) 
Efficiency ( p e r c e n t ) T a b l e T o p 
Efficiency ( p e r c e n t ) W o r k A r e a 

F l a t 

1 8 4 " 
27.1 
0.041 
20 

15 
22.2 
8.3 

See F i g . 7 

n a t u r a l l i g h t e n t e r i n g the w i n d o w s it is 

more economical to use the w h i t e l i g h t 

w h i c h supplies a p p r o x i m a t e l y 23 per cent 

more lumens f o r the same w a t t a g e . A l l 

research indicates that there is no benefit 

to seeing by using the d a y l i g h t lamps. 

T h e equipments A , B , C , D , and E 
are t w o - l a m p equipment w h i l e F and G 

are single-lamp types. T h e first are the 

most expensive both as to first cost and 

operation w h i l e the last t w o have a l o w e r 

first cost and o p e r a t i n g cost. W h e r e the 

lamps are contained in a c o m m o n re-

flector there is some reduction in the 

stroboscopic effect, but the l i g h t m i x t u r e 

f r o m the t w o - l a m p combination is not 

enough t o g i v e the same e f f e c t as ob-

tained w i t h ceiling equipment. T h e 

single-lamp types are distinctly strobo-

scopic, but in an installation of this type 

w h i c h w a s under observation there w e r e 

no complaints on this score. 

SEPTEMBER, 1941 315 



WORK AREA 

REFLECTOR G 

SLOPE TOP 

F I G U R E 8 . R E F L E C T O R S H A P E G A N D F O O T - C A N D L E D I S T R I B U T I O N C U R V E S F R O M 

CENTER OF L A M P TO EDGE OF T A B L E . ( R M reflector only at m i d d l e of l a m p , R E 
reflector only at end of lamp, O G M at m i d d l e of l a m p w i t h flashed opal glass cover, 
O G E at end of l a m p w i t h flashed opal glass cover. See T a b l e G ) 

FLAT TOP 
Ld 

18 12 6 0 £ 
INCHES 3 

| WORK AREA I 

E Q U I P M E N T G 

R e f l e c t o r O p a l R e f l e c t o r O p a l 
O n l y G l a s s O n l y G l a s s 

T y p e T a b l e Sloping F l a t Sloping F l a t Sloping Sloping 

M o u n t i n g f r o m L o w P o i n t T a b l e i 6 " i 6 " 1 6 " 1 6 " 1 3 " 1 3 " 
T r a n s , ( p e r c e n t ) 49-5 49-5 49-5 49-5 
R e f l e c t e d B r i g h t n e s s 1.52 1.78 0.12 0.12 0.12 0.16 
T a b l e A v e r a g e 36 40 33 35 4 i 39 
W o r k A v e r a g e 37 42 27 29 40 26 
T a b l e T o p Efficiency ( p e r c e n t ) 3 2 . 4 37 29-7 3 i - 5 36.9 35-i 
W o r k A r e a Efficiency ( p e r c e n t ) 20.6 23.3 15.0 16.1 22.2 14.4 

See F i g . 8 

S o m e of the units w i t h t w o lamps g i v e 

v e r y m u c h higher surface i l l u m i n a t i o n but 

are no more efficient than the better of 

the single l a m p units. I t is questionable 

if at the present stage of development of 

this type of l i g h t i n g it is j u s t i f i a b l e to 

install equipment p r o d u c i n g e i g h t y to one 

h u n d r e d foot-candles on the s u r f a c e of 

the table by means of local l i g h t i n g . 

E v e n the most ardent advocates of higher 

l e v e l s of i l l u m i n a t i o n w o u l d be satisfied 

w i t h f i f t y foot-candles as a high l i m i t 

w h i l e the recommendations by the I l l u -

m i n a t i n g E n g i n e e r i n g Society f o r school 

buildings recommend a m i n i m u m of f i f t e e n 

foot-candles. A t the higher i l l u m i n a t i o n 

316 COLLEGE AND RESEARCH LIBRARIES 



given it would be necessary to increase 
the general room illumination found in 
many libraries considerably to attain the 
proper surrounding illumination. 

T h e material in the tables and figures 
has been arranged to give information con-
cerning typical lamps being offered for 
the service being discussed. It has been 
arranged and analyzed for the considera-
tion of those who are studying the use 
of fluorescent lamps for library tables. 
T h e curves on the figures show the illum-
ination distribution at the center of the 
forty-eight-inch lamp and at the end of 
the lamp with reflector only and with 
diffusing material over the bottom. T h e 
analysis, in those instances where it is pos-
sible, considers both the flat-top and the 
sloping-top table. T h e reader can draw 
his own conclusions concerning the merits 
of the various lamps. I t is necessary 
to reduce the direct and reflected bright-
ness to as low a value as possible. W h e r e 
no record is made of direct glare, it will 
be understood that no part of the re-
flector or lamp was in the line of vision. 
T h e reflected glare represents the bright-
est portion of a glazed piece of paper 
(83 per cent reflection) in the normal 
study position. 

Summary 

A study of the requirements of the li-
brary table lamp shows that a single row 
of fluorescent lamps in a suitable equip-
ment properly designed is capable of 
supplying the necessary illumination for 
the work area. T h e lamp should be 
mounted with the lowest portion of the 
reflector sixteen inches above the lowest 
edge of the table whether the table has 

a flat or a sloping top. For the sloping 
top this is thirteen inches above the six-
inch center strip. 

T o reduce the reflected glare the equip-
ment should have some form of diffusing 
media below the fluorescent lamp and this 
can be of relatively high transmission. 

T h e surroundings should be illuminated 
and treated according to the recommenda-
tions for any general lighting system. T h e 
work area and the equipment should be 
of a lighter color than is the general 
practice in the library at present. T h e 
equipment should be of good material and 
the workmanship produce a sturdy and 
durable table lamp. Provisions for serv-
icing should be a part of the specification. 

I t would be desirable to have a qualified 
committee to study the problem of equip-
ment and specifications for library table 
lamps establishing some standard require-
ments similar to those that have gov-
erned the I.E.S. specified lamp. T h e 
one factor which is hindering the adoption 
of some type of lamp of this sort is the 
confusion concerning the merits of the 
equipment being offered for sale. 

T h e lack of a reliable, approved equip-
ment or a clear-cut specification which may 
be subjected to standard tests, is retarding 
the installation of many local lighting 
systems in libraries and thereby many are 
suffering from a lack of adequate lighting, 
not because the library administration is 
not conscious of the need for this lighting, 
but because the administration is con-
fused by the many claims and counter-
claims made by sales organizations and 
has no information sponsored by a disin-
terested agency concerning the merits and 
requirements for a good lamp. 

SEPTEMBER, 1941 317