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41 per cent a n d 65 per cent relative humidities is I O per cent, while a n increase i n humidity from 65 per cent t o 8 2 per cent caused a reduction in t h e breaking length of 27.2 per cent, a total variation of over 3 7 per cent. For Series I V , No. I kraft, t h e variation i n breaking length for t h e humidity change from 44 per cent t o 64 per cent was 6.4 per cent, while with a n increase i n humidity from 64 per cent t o 8 2 per cent t h e drop in breaking length was 19.3 per cent, a total variation of 2 j . 7 per cent. 111-The stretch of t h e paper increases with increase i n relative humidity, t h e variation being rather more regular t h a n with points per pound a n d breaking length. F o r t h e groundwood-sulfite mixture, Series I, t h e stretch increased 17.0 per cent, with increase i n relative humidity from 41 per cent t o 65 per cent, a n d 3 1 per cent with increase i n humidity from 65 per cent t o 8 2 per cent. For t h e Series I V , KO. I kraft, t h e stretch increased 20.4 per cent with increase i n relative humidi t y from 44 per cent t o 64 per cent, a n d 18.7 per cent with increase i n humidity from 64 per cent t o 8 2 per cent. IT‘-The folding properties seem t o be affected t o a greater degree t h a n a n y other property. For t h e groundwood-sulfite mixture a n d t h e all sulfite papers, t h e resistance t o folding increased tremendously between 5 5 a n d 7 7 per cent relative humidity, a further increase i n t h e moisture content, however, causing t h e folding strength t o break sharply. With t h e kraft papers, t h e folding strength increased with t h e increase in humidity a n d a t t h e most s a t u r a t e d condition used, v i z . , 8 2 per cent, t h e papers showed far greater folding strength t h a n at 77 per cent. For t h e groundwood-sulfite paper, Series I, t h e number of folds increased I j 3 per cent with a humidity increase from 41 per cent t o 7 7 per cent. Above 7 7 per cent relative humidity t h e folding strength decreased, showing t h a t t h e per cent of relative humidity giving greatest folding strength h a d been passed. For Series IV, 30-lb. paper, t h e number of folds increased from 3 4 8 a t 44 per cent relative humidity t o 1980 folds at 8 2 per cent humidity, a n increase of 470 per cent, while t h e 60-lb. paper showed a n increase of 588 per cent i n t h e folding strength i n varying t h e relative humidity from 44 t o 82 per cent. T h e results obtained are sufficient t o show t h a t when paper is bought a n d sold on strength specifications, more uniform results would be obtained if t h e relative humidity a t t h e time of testing were specified. FOREST PRODUCTS LABORATORY MADISON, WISCONSIN
FURTHER STUDIES ON A NUMERICAL EXPRESSION FOR COLOR AS GIVEN BY THE IVES TINT PHOTOMETER By OTTO KRESSAND G. C. MCNAUGHTON Received January 22, 1917
I n a previous paper b y t h e authors’ we described t h e results of some experiments i n a t t e m p t i n g t o determine a numerical expression for color of paper as given b y t h e Ives T i n t Photometer. These experiments were made, (I) t o determine if color indica1
Paper, August 2, 1916, and TIIISJOURNAL, 8 (1916). 711.
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tions as shown b y t h e Ives T i n t Photometer could be employed as a means of measuring t h e progress of beating, a n d ( 2 ) t o observe t h e relation between t h e numerical expression for d e p t h of color as read b y t h e instrument, as compared with t h e grading for d e p t h of color as observed b y visual inspection. As reported in t h e previous paper we found it was possible t o give a numerical expression for d e p t h of color of papers comparable t o visual grading where t h e variations were produced b y either varying t h e a m o u n t of color or b y holding t h e a m o u n t of dyestuff constant a n d varying t h e depth of color b y variation i n t h e hydration of t h e stock. T h e m a t t e r of scientifically a n d accurately recording color both as t o hue a n d intensity is one of especial interest t o those interested i n paper research. A numerical expression for color is of value for purposes of scientific record a n d description, a n d for comparison a n d classification of papers a n d paper stocks. T h e best prepared papers m a y change i n shade in a comparatively short time, due t o changes of t h e paper stock itself or t h e fugitive character of t h e dyestuff. F u r t h e r experiments were made i n order (I) t o determine whether a n y shade matched visually i n b o t h hue a n d intensity with a different combination of dyestuffs would give t h e same t i n t photometer reading, (2) t o s t u d y t h e darkening action caused b y calendering of paper a n d whether such progressive darkening action could be numerically recorded, a n d (3) t o s t u d y if there is a definite relation between t h e readings of t h e t i n t photometer a n d t h e glarimeter for successive increases in darkness a n d finish as produced b y progressive calendering. For description of t h e Ives T i n t Photometer reference is made t o our previous paper. Through t h e courtesy of t h e Badische Company, New York City, some paper dyeings made on a furnish of 80 per cent groundwood a n d 2 0 per cent unbleached sulfite stock a n d sized with rosin size were obtained. A paper which will be designated a “brown shade” using per 1000 pounds of stock, Vesuvine BPX 4 lbs.
Auramine Conc. 12 02.
Safranine ‘ I ‘ extra Conc. 4 02.
was accurately matched both for shade a n d d e p t h of color b y a dyed paper using per 1000 pounds of t h e same stock. Auramine Conc. 3 Ibs. 21/2 oz.
Safranine T extra Conc. 2 Ibs. 1 1 / i 02.
Victoria Green B F 11/4
02.
a n d this dyeing will be designated a s “brown match.” These two dyeings matched well under both n a t u r a l a n d artificial light a n d gave t h e following readings under t h e Ives T i n t Photometer, t h e results being t h e average of j readings: TINTPHOTOMETER READINGS
Red PARTS: 73.7 Brown shade, .. , , , , Brown match.. .. . . , . . . . 73 8
... . .
Green 37.1 37.2
Blue 31.0 30.9
Black 158.2 158.1
X “blue shade” was prepared using per 1000 pounds paper stock, consisting of 80 per cent groundwood a n d 2 0 per cent unbleached sulfite, hlethyl Violet N 3 lbs. 1010 02.
Victoria Blue B Conc. 1 lb. l O I / z 02.
This was matched with a “blue match” using per pounds of t h e same stock,
1000
II:.:-.. 191;
T M E J O l - R S . 4 L O F I S D 1 7 S T R I . 1 L A S D E.VGIA*EERISG C H E V I S T K P Xethylene Blue B C S I lb. 5112 02.
I f e t h y l Violet S 3 lbs. 101/2 02.
Tlitse two dyeings a r s fair matches under natural light whereas under artificial light t h e combination with T‘ictoria Blue is. of course, decidedly redder. O n comparing these dyed samples under t h e Ives Tint Photometer t h e follon-ing aT-erage readings m-ere o b7 ;i ine d : Red PARTS: i3lue shade . . . . . . . . . . . . .25.9 Blue m a t c h . . . . . . . . . . . , . 27.1
TINT PHOTOMETER READISGS Black Green Blue 197.9 27.3 49.5 2i.5 17.2 197.3
The readings as given for both t h e brown and t h e blue matches check Tvithin t h e allowable experimental error showing t h a t matches made with different comA ~ o r s rASD KIND Xo.
Sample DESCRIPTION Satural
Brown 5hade Brorrn match
Blue shade Blue match
OF
DYE USED
of Safranine T extra Conc. (Samples S o s . I , z b , ga, and 7 ) are shovin in plotted form. The curves are typical of all t h e dyeings examined, in so far as t h e y shon- the increase in parts black a n d t h e decrease of t h e parts red. blue, and green produced by successive calendering. T h e three sets of curl-es marked parts black, red, blue, a n d green show t h e t i n t photometer readings of t h e dyed samples with practically no finish, with a n intermediate finish and with a high finish. In order t o measure t h e per cent glare of the samples use v-as made of t h e glarimeter mrhich was invented b y Prof. Ingersoll a t t h e Forest Products Laboratory. T h e per cent glare for t h e three degrees of finish of TIKTPHOTOXETER READINGS
7-
(1) No Finish Red Green Blue Black
Sone 4 lbs. Vesuvine B P X 4 oz. Safranine T extra Conc. 12 oz. Auramine Conc. Mixture of 2a, b and c Mixture of 3a, b and c Z lbs. 11 2 oz. Safranine T extra Conc. 3 I b s . 21 ‘2 oz. Auramine Conc. 1 1 , oz. Victoria Green B. F. 3 lbs. 101/2 02. Methyl Violet X. 1 Ib. lo]:? oz. Victoria Blue B Conc. Mixture of 4a and 4b RIixture of 5 a and 5b 1 Ib. 5112 02. Methylene Blue B G S 5 lbs. Vesuvine B P X 5 lbs. Safranine T extra Conc 5 Ibs Auramine Conc. 5 Ibs. Methylene Blue B G N 5 lbs. Victoria Green B F 5 lbs Victoria Blue B Conc. 5 lbs. Methyl Violet X
33 8 70.7 79 3 84.6 24 6 23.8 24.4 34.5
61.8 35.2 26.1 75.5 46.6 46.3 35.2 2.5 I
64.3 28.8 36.3 32.2 54.4 46.2 54.3 45 3
hin:,Tions of dyestuffs, if t h e y match visually, will gil-e comparable readings with t h e Ives T i n t Photometer. The blue shade and blue match do not check as well as t h e brown dyeings either visually or under t h e tint photometer. Individual dyeings were made on t h e same stock and with t h e same proportion of dyestufis as were used in t h e brown a n d blue dyeings in t h e hope t h a t some relation could be discovered between t h e t i n t photometer readings of t h e component colors and t h e mixture. This we have not been able t o do b u t t h e tint photometer readings on these various dyed samples are given in t h e above table, and may enable some reader t o discover a relation which mill hold consistently for different colors I t is common knowledge in t h e paper mill t h a t calendering arid supercalendering will darken t h e paper. Some experiments were made t o determine n-hether t h e progressive darkening of either dyed or undyed paper as produced b y calendering could be observed and numerically recorded b y means of t h e t i n t photometer. The sample papers, prepared in identical manner wit>. little or no finish, Il-ere successively calendered t o give 7-arious degrees of finish; t h e colors were read b>- The tint photometer a n d t h e per cent glare determined by t h e Ingersoll glarimeter after each calendering. Coniplete t i n t photometer a n d per cent glare readings are given in t h e table for conditions of ( I ) no finish: ( 2 ) low finish, and (3) high finish. We h a r e no supercalender or plater a t t h e laboratory, a n d t h e various finishes were obtained on t h e samples studied through t h e courtesy of the Hammermill Paper Company, Erie, Pennsylvania. D a t a f r o m t h e t i n t photometer a n d glarimeter readings made on t h e sheets dyed with various strengths --
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140.1 165:3 158.3 107.7 174.4 183.7 186.1 195.0
(2) Low Finish Red Green Blue Black 83.2 74.5 68.9 73.4 71.5 37.5 31.1 159.9 83.1 55.0 61.5 100.4 ,9.9 75.2 47.3 97.6 71.3 37.1 30.5 161.1 71.6 36.1 30.1 162.2 79.9 32.4 44.5 143.2 81.0 72.9 35.4 110.7 60.2 71.6 66.8 101 4 36.0 26.9 45.5 191.6 30.1 44.4 58.7 166.8 27.1 26.2 46.3 200.4 26.6 27.2 44.8 201.4 33.2 69.3 77.1 82.8 24.3 23.3 24.0 34.1
60.6 35.0 26.0 72.9 44.5 45.1 35.2 25.4
62.2 28.8 35.6 32.1 51.7 44.9 51.4 45.0
144.0 1669 161.3 112.2 179.5 186.7 189.4 195.5
7
(3) High Finish Red Green Blue Black 80.2 72.6 65.3 81.9 68.8 35.6 30.1 165.5 80.2 51.3 58.5 110.0 78.1 73.0 46.5 102.4 68.7 34.1 28.8 168.4 68.5 35.0 28.9 167.6 77.3 30.9 41.8 150.0 78.1 71.6 34.9 115.4 57.6 69.3 64.0 109.1 34.4 25.8 43.8 196.0 28.8 42.2 55.5 173.5 26.1 25.0 42.0 206.9 25.1 25.0 42.5 207.4 31.0 67.1 71.7 80.7 22.9 22.4 22.3 31.7
56.5 32.8 24.5 69.9 42.2 41.8 32.0 23.2
59.1 27.3 33.2 33.1 49.5 41.5 49.6 42.0
GLARE READINGS (Per cent) :I) (2) (3) 18.8 38.7 51.4 27.7 46.0 6 5 . 8 22.5 41.1 6 2 . 0 19.2 37.6 5 9 . 5 26.0 46.3 66.2 25.0 47.4 68.1 27.0 47.7 65.6 20.3 40.0 58.2 19.8 43.5 63.4 5 2 7 11.2 82.4 41.6 5 9 2 73.4 59.9 75.3 8 5 . 0 59.7 75.4 85.8
153.4 172.8 170.6 116.3 185.4 194.3 196.1 203.1
30.2 26.5 25.3 20.0 33.1 46.4 46.6 57.6
48.1 46.9 51.0 39.7 62.9 65.8 66.7 74.0
66.4 68.1 68.2 52.7 77.0 79.0 80.2 86.2
t h e various samples examined are given in t h e preceding table and are shown graphically a t t h e t o p of t h e accompanying figure. Ibrief description of t h e general principles on which t h e use of t h e glarimeter is based. m a y be of interest; for a full description t h e reader is referred t o t h e original article describing the instrument.’ Light reflected from a sheet of paper may be considered as belonging t o one of t w o general types. First there is diffusely reflected light which means t h a t t h e light is reflected uniformly in all directions. X m a t t e surfaced paper diffusely reflects t h e bulk of t h e light falling on i t a n d m a y be considered as a typical example of this case. Secondly, p a r t of t h e light may be “specularly” reflected, which is t h e case of all light where t h e angle of incidence equals t h e angle of reflection. T h e bulk of t h e light reflected from a highly supercalendered paper may be considered as being “specularly” reflected. Practically, light reflected even from t h e dullest m a t t e finished paper is a mixture of diffusely a n d “specularly” reflected light. T h e “specularly” reflected light which is characterized b y being plane polarized causes t h e effect which is commonly known as “glare” and t h e glarimeter measures t h e percentage glare b y determining t h e percentage of “specularly” reflected light in comparison with t h e total reflected light. All papers m-ill, of course. show a certain percentage of glare, b u t m-ith increase in finish, t h e percentage glare increases. Further, all colored papers will give a higher per cent glare reading t h a n white papers of t h e same finish, as t h e actual amount of “specularly” 1 Elecfrical W o r l d hIay 15, 1914.
March 21, 1914, W o r l d ’ s Paper
T r a d e Revrcu.
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reflected light is unaffected b y t h e d e p t h of color of t h e paper, while t h e amount of diffusely reflected light is diminished, depending on t h e depth of t h e shade of t h e paper. T h e increase i n per cent glare caused b y calendering is shown b y t h e typical glare curves, as plotted i n t h e figure for dyeings made with rarious amounts of Safranine T extra Conc., on a furnish of 80 per cent groundwood a n d 2 0 per cent unbleached sulfite. T h e per cent glare of t h e blank made f r o m t h e same furnish as t h e dyed samp,les increased from 18.8 t o 38.7 t o 51.4 per cent with t h e successive calenderings. T h e effect of t h e color in increasing t h e per cent glare reading b y causing absorption of some of t h e light is evid e n t from a s t u d y of t h e curve.
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reflected. With t h e same finish b u t with increase in color, t h i s causes a n a p p a r e n t increase in per cent glare. With t h e present design of t h e glarimeter, uniform lighting conditions are secured b y a n incandescent light within t h e light-proof interior of t h e instrument, while lighting conditions for t h e t i n t photometer are secured from daylight. I n trying t o check relations between t h e t w o instruments, t h e color screens of t h e t i n t photometer were later attached t o t h e objective of t h e glarimeter while readings were being taken b u t t h e results secured were very erratic. T h u s while t h e glarimeter might be found of value in determining t h e finish of.white papers, in t h e light of our d a t a i t could not be recommended for colored papers of differe n t hues a n d intensities. FORESTPRODUCTS LABORATORY MADISON, WISCONSIN
THE CHEMISTRY OF WOOD DECAY PAPER I-INTRODUCTORY BY ROBERTEVSTAPIEPP ROSEAND MARTINWILLIAM LISSE~ Received A-ovember 2 7 , 1916
LBIIOFDYE PER IO00 LBS.OfDRY STOCK. We h a v e shown t h a t i t is possible t o give a numerical expression for both shade a n d d e p t h of color b y means of t h e t i n t photometer a n d t h a t t w o dyeings which match visually, will, within t h e allowable experimental error, match under t h e I v e s T i n t Photometer eventhough t h e t w o matches were dyed with different dyestuffs. F o r white sheets i t is possible t o follow t h e progress of calendering b o t h b y t h e t i n t photometer i n recording t h e increase i n parts black of t h e paper or b y t h e decrease i n parts red, blue, or green, a n d b y t h e glarimeter i n recording t h e increase i n per cent glare. For colored papers t h e t i n t photometer will record t h e increase i n p a r t s black for successive production of finish b y calendering, b u t t h e per cent glare will increase, not only due t o t h e finish of t h e paper itself, b u t also due t o t h e fact t h a t with darkening of t h e paper t h e a m o u n t of diffusely reflected light is decreased without changing t h e a m o u n t of light “specularly”
During t h e decay of wood t h e composition of t h e material obviously undergoes profound alteration. By slow changes t h e structure of t h e wood is destroyed, t h e macroscopic changes being accompanied b y a corresponding chemical disintegration. T h e highly complex compounds originally present pass into others of increasing simplicity until a t last ail passes i n t o carbon dioxide, water, perhaps also hydrogen a n d methane. Between wood a n d its ultimate dissolution products must lie a whole range of intermediate substances. T h e chemistry of t h e process has received b u t scant attention, though i t should prove of interest, as a scientific s t u d y , a n d as a prerequisite t o discovering possible uses for a waste product occurring i n great q u a n t i t y . T h e subject has been merely touched upon in t h e work of Omelianski.2 while t h e efforts made t o determine t h e n a t u r e of humus a n d i t s components bear only distantly upon t h e question of wood decay, although t h e results obtained should prove valuable i n determining t h e n a t u r e of t h e substances i n very rotten wood.3 T h e very nearest approach t o t h e subject has been made b y Schreiner a n d Sullivan,4 who have identified some products obtained from rotten wood a n d peat. It is clearly no easy t a s k t o determine t h e chemical changes undergone during t h e disintegration of wood under natural conditions; t h e transition of t h e material is a slow one unsuited t o laboratory s t u d y ; t h e accompanying conditions vary very greatly, a n d t h e products formed are largely lost as gases or as water-soluble compounds. Moreover, inasmuch as decay is due t o t h e activity of lower vegetative forms, t h e n a t u r e of t h e bacteria, fungus or fungi responsible will largely modify t h e outcome. 1 Used by hl. W. Lisse in part fulfillment of the requirements for the h1.S. degree in the University of Washington. 2 Compt. vend., 121 (1895), 653; 125, 970, 1131; Archiv Scienc hzoloq, 7, 411; 9 , No. 3 ; Centv. Bakf., 8 (111, 193; 11, 370 and 703. a Compare Czapek, “Die Biochemie der Pflanzen,” Vol. I, pp. 226-229. 4Sullivan, THISJOURNAL, 6 (1914), 919, and 8, 1027: 0. Schreiner and E. C. Shorey, U. S. Dept. Agr., Bureau of Soils. Bull. 74, 1914; Sullivan, Science, 38 (1913), 678.
