118 THE JOURNAL OF THE SOCIETY OF DYERS AND COLOURISTS. bug. 2k18S’i.

SOME OBSERVATIONS I N COLOUR- MATCHING.

COMMUNICATION FROM HERBERT CROSSLEY.

IT .will be in the recollection of those who were present when Messrs. Emmott and Ackroyd gave their lecture on “ Colour-matching ” that I showed some samples of dyed worsted which matched each other in daylight, but when viewed in the gaslight exhibited some very peculiar effects, and when looked a t under the electric or magnesium light did not match.

I was requested by several of the members to allow these patterns to be published with the Journal, so that all who were interested might have an opportunity of notinv the different effects under different auspices at t te i r own leisure.

I, therefore, though late in the day, now have pleasure in conlplying with the request, and I trust that they may prove of some use to any of the members who are necessarily placed in the position of not having sufficient daylight to carry out and complete their work.

Three of the colours are a fair match in ordinary daylight ; one sample of each colour has been dyed with different colouring matter. I give as under the different kinds of colour used in each case :-

Archil Liquor

Fast Yellow So. 1. Ited Brown . . . . . . . . . Extract Indigo

L Scarlet 21t ....... ,. 2 . ,, ,, . . . . . . . . . .! Extract Indigo ( Past Yellow j Past Yellow

i Archil Liquor Acid Green

.............. Fast Yellow Orange Past Yellow

Archil Liquor lj‘ast Yellow

,, 3. Green . . . . . . . . . . . . . . { Extract Indigo

1, 4. 1,

,, 5. Olive 1iron.n . . . . . . . . Extract Tndigo

.x ract Indigo

i ,, 6. ,, ,, ......... L t ) Orange

It will be noted in Nos. 1 and 5 the red-colourin6 matter was archil liquor, whilst in Nos. 2 and f scarlet 2lt and orange was used ; in gaslight thc difference is most marked, the patterns dyed wit1 archil liquor showing quite a rosy or with a brick red effect. Nos. 3 and 4 also show a strange contras, when compared by gaslight, and although archi liquor is used in the one and orange in the other, . am not prepared to say that the great contrast ha; been caused by the use of, necessarily in this case, s( small a portion of red colour. The difference ii owing, I think, to the use of extract of Indigo in on1 case as a. ainst acid green in the other. Thesi patterns i lkstrate some of the difficulties with whicl colour-matchers and dyers have to contend.

Having a colour to dye and match, the dyer at onc, employs the different dyes with which he is mm accustomed to work, and which he thinks the cheapes or best able to keep their co!our. H e is seldpniinformec for what urpose the fabric to be dyed is intended i t may gave to be used with similar fabric i every particular, dyed by another dyer and therefor used in all sorts of light to ether, or it may be batch to match a lot that ha2 been dyed some tim

-~ _ _ - --- efore, probablyin quite a different manner. I t herefore becomes almost the duty of the dyer not nly to know how to dye and match a certain colour hat may be submitted, but he should also be able o ascertain how the colour he has to match has been yed, and thus to obtain a uniform result. Fresh patterns Nos. 7 and 8 are given to illustrate

uite a different effect in daylight, the colours are istinctly buff and salmon pink, whilst when seen nder the influence of gaslight seem to be of the same hade. They are dyed as under :-

Cochineal Flavine ............ No. 7 . Buff {

,) 8. ,, ............{Orange Scarlet 21t

From these remarks and illustrations I trust I have ,een able to show some of the difficulties with which olour-matchers have to contend sometimes for two lr three months of the year, and I inlist confess I Iften wonder really how well the colours turn up, nd how few have to be returned for bad matching. ill dyers anxiously look forward to the time when ome artificial light will be introduced which will nake them independent in a measure of daylight. Chemagnesiuni and theelectric lights are great strides n this direction, but are as yet farfrom perfect ;but I lave no doubt that by bringing practical electric- ight engineers and practical colourists together blight will be obtained in the near future that will ,olve the difficulty--and if so, thrn the lecture of kfessrs. Emmott and Ackroyd and these remarks will lot have been of no avail.

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I‘HE FIXATION O F CHROMIUM BY T H E WOOL-FIBRE.

COMMUNICATION FROM P. KAY AND E. BASTOW.

SINCE the introduction of bichromate of potash as L mordant for wool about the year 1840,comparatively ittle has been done in order to ascertain the amount i f chromium actually fixed by the fibre or the nature if the chemical changes which take place during the irdinary process of mordanting. The only important publications on this subject which we have been able :o find are those of J. J. Hummel (“The Dying of I’extile Fabrics,” pp. 208 and 326), J. B. Wilkinson ‘see this Journal, vol. i. p. 36) and R. Lloyd Whiteley ~Jou~. SOC. CJiem. Ind. Feb. 1887). Since, however, the inferences are not in any case based on strictly pant i ta t ive estimations, we have, a t the suggestion m d under the guidance of Ih. E. Knecht, carried out the following series of experiments, which we hope will throw a somewhat clearer light on the subject.

The material used in these experiments was R medium quality of flannel scoured and finished and &,for convenience sake into pieces of 10grms. each. It contained 0.60 per cent. of ash.

CC.-AMOUNT OF CHROXIUM FIXED. I n the first experiment six pieces were mcrt1;inted

for one hour a t looo C. in solutions of bichrollliLte of potash made up in each case t o 1OOOcc. The follow- ing proportions of mordant were used :-

After mordanting, the ieces were taken out, and excess of liquid absorbei squeezed hack as far as possible into the mordant solution. The were then well washed in cold water and dried. $he amount of chromium fixed was determined in each case