t very diluted eosine solutions, 1 to 20,000, acted as
a yellow sensitizer.

After washing, the plates have to be rinsed and dried--colored plates, as
long as they remain moist, being less sensitive than dry ones, and very
seldom the reverse.

This bathing of the ready made plates may give good results, but pure and
faultless plates are very seldom obtained, wherefore the first mentioned
manner (direct addition of color to the emulsion) is to be preferred.

After the experiments made by me, eosine mixtures acted equally in the
yellow and blue shade; likewise mixtures of cyanin 1/10 and eosine yellow
shade 9/10 were the most favorable. The process with eosine underwent
first of all a thorough test, of which the following are the results.

The color, solution I made as follows:

I. 0.5 grm. eosine yellow shade in 750 c.c. alcohol (95 per cent.) is
dissolved under good shaking.

II. 0.5 grm. eosine blue shade is also dissolved in 750 c.c. alcohol.

(The emulsion preparation I do not repeat, supposing that everybody is
conversant with the same.)

To an emulsion after Monckhoven's method, I add, before filtering, above
eosine solutions to 1,000 c.c. emulsion, 15 c.c. each of yellow shade and
15 c.c. of blue shade eosine; mix with a glass stirring-rod, filter, and
begin the flowing of the plates. On the contrary, to an emulsion made
after Henderson's method, double the quantity of coloring matter can be
added before flowing, without reducing the sensitiveness perceptibly.

Cyanin and eosine mixtures I give in the following proportions;

III. 0.5 grm. cyanin (iodo-cyanin) dissolved in 1,000 c.c. alcohol under
good shaking.

(All coloring matter solutions have to be filtered.)

To 1,000 c.c. Monckhoven emulsion I give:

25 c.c. eosine solution, yellow shade (I.).

5 c.c. cyanine solution (III.).

With Henderson emulsion I increase to double the quantity.

Further experiments taught me that even if 60 to 80 c.c., and more, of
these coloring matter solutions were added, and the emulsion was left to
coagulate and then laid in alcohol for several days, after which it was
washed well, so that hardly any coloration could be observed, it showed,
when making a copy of an oil painting, that the color sensitiveness of
the emulsion was not reduced, and that it had rather increased in
relative sensitiveness.

Anyhow, I put every colored emulsion for eight days in alcohol, having
experienced that hereby, after washing, j