Two formulae for adding IR sensitization to film emulsions

[David]

With IR film being increasingly rare, I set about finding a book that would describe how to make IR-sensitive emulsions. The idea being that with a dry plate camera I could make a plate and then sensitize it to IR or I could try sensitizing a standard film emulsion to IR.

N.B. that doing this is at your own risk and that you will be responsible for the proper safety and ventilation. This post is for information only.

The first formula will provide sensitivity up to about 8,900 Angstroms, peaking at 7,900 Angstroms. The second formula provides sensitivity up to more than 10,000 Angstroms (perhaps up to 12,000 Angstroms) but with much less sensitivity than the first formula except above about 8,500 Angstroms.

Sensitization by Bathing

Methods for sensitizing plates by bathing in solutions of dyes are very numerous. The following formulae will, however, be found to give satisfactory results. It is important that plates of medium sensitivity which work without giving much fog should be used.

Kryptocyanine and Rubrocyanine
1 in 10,000 solution of the dye in methyl alcohol 1 c.c.
Industrial spirit 165 c.c.
Distilled water to make up 500 c.c.

Bathe the plates 3 min. in this solution. Dry in a current of cold air

More concentrated solutions up to 10 times the above strength may be used, but the risk of fogging is correspondingly higher.

Neocyanine and Allocyanine
1 in 10,000 solution of the dye in methyl alcohol 6 c.c.
Industrial spirit 165 c.c.
Distilled water to make up 500 c.c.

Bathe 2 to 3 min. Cry in a current of cold are.

The stock dye solutions do not keep well. They should be protected from light and should be discarded after about a week from the time of making up.

Bathing Technique
The plates should be put into the dye solution in such a way that the liquid flows right over the plate without a stop. The dish must be rocked very thoroughly. After bathing, they should be drained carefully so as to remove as much as possible of the superfluous liquid. When put to dry, the lower edges or corners when draining must be kept at the bottom.

Drying
This should be rapid. An ordinary electric office fan is very useful for this purpose. Great care should be taken to make the drying as even as possible.

Dishes
Ordinary porcelain dishes may be used, but they should be kept solely for dye sensitizing purposes. The dyes will separate out on the surface of the dishes and should be cleaned off from time to time with a little spirit and cotton wool.

[ForenSeil]

Very interesting. Thank you for sharing.
I have some Kryptocyanine at home and never knew that I could use it for stuff like that before
I used it as solution for strong DIY pulslasers before for laser air breadown (very cool effect, a laser pulse which is strong enough to burn air)
I wonder if I can make an IR film from my Lucky SHD 100 with it.

Neocyanine and especially Allocyanine are not very common chemicals, I guess very hard to find.

[David]

I'll be very interested to see your results. If that works, I'll be trying it, too.

[ForenSeil]

I'm a skilled chemist but I just noticed that I'm a bit confused about the recipe