A real formula

[tars]

Hello, PE
I've been reading yours and others emulsion formulas in this forum, and I'm very interested in making my own emulsion, for papers. I really want to find a simple recipe of enlarging paper emulsion which doesn't need washing and that I could coat on artists canvas, too. In a brazilian book (Formulário fotográfico, by Reinhard Viebig), I found this one, and I wonder if you could give me tips or see if it will do the job. I'll translate the recipe:

Emulsion for Papers:

To emulsify any paper, you should first coat a layer on the support to be emulsified, with a fine brush or sponge. This layer consists of the following formula:
Potassium Iodide - 13,0 g
Potassium Bromide - 75,0 g
Starch - 17,0 g
Water to make - 1,0 liter

The emulsified paper, when dried, must be sensitized in the following solution:
Silver Nitrate - 50,0 g
Distilled Water - 1,0 liter

Let the paper float on this liquid and put it to dry in a dark place. Exposure, developing and fixing follow the normal processes used for ordinary bromide paper.

I found it interesting because it doesn't need washing as (I think so) the precipitate will fall on the Silver Nitrate solution container. It is not said, but I suppose that a starch glue should be made from the starch, and that will adhere the KBr and KI to the paper.
Do you think if I add some Thymol to the emulsion, its shelf life will be greater? Also, do you think it's a good idea to add the Silver Nitrate solution to the emulsion solution with more starch glue, and then coat it on paper/canvas, without washing?
Here in Brazil, it is impossible to find photograde gelatins, so this emulsion is very convenient, since it's easy to find cassava starch in the market.
I hope you can help me.
Thank you!

 

[Photo Engineer]

Well, to start with, this is not a typical silver halide emulsion. There is no gelatin involved. This is another type completely. It is outside the scope of my work.

I might add that many paper emulsions were unwashed, even with gelatin.

PE

 

[tars]

Well, to start with, this is not a typical silver halide emulsion. There is no gelatin involved. This is another type completely. It is outside the scope of my work.

I might add that many paper emulsions were unwashed, even with gelatin.

PE

Ok, thank you!
It's good to know that I can make silver gelatin emulsions without washing. I'll try to buy gelatin on ebay and give it a try. I don't like the sensitization mode of this recipe I posted... it may waste too much silver which is not cheap at all.
Can I use the emulsion formula you posted in this thread for enlarging paper coating?

 

[Photo Engineer]

The formula here, using ammonia, is not an enlarging speed emulsion. The enlarging emulsion uses no ammonia.

PE

 

[tars]

The formula here, using ammonia, is not an enlarging speed emulsion. The enlarging emulsion uses no ammonia.

PE

I found a very simple recipe in this forum that was tested, and you mean there that if I want a enlarging-speed emulsion, I should make a sulfur finish in the emulsion.
The link for the thread is the following: (there was a url link here which no longer exists)
Could you explain to me what sulfur finish would be? If I don't do this sulfur finish in the emulsion, will it be really impossible to use it for enlarging?
Sorry for taking your time...

 

[Photo Engineer]

Sulfur finish increases speed and contrast of an emulsion. In an enlarging speed emulsion, it is usually added at 100 mg of Hypo (pentahydrate) per mole of silver. This is based on grain size, and so a finer grained slower emulsion would need more and a coarse grained emulsion would need less.

You bring the emulsion to 60 deg C, add the hypo solution while stirring, and heat for 1 hour. You then cool. This is a normal operation, but temperatures may vary as well as hold times.

PE

 

[tars]

Thank you very much, PE! You helped me a lot.
Also, I think it's a good idea to add some Potassium Iodide to this formula, as it will increase contrast and speed too... am I right, or this is not a good idea in a unwashed emulsion?

 

[Photo Engineer]

You can use Iodide for this purpose but you must be careful or you will fog the emulsion. The question of how much and when to add it is critical and varies with each emulsion.

PE

 

[Frank Gosebruch]

Looking for dyes, additives or a formula to sensitize collodion to >800nm (infrared)

After reading your giant thread, I'm a little confused. But I am convinced, that you, PE, are the 'right man'.
There are lots of hints and advices for dyes to create an emulsion with super-panchromatic or, at least, expanded red or infrared sensivity. But these formulas are all just for dry plates.

My collodion plates are just sensitive to blue light.
After production of Kodak HIE was stopped and there was no other real infrared film material on the market anymore (forget Rollei and SPX, just 700nm / EFKE and Konica stopped production) there is no chance to continue real infrared photography.
So I just wanted to try some dyes to expand/shift sensitivity up to 800 or more nm with collodion wet plates.

The wet collodion process is devided in two parts.
1. The collodion
2. Sensibilization in silver nitrate sol.

Where, when, how and how much do I have to add the Neocyanine or the 3,3'-Diethyloxatricarbocyanine iodide.
Do I have to change the developer (iron(II) sulfate), then?
How about fixing, then? Any experience?
If it doesn't work with collodion, what is the exact procedure for IR-sensitive dry plates (up to 800-820nm or more)?

Sorry for creating another thread already in APUG. I'm a newbie here and I'm not used in the system, yet.

...and sorry about my horrible English!
Thanks

Frank

 

[Photo Engineer]

AFAIK, wet plate collodion has never been sensitized to anything other than blue. It is pretty much impossible to do with the technology invented for silver gelatin.

However, you might find a way if you are willing to experiment.

The method is very simple. You add the dye just before coating the silver halide on a plate or film. Usually, you hold the warm emulsion for 15 minutes. Then you ad any finals. Then you coat.

The amount of dye is based on grain size and can vary from 10 - 100 mg for every mole of Silver ion present. That must be determined by trial and error. Once set, it is firm at that level.

PE

 

[psykodaddy]

Hey Hey guys,

let's wake this one up

I started to gather some stuff around me to get started with glass plates soon. The goal is a DIY camera for plates of 30x40 cm!

Right now, silver nitrate is at around $300 per 250g here in Germany and I want to try a more budget-friendly version. It surely would be a lot of fun using PEs formula, though.

I found an emulsion from Foma in the Czech Republic...I love shooting their film and enlarging with their paper, so I was hoping their emulsion could be a good one, too.

Attached comes the datasheet of this emulsion, the link to the official website is: https://fomaobchod.cz/en/photographicemulsion/photographicemulsion/fotoemulsefomaspeedn1kg[74052]

What's your opinion on this emulsion, fellows? Or any other suggestions on a coating for my glass?

I can't read much out of this 'datasheet', but was hoping you can

In case someone's interested, I can buy in this shop excl. VAT...

 

[Peter Schrager]

It's a great place to start. I prefer to make my own emulsions especially POP WHICH IS printing out paper

 

[Dan Dozer]

A little late responding to the question about the FOMA liquid emulsion. It works really good for coating paper - just make sure that when you develop your print, your chemicals and wash water aren't too warm (keep them below 75 deg. F. or you run the risk of having the emulsion lift off the paper. Also, if you brush coat - do two coats. One coat won't give you enough contrast in your prints. If you coat with a glass rod - look up Denise Ross's book for that - it works great and you only need to coat once.

The FOMA emulsion works really well for doing bromoils. Look up Emil Schultz's books on that. I've had good results making my own emulsion from scratch (lots of recipies out there), but the FOMA seems to work best for bromoils.

 

[Trask]

It still shocks me when scrolling through “new posts” to see PE’s photo there as the OP — if only.... Gone but never forgotten.

 

[MattKing]

Gone but never forgotten

Unless of course he is up there and watching us but getting exercised because some of us have passed his post count .
I too miss him a lot.

 

[NedL]

For posterity, since it will change very soon

 

[MattKing]

Thanks Ned - I think!
(don't mention this to my wife)

 

[Sirius Glass]

Unless of course he is up there and watching us but getting exercised because some of us have passed his post count .
I too miss him a lot.

I purposely stayed below his post count while he was alive. I miss the private talks I had with him.

 

[ludwik]

In few places there is a something per mol of silver. (I'm beginner in this things) How to calculate it? Can you make example using recipe from first post?

Another question. reading a lot about the process I've seen someone adding silver nitrate from one syringe and bromides and iodides from the other syringe in the same time - both needles close together dipped in the hot gelatin on magnetic mixer. is any advantage/disadvantage of this approach?
Is the speed of silver nitrate injection depends on volume of mixed batch? somewhere here I've seen 1ml in 3sec. somewhere on youtube Ive seen 85ml in 2 minutes (so twice that speed). whats the best flow rate? (I made syringe pump out of parts from broken diy 3d printer so can set it exact )

Do I understand clearly that presents of ammonia makes emulsion 10 times light sensitive? (30-40iso? ) I need to buy some...

 

[koraks]

In few places there is a something per mol of silver. (I'm beginner in this things) How to calculate it?

A 'mole' is a quantity used often in chemistry. https://en.wikipedia.org/wiki/Mole_(unit)
You calculate the number of moles by dividing the mass of a compound by its molar mass. For instance, if you take 1g of metallic silver, which has a molar mass of 107.8g/mole, this works out as 0.0093 mole.

is any advantage/disadvantage of this approach?

Silver halide formation is kind of a tricky process. The exact conditions determine the distribution of grain size and shape, which can vary quite wildly. This is why you'll notice some seemingly arcane ways of combining liquids in emulsion making.

whats the best flow rate?

This depends on many factors, notably what kind of grain size and shape is desired.

If you're interested in these things, I would strongly suggest to pick up a textbook (or a couple) about silver halide emulsion making to familiarize yourself with the chemical and physical processes involved. You'll learn, for instance, that it's not as simple as "add X and the emulsion will become Y times faster". Silver halide emulsion making is a set of processes that interact in very complex ways.

 

[ludwik]

This depends on many factors, notably what kind of grain size and shape is desired.

For start I would like something that just works... an average emulsion that will be first step in this journey - something useful to make me shout: ITS ALIVE!!! a good starting point to improve and experiment with textbooks etc.

 

[koraks]

For start I would like something that just works... an average emulsion that will be first step in this journey - something useful to make me shout: ITS ALIVE!!! a good starting point to improve and experiment with textbooks etc.

In this case, I would suggest using Denise Ross' work as a starting point. See e.g. here: https://www.thelightfarm.com/Map/DryPlate/Recipes/TheRecipe/TheRecipe.html
But start by reading the practical guidelines here as well: https://www.thelightfarm.com/Map/DryPlate/Recipes/TheBasics/TheBasics.html

@dwross the author of the resources mentioned above occasionally posts here as well. Several other people have given her recipes a try over the years. I'd also recommend picking up a book of hers to get you going.

 

[ludwik]

I'm reading it now. (fortunately there is an online version so I dont have to wait for it)
at the start I will go with this simple recipe and then the one from this topic. 10 times higher ISO is very tempting.

 

[koraks]

10 times higher ISO is very tempting

So I imagine!
I only dabbled in silver gelatin emulsion making very little, but it was sufficient to realize I'd need to learn to crawl, then walk, and then maybe try to run...

 

[Udor]

When starting out, I found the work of Mark Osterman quite informative. Here is a useful link:

http://www.processreversal.org/public/text/Osterman_making_gelatin_emusion.pdf