Taking a leap into emulsion making

[argentum_et_lux]

I have been lurking on APUG for quite some time and have been studying many of the old photography methods. Finally decided if people like me keep lurking this forum is going to die off.
I hope there is some way to get more interest into the topic of emulsion making as I look there were a lot more posts in the past than there are today. I see an increased interest in glass plate, tintype, etc. photography online but it does not seem to be translating into more interest here. I hope we can convince PE and others to write more photo engineering information as I know I find the science of photography to be as fascinating (or more so) than the rest of the photography process.

Anyway been setting up a chem lab/darkroom and will be testing various formulas that I have found here and in old books. I hope to be able to contribute something useful as well. I am sure my significant other would like to thank APUG and The Light Farm for making me obsessed with photography again and the loss of space taken up by cameras, film, and chemicals.


Chris

 

[darkosaric]

Welcome to APUG Chris , nice first post!

 

[dwross]

Welcome, Chris!

You're going to have a great time. I hope you post often.

It's easy to fall away from APUG because it's so much more fun to be in the darkroom or behind a camera than sitting at a computer . I'm certainly guilty of that, but as you so eloquently expressed, if we care about the continuation of this corner of photo history, make time to type!

Best of luck and fun,
d

 

[studiocarter]

Hello,
I've been ordering stuff on line and shopping at thrift stores. Today I got a 120 degree F warming plate for $1
Tomorrow will be like Xmas as things are delivered here.
Not done yet by a long shot. There are so many things needed to do this.
Michael

 

[Photo Engineer]

Just remember that most of those old books are either outright wrong or leave things out on purpose or by accident. In addition, most all of them assume active gelatin which is not sold now AFAIK.

PE

 

[DannL.]

Some thoughts . . . I consider coating dry-plates with a ready-made emulsion such as Rockland's Liquid Light a "Gateway Process". And this is where I am. If and when I can coat a dry-plate with a premixed emulsion skillfully, then I'll move into making emulsions myself. It's been 12 months now, and many plates later (4x5, half-plate, 5x7 and 8x10), and I'm still learning how to coat. Tackling it from the other end would be a plan, but consider the possibility of using a lot of emulsion while learning the idiosyncrasies of coating.

 

[Pioneer]

But active gelatins can be made can't they?

 

[Photo Engineer]

Dannt, good method for learning. I am an abysmal coater of plates using the "pour" method, so I use my own way and it works.

Dan, you cannot make active gelatins. You have to add the proper chemicals and treat the emulsion for the right time and temp. That chemical is Hypo, and you have to determine amount, time and temp by trial and error.

PE

 

[Ian Grant]

Sulphur Dioxide can be used to Activate Gelatin, it was used to bleach gelatins during manufacture although it stopped being used for Gelatins for food use over a 100 years ago.

It does work

Ian

 

[pdeeh]

I've googled "active gelatin" but am none the wiser as to what distinguishes it from any other gelatin.

Could someone give brief explanation?

 

[Ian Grant]

Activated Gelatin usually has a bonding with other elements or compounds, in photography it's sulphur sites that are important.

The term is also used in the drug industry where a drug is attached to gelatin.

Ian

 

[Photo Engineer]

Here is a previous discussion on some of this topic: (there was a url link here which no longer exists)

Making inactive gelatin involves the oxidation of active gelatin to remove the sulfur compounds. Once removed they are hard to place back into the gelatin so we use hypo as the sulfur carrier and it works just fine. Others use thiourea which is also just fine.

PE

 

[pdeeh]

Ian, PE - thanks.

 

[PKM-25]

Welcome from a fellow Colorad'n! I do find this interesting stuff but let it be known I am also doing my best to push the ugly Industry threads to the bottom of the feed.

 

[dwross]

bump.

 

[Pioneer]

Ok. I am ready to get started but I need a list of materials to start with. And obviously I have many, many questions.

I am assuming that all of this is done in the dark, or is it possible to do this under a safelight at least? I can be quite clumsy in full daylight. I am imagining the disasters I could create in complete darkness.

Next, my current darkroom is a dry darkroom. To develop prints I typically insert the prints into an old film box to carry into my bathroom where I develop them in the bathtub, a back breaking activity that is becoming more and more difficult as the years progress. I do have a red safelight bulb inserted into the vent fan/light. Since I obviously can't keep the bathroom locked off for long periods of time, how much time will this take to fully complete, or at least complete to the point where I can open things back up again. Developing negatives or prints takes a relatively short time and the bathroom itself is not completely disrupted, only the tub.

So, what materials are best for a total newbie getting started on his own, can this be done under a safelight (if so, what kind), and how long will the bathroom be out of business?

 

[kb3lms]

Dan,

You can make emulsions under red safelight. The emulsion is only sensitive to UV and blue light until you add dyes to extend the spectral response. (For ortho film you can use erythrosin, aka FD&c Red #3) Even an ortho emulsion sensitized this way will pay no attention to a red safelight.

My darkroom is dry and I have made several emulsions in there. As long as you have a way to maintain a water bath within reasonable temperature limits you don't need a sink. I have used a hot plate in the past but have settled on a small crockpot.

Jason

 

[Photo Engineer]

As for a bill of materials, you need Silver Nitrate, Photograde Gelatin, and Sodium Chloride or Bromide. You also need a formula which includes quantities needed, temperature and times.

All of the chemicals are available from the Photographers Formulary. Others sell these things, but the Photograde Gelatin of most companies is somewhat lower in quality. The Formulary sells genuine Kodak gelatin. Food grade gelatin contains Sodium Silicate as a drying agent and can cause problems.

PE

 

[Pioneer]

Ok.

Clean off some countertop in the darkroom.
Go to the big box store and find an inexpensive crock pot.
Call Photo Formulary on Monday.

Got it. I'll be back with you when all that is in place.

Can I use regular copy paper to spread this emulsion around on or do I need to find something different?

 

[Photo Engineer]

You need a hard press paper of 100# or greater. Strathmore Smooth is quite good and comes in pads at art stores.

PE

 

[Pioneer]

Great. I'll head to the art store tomorrow. Anything else I should look for while I'm there?

 

[Photo Engineer]

Well, you need some method of coating the emulsion. A puddle pusher with shims is nice. A brush is ok if you like the artsy effect. There are several methods.

PE

 

[pdeeh]

Can pretty much any old glass rod be pressed into service for coating? So long as it's perfectly straight?

 

[Photo Engineer]

Yes, as long as you use some wrapping to gain a gap between the rod and paper. I use the words shims earlier as just about anything will do of the sufficient height. I use 2 layers of Scotch Tape. This is about 5 mil and lays down just about the right amount of emulsion.

Wire wrapped rods also work well. Doctor blades are the best, but I have stopped having them made, however the plans are in my book.

No matter what method you use, you also have to provide length of paper for swelling of paper at the starting end, and you have to provide for runout at the end of the coating in case you don't pour enough or use enough.

Coating is an art gained by practice. You don't paint a masterpiece on your first try.

PE

 

[pdeeh]

Ah that's a bit of information (gap) I was missing. thank you./

No gelatin emulsions for me (yet) but I'll be having a fiddle with salt and/or vandyke in the not too distant future I hope.