I really admire you guys making these emulsions. Truly fascinating. I'm looking forward to the results of the OP's emulsion.
I'm following your experience with interest. I too am in the middle of making my first emulsion.
I posted a thread earlier (misspelled 'a femulsion formula I've found') which I've been working on. I think I rather rashly said something like 'I'll be mixing it up this week'. That was about six weeks ago :-o
O.K. it is a learning experience, I've wised up a bit now, after running into several brick walls!
Not least was working out how to manufacture my own 0.880 ammonia.
Now, I am a complete novice with very little experience to share, I'm behind you by the sounds of it. But here's two suggestions, which might be of interest.
Fisrt one is that I have lightproofed my emusion vessel, rather than the fume hood. (My fume hood is the open window of my garage ;-)
I took a 500ml brown glass bottle. Brown may well be 'safe' anyway, but to be sure I painted it with Rustin's stove enamel. This is black heat resistant paint. I fitted a cork with a glass tube vent, bent over to act as a light trap. I painted the cork and tube black, too. This sits in my water bath which is stainless steel and opaque and I place a sheet of aluminium foil over the top with a hole for the tube, just as belt and braces. The only bit where I need some darkness is adding A > B, which I can do in a changing bag or in the darkroom. I then fit the cork and then take my light proof bottle to the garage where I can then cook my emulsion for as long as I like in daylight...
Second suggestion was I decided to try stripping some old plates and coating them with a 'dummy' emulsion of gelatine and food colouring (with some chrome alum).
What a complete nightmare!!!
Obviously there is a lot of skill to hand coating a glass plate and I most certainly do not have any of it!
I got emulsion everywhere, my coatings were uneven, the plates where not clean enough and didn't 'flow' well at all, I got coating twice as thick on one side than the other and plenty of emulsion on the back to glue the plates to my drying slab...
First attempt was a total disaster. Second attempt was only slighly better, but I am slowly getting there. I need to spend a bit of time fully understanding the importance of temperature and the effect of the chrome alum. I will be making a post to plea for help from some of the experienced members later...
Point is, I am very glad indeed that I was only playing with food colouring and gelatine, and not my valuable silver rich emulsion - most of which would have ended up on the bench, probably ;-)
I will not be coating with real emulsion until I get my act together with the coating technique... I'm not sure if you are doing a glass plate or a paper emulsion, but I would certainly try your coating methods out on a dummy emulsion, first!
Emulsion coated glass or paper shelflife?
Reading with great interest, making notes and paying attention. But, a question.
If one were to coat a glass plate with this emulsion, what could be expected in the way of shelf life? Does a glass plate need to be shot within a certain quick amount of time or will it last a few days?
My paper coatings seem to last at least a year, but film emulsion coatings are fogged after a few days or so. I have not been using the stabilzer, as it is too hard to get and too expensive. I'm waiting to solve some problems with the film emulsion that are not present in the paper emulsions.
I agreed that it is best to practice coating in the light with gelatin containing a food dye. Just remember that the food dye changes the gelatin coating properties as food dyes are often sulfonates. Also, remember that the real emulsion is thinner at the same gelatin content due to the effects of the crystals suspended in gelatin. So, 10% gelatin emulsion behaves like about an 8% or 6% plain gelatin or gelatin with food dye.
There are a number of types of black plastic bags and black plastic bottles on the market. I buy them from the Formulary. I bottle and ship emulsion that way in a bottle then a bag.
"I have not been using the stabilzer, as it is too hard to get and too expensive".
So may I ask, what is the stabilizer agent?
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Tetra aza indene, given in another post here and in Jim Browning's formula.
Whirring , whirring, whirring!
This is so exciting. I decided that I was going about the thing all wrong like, so I revised it a bit. I tore down my fume hood... contraption today. My mentor was giving a tour or the lab to new students throughout the day (classes at UK started yesterday), so the spectacle (it was a sight to see!) was gone for all but the first ones
I ended up taking my 1L steel inversion tank to mix the emulsion in. It hit me after reading my emulsion bible (they mention it). The only problem I had was draining whilst washing (I used a clean cheesecloth instead of a mesh- lesson learned! Next time, mesh or screen it is!).
I used distilled water throughout the washing process, per PE's suggestion. I did a 10 minute fill/dump process for washing for 2 hours... I hope that was sufficient. It did wash clear by the end of the washing.
Temperature control with the SS tank was MUCH easier than wonderfully non-covective(?) glassware...
I also learned that gelatin is a PITA to dissolve completely, even in really hot water.
...In any event, the run I did last week I knew didn't turn out (first try, sorted out kinks in my process). I threw that out, and made the entire thing in one go today, carefully documenting everything.
Tomorrow is Friday evening, so I'll coat and print one sheet tomorrow. My el-cheapo $15 red safelight burned out (after 45mins of use?), so I have to get a new one tomorrow as well as some Sodium fix...
As per suggestion, I'm going to document everything online on a website (either a personal one or the UK site), so I'll post a link to that as soon as I build it!
I use my wife's old panty hose to hold the emulsion during washing. Just cut a suitable piece from the toe and stretch it, then put the shredded emulsion into it and submerge into the wash water.
The wash is usually complete, when the wash water does not become cloudy when a drop of residual hypo test solution is added. (This is just silver nitrate in acetic acid)
I just pour some wash water into a beaker and add 1 drop of the test solution. If a cloudyness is observed, then salts are still present. Now remember, this is a VERY rough test and can cause fog if you go too far. At Kodak we used a precise measure of the conductivity of the wash water.
A better suggestion and far stronger than "panty hose" are the bags available from home brewing shops designed to drain the juice from fruit while retaining the pulp.
Okay! Here we go.
I must say, that while I coated my first test sheets of real emulsion, I got a bit pretentious and put some developer on my glove... just to see if the scrap of emulsion would, in fact, turn black. It did, and I jumped around the house many times in euphoria that I didn't screw up... completely.
Next, I dabbled on a piece of glass, developer in a puddle to see a black, and then a few drops of fix to see if it turned clear. It did, so I knew that I was on the right track!
So I grabbed a 4x5 negative and printed it on a 135mm lens about 5 inches above the baseboard at f/4, on my enlarger, this is very bright. A test strip of 2 second exposures from 2 to maybe 8 or 10 (I don't remember, didn't write it down because normally I can see the difference in shades).
This yielded a very fine... grey blob!
Above was coated with a sponge brush. I found on this particular paper (Strathmore drawing paper), it gave a smoother finish than my other attempt: the BRUSH!
On the brush, however, I did give the paper a second coat (the first one is one coat). This seemed to improve maximum density... I'll stick these all under my densitometer tomorrow for a more accurate reading (in comparison to my maximum black tests).
In any event, I decided that my previous attempt was too short of a time, so I exposed for 32 seconds for the heck of it. Result? slightly more recognizable.
I definitely did not like the brush strokes. I need to work on those though.
My main concern is the fogging around the image. This paper is creamy colored, but I'm certain that something has fogged or is fogging. I suspect my safelight- I'm using an OC lamp because my red lamp burned out today on me.
Is an OC lamp safe to use with it? Is OC OK for ortho?!
I also altered my formula procedure in that I ripened for one 45mins on the last ripe, and I added the KBr "fog controller" 20 mins after I started that, because I forgot (I figured better late than never?). Also, I wasn't sure to start that ripen time from when I immersed the emulsion into the water bath, or when the emulsion melted. I went with immersion time.
So next time I mix this up, I'll do it on a day I don't have school so I can do the 6 or 7 hour procedure without staying till 8 or 9, as well as: decrease the B>A time to 20secs, final ripe time for 90 minutes.
Tomorrow I go shopping for a decent paper (i.e. one with more white tone), as well as a nice brush.
The original image I'm printing, if you care to see it:
Shot in 4x5 with an enlarging ektanon at f64
I'm getting there, slowly but surely. This is more difficult than I imagined!