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HOME BREW 4X5 PLATES?

z-man

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Jun 23, 2007
Messages
142
Location
nyc
Format
Multi Format
SO I GET A 3.9X4.9 " PIECE OF NON GLARE FRAMERS GLASS

now what? my purpose is to produce a neg that is loosely the same as those that were used to make the salt/alb/cyano/vandyke etc that i make now with film negs

i can make paper negs with rc projection paper in camera and they work quite well but now on to the real thing-i want an emulsion probably gelatine that will emulate a colloidon plate

i think i want silver chloride but wile i have experience coating 'paper' and even polyester i never tried glass

the textured surface of the framers glass should reduce the subing needed but what should i start with for the gelatine emulsion?

if there are links to earlier threads please supply

vaya con dios
 
You say you want to emulate a collodion plate. Why not just use collodion and do a "real" wet-plate?

Over at www.alternativephotography.org (get that URL right?) there are a few articles on mixing emulsions or using Liquid Light premade emulsion to make dry plates.

And right here we have Ron Mowrey (PhotoEngineer) and his merry band of emulsion makers.
 
I am a very poor plate maker. My friend Mark is teaching me how to do it, but like everything else it is an art. I usually end up with emulsion dripping from my elbow.

Almost any plate of glass can be used, but it should be clear glass if you want a good negative. Silver chloride will be very slow due to the fact that it is mainly UV sensitive.

The emulsion formula that I posted here (SRAD - with ammonia) will give a reasonable blue sensitive emulsion in the range of ISO 6 - 40 depending on how you treat it.

That is about all I can add.

PE
 
EMULATION FOR THE NATION


thank you for the link

i don't want to use colloidon and i don't want to use any of the many ready made liquid emulsions

i am looking for the input of those who may have done what i intend to do or are doing someyhing similar

the input of pe will of course be my most valuable resource-but i am sure that there are others who have much to say about this

this particular project is a side bar to my present 'green' efforts

a gelatine emulsion on glass is what i intend to do by home brewing

i am presently in contact with someone who is doing it but he is a very busy man and i am hoping that some one on this forum can add to my mix

vaya con dios
 
melo jelo?


speed not an issue re silver chloride-what can you tell me about silver chloride only emulsions?

i suspected that your srad would be good starting point-will dig in to posts -the prodigious out put you have provided here makes good reading but i get lost in the go-to cirlces of trying to follow them

reminds me of the spagheti-code of interpreted basic so common in the 80's

could you direct me to mark or his writnigs if any?

pe without you what would we do? we would be lost in the wilderness and expire from exhaustion i suspect

i know that the subing you must do for glass is an important issue-thats why i thought of the textured non glare glass-its used to cover art so its spectral character should be good-what do you think?

regular float glass is high iron so it blocks uv more than you might be aware and that is what leads to the long exposure times in contact frames and i suspect the old glass negs

pe-- rescue me!!! dispatch your merry band of jelo junkies to my aid!!! dont let the high sherif of not helping ham and his nefarious crew of blahblahblogers capture me again!!!

silver chloride is the treasure, i suspect ,and i will guard it with my every effort

if its foolsgold than i'll be fooled and a fool-so what else is new

but seriously now-what do you think and what do you like?

vayacon dios
 
Silver Chloride emulsions will have a visible light speed of a minute fraction of an ISO value. They will need very very long exposures, especially with a more modern lens which blocks some UV. A quartz lens or older lens will help.

Mark is an instructor of alternative photography and a conservator at the George Eastman House, and does not publish on the internet. He does give workshops.

Neither Mark nor I sub glass plates. It is not necessary as long as they are well cleaned and use the proper hardener which is Ghrome Alum. I made the error of using Glyoxal, and was corrected by several friends who told me that the Chrome Alum binds better to the glass.

I would only use AgCl emulsions for making lantern slides not for making any sort of camera original. Even then, you will find that you need rather long exposures, as so much of the sensitivity of the emulsion is in the UV.

Both Mark and I use an AgBrI emulsion for in-camera and lantern slide plates and film exposures. Depending on emulsion, we get speeds from ISO 3 - 80 on film support or glass.

I have posted a starting AgCl emulsion here, originally used by my friend Bruce Kahn in his course on photography at RIT. It is here already, but if you can't find it, then I'll look it up and repost it.

For gelatin, use 250 Bloom Photograde Deionized Gelatin. This is available from the Photographers Formulary. And, BTW, I understand that this is genuine Kodak Gelatin from Eastman Gelatin.

PE
 
I'M BACK


pe

thanx-just got back from a 3day hospital stay-was takeing a lightmeter reading off the back of the "gate house" a 1800's pump house now part of the ny city college campus at 135th and convent ave

was asaulted by a maintainence worker employed by city college when i refused to move from a public access public domain area -city of ny public streets etc

the cops got him off me but i was taken to the em room and admitted for possible heart muscle damage-will get reports tomorrow

could you please post siver chloride emulsion?

will take your advice but still am interested in plain silver emulsion

can't do to much research on the web right now-to exhausted-you think that pf prices are ok?

vaya con dios
 
Wow! Hope you are OK.

And while I don't generally approve of the tort system, I do hope you consider legal action against your attacker and maybe even the college. Not talking millions here, but enough to make it stick and get the college to better train (screen?) their employees.

But really, I do hope you are OK!
 
That is outrageous. No one should be attacked for photography from a public place. Get well soon...
 
z-man;

I hope you sue the guy! That is outrageous. And, I hope you recover fully from the attack.

I'm sorry but I don't have Bruce's formula here, and would have to look it up. I will repost it ASAP, or post a URL for it. It is here on APUG. I should be able to find it.

PE
 
Ok, here is a repost of the formula copied from the other post here:
-------------------------------------------------------------------
To 90 grams of distilled water, add 5 grams of photo grade gelatin and bring it to 40 deg C. Stir constantly. When dissolved and there are no floaters of gelatin, add 3.51 grams of reagent grade Sodium Chloride (NaCl). (I find dissolving the gelatin first is best)

Note, stirring should be continuous, and strong, but should not whip air into the gelatin salt mixture. Don't overdo the stirring, but don't underdo it either. Overdoing it will give you bubbles, and underdoing it will lead to a bad emulsion with foggy large grains.

In another container, dissolve 5.1 grams of Silver Nitrate (AgNO3) in 10 ml of distilled water.

Bring the gelatin and salt solution to 60 deg C with stirring. Turn out the room lights and turn on a red or yellow safelight, and then add the 10 ml of silver nitrate to the salt solution as you continue stirring.

Set a timer for 5 minutes and hold the mixture at 60 deg C for 5 minutes then place in a light tight container and place in the refrigerator. This will keep for about 1 month with no deterioration, perhaps longer.

You can coat this on about any surface with a paint brush if you remelt it at 40 deg C. I suggest a good camels hair brush with loose bristles removed.

If you have trouble with even coating, add a drop or two of photoflo 200 to the melted emulsion. If you need hardening, add a few drops of 10% chrome alum to the melted emulsion. If you add any hardener, the emulsion must be used as soon as possible or it will set up to a putty like mass.

Exposure time will typically be in the contact paper range. I've used about 3 seconds to normal room light. You should get a good black image with a contrast of about 2.
---------------------------------------------------------------------

This is not the formula I use, due to the fact that I cannot get the same grade of gelatin that Bruce uses, and I coat using a coating blade for more uniformity. It was a fair starting point though. I hope it works for you.

PE
 
legal weasels ad nauseum


pe-an outrage to be sure and thanx to you and others for your concern-the aid of the nypd and st lukes hospital ems have made it possible for me to still be here to haunt and harrangue all and sundry

perhaps an email or 2 from interested parties to the chancelar's office of cuny(www1.cuny.edu) or dean occhiogrosso, counsel to the president of ccny(www1.ccny.cuny.edu) will wake them up out of the circle the wagons stance they are at present maintaining

as a 100% disabled spanish speaking muslim senior, i am a "protected minority" in 4 catagories but the fact is that any body treated as i have been can sue on the basis of rights violations and pain and suffering-to be continued to be sure

the thread elsewhere on apug where i and others have been censored and had posts removed for expressing our outrage with the racist posts of a apug member re nyc law changes and photographers/videographers, shows that idiocy still reigns supreme everywhere

pe-stupid question #1:

take a fixed out unexposed sheet of rc projection paper and 'sensitize' with a typical salted paper agchl solution-now what do you call it ??? is it a gel emulsion? does sufficient penetration of the gel layer by the silver chloride solution take place to call it so/ or does the solution just lay on top of the gelatine?

your thoughts please

vaya con dios
 

There is no such thing as a stupid question.

I would not call it anything in particular unless it worked.

Actually, I suspect that brushing on salt, then brushing on silver solution would make a salted gelatin emulsion with very slow speed. I have little experience with this though.

Sorry I can't be more specific.

PE
 

so then a precoated support of any kind if the gelatine/gum/starch?/casien/albumin/whatever is then overcoated with the light sensitve components would be the same as if u had mixed the components with the whatever and then coated a naked support?

or does the interaction of a mix as u compound it make something which is entirely a different animal than a precoated support then over coated with the light sensitve solution?

i am thinking i will try both ways but if one way is a dead end i would appreciate the waring

vaya con dios
 
 
bingo bango bongo i aint got to leave the congo

 
I've read this over several years ago, or something like it. It came up in an old Google search on emulsion making that I did way back.

As I said, I have little personal experience with these methods. I have seen it done though and it does work. That is all I can say.

The dip in dye method was used for years as a method to spectrally sensitize silver halides. At one time, the preferred method was to add the dye after the halide, not with the halide, as one has to be careful that there is no interaction during crystal formation. That is about all I could add.

PE
 

did you see the "curtain method" or the other? re glass support coating

brit speak gets me confused-i think the other mentioned may be the wire wrapped rod method i used every day in the 90's

pe did you mention a source for those rods somewhere?

vaya con dios
 
The wire wrapped rod is available from several sources. I no longer have the URL handy but one company is in Rochester, (Webster to be specific). It works well, but is messy.

The curtain method is good and also messy. I have seen several methods for coating plates. I show one of them in the slide show on making and coating posted in the sticky here in this forum.

Kodak used what is basically a wier coater with emulsion being deposited on a single large moving plate of glass which was then cut into smaller plates when dry.

The best plate coatings I have seen were done with the teapot method where a puddle of emulsion is poured into the center of the plate and then the plate is rocked to distribute the emulsion evenly over the plate. The excess is poured off from two opposite corners then.

This was a production method used early on before Kodak automated the plate coating process.

PE
 
pulling an emulsion


very interesting-esp the 'teapot' pour

the pulling of an emulsion with a wire wrapped rod is so much like pulling the ink on a silk screen frame that i was able to learn the "identicolor" way very quickly-it doesn't have to be messy if production speed is not an issue

it would be very easy to build a rocking table along the lines of the coil spring supported masks used by many to dodge or burn on a contact vacume frame-when u put the table in motion during exposure, the hard edges of the masks become soft on the emulsion and you can blend multi layer exposures that way

do you think that such a table would work for puddling and smoothing the emulsion , or was it done an easier/simpler way?

perhaps a pendulum suspension such as that recomended by kodak(eroniously) for producing spreads and shrinks which gave rize to the counterintuitive name "unsharp mask" would work?

by the way, for those who don't know, such masks are produced by controling the distance between the emulsions in a contact frame-emulsion to emulsion exact size dupe, emul up on top of emul up mild spread/shrink, emul up on top of emul down more size difference in spread/shrink

emul up, spacer, emul up totaly controlable and repeatable in thousands of an inch as needed for spread/shrink mask by selection of spacer thknss and time of exposure and choice of diffusion screen (same size as frame) over frame or not

saul bolanyos says that spirit leveling the table for the plates and then pouring a puddle and spreading/smoothing with a gloved finger on 35mm or medium format sizes is good enuf if your emulsion is without, or low % , alum hardener

any comments/thoughts?

vaya con dios
 
I don't think that Kodak ever built a rocker table that was as good as a human being doing it by hand. They went directly to the wier type curtain coater.

BTW, I've been told that to prevent frilling it is good to run a file along the edges of the plate before coating to give it some 'tooth' so the emulsion will have a better, rougher surface to cling to. Kind of like a small bevel that is frosted....

PE
 
hand made in kodak production venues?


pe-whats a wier type curtain coater?

the co in rochester that still makes/sells wire wrapped rods-what are listed under? press room/ prep supplies? darkroom ?

that rec re frilling makes me think that the idea of using the textured non-glare glass as a suport may be a good one-still can't find a local source for that glass

there used to be a kit u could get in craft shops for fast and easy 'ground glass' that was a spray can of some kind of etchant and it was low leval re toxicity -surface produced was alomst opaque tho so i moved on

any experience with optically clear rigid plastic as a support?-sheet acrlyc? lexan is available in .010" at home cheapo-i have located sources for gelatine precoated celulose acetate and mylar but they are non rigid and film base size- .005

the uv transparency of plastics versus glass is very attractive to me-i have had to move back to glass for my eye prescriptions for the uv blockng factor

i am convinced that the float glass -crown glass issues in old glass plates and the dif in uv blocking is important-the uv component in light sources and the various results depending on the mix of uv and visible-using open shade to gain contrast in the old sun powered production lines -is well documented

do you know if kodak used a special glass for the frames .back in the day ,that they put on the roof to spit out the prints? the 'green houses' that were sometimes special built for the contact printing production lines-special glass or was it what ever the contractor sourced and chosen by cost considerations?

old production methods are often not easy to duplicate because the commonly used off the shelf products used as components are no longer made or are a differnt thing entires
ly

time changes the name and not the composition or the ingrediants and not the name in my experience

vaya con dios
 
I know little to nothing about the details of Kodak plate making. It ceased ages before I joined the company.

The wier type curtain coater was basically a slanted metal plate with a trough at the bottom. It was held a few mm above the moving plates and was heated with water. Emulsion cascaded down the slanted plate and filled the trough and then spilled over the edge in a cascade like a waterfall. This gave it the name curtain coater.

This is used today to produce high speed color coatings with many layers at one time. However, the design of the machine is different.

The URL with direction to the wire wrapped rods is somewhere on APUG. I have little interest in them due to the mess you make using them and the high consumption of emulsion making a coating.

I want to do things as cleanly and as inexpensively as possible.

PE
 

I wouldn't want to try wire wrapped rods now that I've experienced blade coating.
My blade was very much cobbled together, but extrapolating the results I got out to PE's properly made blades, I would suggest that they are probably the cleanest and most efficient method of homebrew coating.
They are very controllable as regards coating thickness, and the emulsion doesn't go everywhere when you use them, as I imagine it would with a wire wrapped rod.
 
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