HOME BREW 4X5 PLATES?

[Hologram]

these links are what i have been looking for-many thanks

hologram-have you done any of this or similar?

Yes, but for holography only.
In that case one problem was finding/producing a gelatin layer that wasn't too hard nor too soft. The hardness has a strong influence on diffusion speed of the sensitizing solutions. Sometimes it becomes difficult to achieve consistent results. Bath concentration, temperature, dwelling time may have a strong influence on grain size.
And as for using fixed out photographic/lithographic emulsions, this may add lots of noise. It looks though gelatin layers get marked by the removal of AgX grains. I guess you'd be better off using very fine grain emulsions when doing this.

 

[z-man]

transplanting methods is good

Yes, but for holography only.
In that case one problem was finding/producing a gelatin layer that wasn't too hard nor too soft. The hardness has a strong influence on diffusion speed of the sensitizing solutions. Sometimes it becomes difficult to achieve consistent results. Bath concentration, temperature, dwelling time may have a strong influence on grain size.
And as for using fixed out photographic/lithographic emulsions, this may add lots of noise. It looks though gelatin layers get marked by the removal of AgX grains. I guess you'd be better off using very fine grain emulsions when doing this.

H-

it seems to me that since holography has stricter requierments than those of 'art' photography anything you are doing is usable by those of us that are here for photography in its more commonly understood sense

are there any links you could provide that would show me the common working methods of home brew holographers?-

i mean in terms of 'plate' making---

ex: i have found out about a material in common use in the art world now--it called "multi media art board" and is made out of paper pulp and thermal set epoxy and it is translucent-

when i get some i will know if it is of any use --it is described as acid free and impermiable to water and "it does not buckle"

i am intending to use it as a support for images but it may prove useful for other applictns

pe's description above of the curtain coater will allow me to develope a modification of my present methods

it seems to me that if a find a support that is pre-coated gelatine-nothing else since the gel is for sizing so that paints/whatever get a good grip on the support, in a factory production line, it will be more uniform than anything i can produce-

re pe's contribution, re kodak production of photo plates by hand coating--these plates would be more uniform than my efforts, since, if you are hand-coating every day to meet production needs re big nos, you will get very good at hand coating

it may be that if i then over-coat with sensitzing solutions , these 'virgin' gelatine layers will, by obsorbsion, give me an emulsion that will be less varible in its characteristics , and i will find out when i do it

as you have pointed out, the gel itself thru it's physical characteristics , has a great influence on the final emulsion's spectral character--

if i can eliminate variables in any way i will gain since the variables in any of these emulsion issues make for a system that is so loose and sloppy that you can get lost trying to tack any one of them down so that you can finese the others into a tight predictable sytem, so that when you feed it an input, you can have a good idea of what it will give you as out-put

i have mentioned the old trick of fixing out a piece of projection print paper as an example

this is no longer necessary-you can get ink jet paper wiht a gel layer and many other characteristics that couild be used as a support for sensitizing with 'alt' process solutions

the use of of-the-shelf products intended for other use, in the manufacture of many things, is an old and still used way of getting uniformity in your own product

thank you for taking me around this corner-i do not yet know the neighborhood

vaya con dios

 

[Hologram]

are there any links you could provide that would show me the common working methods of home brew holographers?-

i mean in terms of 'plate' making---

You'd have to search on www.holographyforum.org

 

[Photo Engineer]

The process of sensitizing plates by imbibition or overcoating with dye is well known and can be found in a number of publications from the early part of the last century.

The problems with uniformity led to its abandonment in favor of the current methods.

PE

 

[z-man]

the problem with uniforms that fit lite tight

The process of sensitizing plates by imbibition or overcoating with dye is well known and can be found in a number of publications from the early part of the last century.

The problems with uniformity led to its abandonment in favor of the current methods.

PE

the problem with stroke induced selective memory loss led to the abandoned flavor of currants in meat pies. . . . .what was i saying?

pe-could you voluntier the general area of research so i can find these publications---when the bookstore " a photographers place " was still on green street in soho i built up a good library of late 1800's and early 1900's methods--my library went with every thing else when a 6 mo hospital stay led to the looting of my old apt-life in the big city. . .

was the repeatablity issue coming from the gel layer, or the brushing on method or the silver/whatever solution?

i think that if i can get a mass produced gel sized/subed/coated support then i have a known constant-the silver salt emul you psoted could be adapted as a 'sensitizer' or regular 'salted paper' solutions could be used

i have been given a formula for subing glass with chrome alum hardened food grade gel
so that the lite-sens gel doesn ot need hardener you then seal it with hardened food grade gel-when i can do it i will post

if i order "prepared" acetate --gelatine coated mylar-- and overcoat with ag/salt this will make film so--

i will laminate to a rigid support and have a 'plate'

the holo crew coat by spinning---i can get a kids paint spinner--any thorghts/;experience witdh spinning coatings?

how did kodak cut the large plate without lifting the emulsion at the cuts?

(why does a 1 or 2 stop over exp of a plain agno/salt emulsion go sepia?)

if i prepare a clean plate and then draw on it with photo opaque wax china marker the emulsion wont stick to marker when i caot plate so that when the plate is developed only image area will be in areas not opaqued with wax crayon and i expect that if emulsin is not hardened it will 'wash off' in the deveoper -if emulsion has alum hardener in it i may be able to transfer the emulsion over the wax marker to another plate and use that to 'print' a whatever on the prints made with the plate

this will produce a certain 'je ne se qua'--wala

vaya con dios

 

[Photo Engineer]

Kodak cut or scribed the emulsion surface before cutting the glass. IDK the details.

My references are Wall and also Baker on early emulsions up to the 40s.

Brushing introduced brush strokes, but imbibition of sensitizing dyes introduced other problmes of uniformity as the adsorption was not optimum in salted gelatin coatings. Again, I don't remember details as I never worked in this area.

PE

 

[z-man]

muchismas gracias

Kodak cut or scribed the emulsion surface before cutting the glass. IDK the details.

My references are Wall and also Baker on early emulsions up to the 40s.

Brushing introduced brush strokes, but imbibition of sensitizing dyes introduced other problmes of uniformity as the adsorption was not optimum in salted gelatin coatings. Again, I don't remember details as I never worked in this area.

PE

pe-thanx

vaya con dios

 

[knoxissimpler]

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)

wait, should this be 90 ml of water, or are you just switching off between ml and grams? (if so, is the next one that the silver nitrate is in in grams or ml?)

 

[rknewcomb]

I am so happy to see all this great information pop back up in a thread! I have tried a little bit to do this, but very much want to make my own emulsion for home brew glass plates. Couldn't be happier if I tried. Add big smile here!
thank you!
Robert N.

 

[Photo Engineer]

wait, should this be 90 ml of water, or are you just switching off between ml and grams? (if so, is the next one that the silver nitrate is in in grams or ml?)

All measures are in grams.

PE

 

[knoxissimpler]

thank you, but just curious (as I am a newb to the mixing of photo chemicals) is the water in developer, stop and fixer also measured in grams? or is that just a personal preference

 

[Photo Engineer]

Water and indeed gelatin, silver and almost all chemistry involved in emulsion making is done in weight/weight units due to ease of workup in the dark and viscosity issues. Processing solutions can be done vol/wt or vol/vol units. However, remember that viscous concentrates such as HC110, measured in volume must be carefully measured. You must rinse out the measuring container of the syrup. You can leave a lot behind in a measuring cylinder or cup.

This is why, in emulsion making, where gelatin is so viscous, that we use weight measurements. When you get the right weight, you have it 'all'. Also, reading a graduate cylinder or syringe in the dark, especially with emulsion, is very very difficult.

PE

 

[knoxissimpler]

thank you ^_^

 

[knoxissimpler]

sorta in a bind, I made the emulsion (finally got it approved), but tomorrow is the only time for another two weeks that I can use the darkroom... problem is, if the gelatin is solidified, besides using a hot plate, how can I melt it to apply it to the paper/ other material? I thought about using a copper coil with hot water running through it, but will the copper react with the silver chloride (I KNOW it will with any excess silver nitrate, but I do not believe that will be enough to cause major issues)... I do not know what to do, if someone could please post soon...

P.S.: the container I ended up using (since my other one broke) is unfortunately, plastic...

 

[Photo Engineer]

I weigh out the emulsion I need and it can go into a plastic, glass or Stainless container. Then I put it in a tray of water at 110 deg F and melt it. Then I add finals and coat the emulsion. Finals include hardener and surfactant.

PE

 

[knoxissimpler]

Thanks, I didn't know if the plastic would take the temp needed to melt the gelatin... I get to apply the coat in the morning, and check back in the afternoon (late) and the next day hopefully get results!... Since I can use plastic I decided that a double boiler would work... I plan to attempt to make an egg photographic (and for the rotting egg effect, I have stuff to take care of it... but it's kinda funny since I accidentally have turned on panoramic on my camera sometimes)... But just for the record, do you know if the copper will or will not react with the emulsion?

 

[Photo Engineer]

What copper?

Copper is a no-no for emulsions unless added as a specific salt to a specific emulsion at a precise level.

PE

 

[knoxissimpler]

what copper?

I was hoping to use a reverse condenser method (copper tubing with hot water running through it), but I figured (hence I asked) that it would displace the silver in this reaction
AgCl[aq] + Cu --> CuCl[aq] + Ag

 

[Photo Engineer]

If silver salts contact copper tubing it is not good for the silver or the copper. If copper pipes are used in home plumbing, or even iron pipes, this generally presents no problem as long as the water is filtered.

PE

 

[knoxissimpler]

I got to develop the first batch (since I was just developing, I was able to get some extra time by using the time slot of another class since no extra mess was made) and I couldn't even get the enlarger to expose one after a full minute, but the room lights do it in about four seconds... how much light do enlargers really put out?

 

[Photo Engineer]

Not much and most enlargers have UV filters whereas room lights sometimes have some UV.

So, depending on the emulsion, your result is reasonable. Silver Chloride emulsions have very little visible sensitivity and that is why Azo paper is a contact chloride paper.

See post #6 and my others here for more details.

PE

 

[knoxissimpler]

thanks, I know that at least one of the enlargers is like 20 years old, I might try that on a test strip, but I also have a little trick up my sleeve, Magnesium... I have been planning for a while to make my own enlarger and powering it by pure, burning magnesium ribbon... would basic magnifying lenses block UV? and is a UV filter in an enlarger removable? I don't have the resources for other emulsions, and I was hoping to transfer a prize winning image, could i do a contact print using a commercial photo paper print of the shot?

and also, could this emulsion be developed using a coffee developer? (just a thought, I am doing a LOT of projects in photography, mainly it has recently been centering on high speed photography and light paintings and controlled motion blurs, I, however, have been looking to expand my darkroom techniques)

 

[Photo Engineer]

Well, magnesium burns hotter than most think and burns more quickly. That is why it was used as a flash powder at one time. I do not recommend it!

The chloride emulsion is at least 5 - 8 stops slower than enlarging emulsions and is sensitive in a different part of the spectrum by a reasonable amount. Also, many lenses are partially opaque to UV. I would use about ISO 1 in a camera. I've used it in bright sunlight and that would be about right. Coated on paper will roughly double the speed.

PE

 

[knoxissimpler]

first, I'm not using it in a camera... yet, second, I have used magnesium before to expose images, just never in an enlarger (I mainly was thinking of it since it has a very high UV output [hence, its eye damaging powers] and I still would like to know if ordinary magnification glass would work (or if I really do need to get a special type of glass)
and also, would I be able to do the aforementioned contact print? I would hate to try without any basis first... I remember doing them with commercial photo paper a WHILE back, but have not tried on this emulsion... (you know, paper on paper under a light [in this case, a fluorescent bulb, but not multiples...])... and I am not using powders (or even a mixture of fuel and oxidizer) I am going really old school with this... magnesium RIBBON exposure... (back before the powder was used, I have seen units that had a roll of ribbon, and a chart of inches Vs time/exposure)

 

[Photo Engineer]

Yes, but today's enlargers are not designed for this so don't set fire to your enlarger or darkroom.

IDK about the lenses but they will pass some UV. The only thing is to do it trial and error.

Sorry.

PE