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  #21  
Old 18th February 2013, 01:14 PM
Terry S Terry S is offline
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Thanks for that Les. Interesting to hear back from you as the OP but a shame you were unable to continue with the project.

Since posting earlier this morning, I have been sat at the computer and have done an awful lot of reading but am still none the wiser really, as the LE is supposed to be quite good at sticking to the majority of things.... So I don't quite know where to go from here apart from continuing with my experiments.

I've just ordered a 'Silverprint' publication though, which I'm hoping will be of some help both with my Uni project and getting some of the LE to stick to a surface... ANY surface!!!

http://www.amazon.co.uk/Silver-Gelat...?ie=UTF8&psc=1

Terry S
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  #22  
Old 18th February 2013, 02:58 PM
paulc paulc is offline
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Originally Posted by Terry S View Post
This time around, it seems the emulsion didn't adhere to the primers at all (despite these being recommended) as after processing, the areas around the primers were blackened as expected, but there appears to be NO LE at all on the primers!?!

Can anyone who has used some brand of LE advise a complete beginner at this?

A subbing layer needs to be applied to the surface and allowed to dry before coating with LE. This subbing layer is usually a thin coat of gelatin solution with the addition of a hardener. I usually mix a couple of grammes of photo grade gelatin in 100ml cold water, allow to soak for a few hours. Warm to around 40C, stir until the gelatin has disolved, then filter. A drop or two of alcohol helps to disperse bubbles of air, but it is best left to stand for a while.

For absorbant surfaces, coat a thin layer of the subbing solution on and allow to cool. Place in to a hardener bath (either chrome alum or formaldehyde) for a few minutes. Hang to dry in a dust free area. Once dry, repeat the above process twice more for a total of three thin coatings. The LE can then be applied, preferably in two thin coatings as per instructions.

Non-absorbant substrates also benefit from a subbing coating - On glass, I usually do two thin coats of the above gelatin solution, hardening each as I go. Not tried aluminium as I'm sure it would react in the fixer bath unless totally sealed (You did know that aluminium can be used to precipitate silver out of spent fixer ?).

Have heard of PVA being used as a subbing coating on some substrates, usually with the addition of Silane, but not tried this myself.

One point to bear in mind with non-absorbant substrates - They must be scrupulously clean. The tinyest hint of grease/oil will cause problems.
Depending on the type and quality of paper, they may benefit from a presoak in hot water and dried - Some papers will shrink unevenly so this helps to mitigate the problem after applying LE.

Last edited by paulc; 18th February 2013 at 03:03 PM.
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  #23  
Old 18th February 2013, 04:27 PM
Terry S Terry S is offline
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Some interesting points there Paul = many thanks.

The thing is, both the instructions with the LE and from what I've read on the internet at various places this morning, don't mention using a subbing layer at all! I did come across the word and it's use though on another site about other alternative processes.

Out of interest, where you do normally / easily get your photo quality gelatine (is there a 'vegetarian' version out there at all I wonder?) and hardeners from?

About 35 years ago I do remember buying formaldehyde over the counter of Boots the chemist (those were the days when they would sell a school boy just about any chemical you asked for = including the ingredients to make rockets and smoke bombs with your chemistry set!)

Terry S
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  #24  
Old 19th February 2013, 12:04 AM
paulc paulc is offline
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Quote:
Originally Posted by Terry S View Post
Out of interest, where you do normally / easily get your photo quality gelatine (is there a 'vegetarian' version out there at all I wonder?) and hardeners from?
Silverprint is the main source for photo grade gelatin, although I have used cheap stuff from the local supermarket in the past with mediocre results. Same source for Chrome Alum - Just looked up the price Don't remember paying that much last time I purchased some. Paraformaldehyde or Formalin solution can be obtained from the likes of Bonnymans but shipping charges may kill that as a source. If you send me a PM, I may be able to find a source closer to home...

As for a vegetarian alternative, that would have to be a PVA solution as mentioned earlier, but the LE would still be from a bovine/porcine source.
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  #25  
Old 19th February 2013, 12:35 PM
Terry S Terry S is offline
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Thanks for the info Paul.

Researching some more, it seems that Formaldehyde can be obtained on a GP prescription for verruca's and the like (now where can I catch one from?...) and it can be bought on line, but in rather large quantities.

Reading more though, it seems to be a rather vile substance to use and I have no where ventilated enough indoors or dark enough outdoors to use it with light sensitive materials. How uninformed we were allowed to be 30+ years ago when I last bought it as a teenager over the counter at Boots.

It also appears to be available on ebay for use with goldfish ponds, at not to high a cost, so if I do decide to get some, I might go to a local fish supplies stockist to get it.

After more reading, I even try going to one of the local funeral directors with a small bottle in hand, as they use it all the time apparently.

I also looked up Chrome Alum and it's about £20 for 100g PLUS p/p from Silverprint but only about half the price for the same INCLUDING p/p on ebay...?

Before I purchase either though, I'll try out PVA first as an alternative vegetarian source. I have coated some paper last night, so will now also give that a go and see how it reacts.

It did also totally slip my mind that LE will of course have some animal gelatine in it (doh!) but if I can reduce my usage of it, all the better. Out of interest during my reading yesterday, it does seem that the main film manufacturers have been looking into a vegetarian version of gelatin for some time and the results are just as good as with the current bovine source, but the longevity / keeping times and quality of it aren't quite as good as yet.

Terry S
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  #26  
Old 19th February 2013, 09:45 PM
paulc paulc is offline
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Quote:
Originally Posted by Terry S View Post
it seems that Formaldehyde can be obtained on a GP prescription[snip]Reading more though, it seems to be a rather vile substance to use and I have no where ventilated enough indoors or dark enough outdoors to use it with light sensitive materials.
The hardener is only used when coating the subbing layers. As this does not contain any light sensitve materials, it can be done without any ill effects in daylight.

There are are plenty of other household chemicals just as dangerous as formaldehyde, but we still keep on using them. Two examples that spring to mind, drain cleaner, some can contain up to 97% suphuric acid. Household bleach containing sodium hypochlorate, which when mixed with an acid gives of chlorine gas.
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  #27  
Old 20th February 2013, 01:05 PM
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bsdunek bsdunek is offline
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Most of my LE is on 9X12 watercolor paper, and I dry them on kitchen cooling racks like these:

http://www.amazon.com/Wilton-2105-45...ng+drying+rack

I put them in a cabinet in my darkroom and close the doors. Seems to work fine.

I also coat some 3X5 index cards at the same time to use as test strips.

I did coat some 12X12 ceramic tiles, which I first coated with matt clear Krylon spray. Had no problem with the LE coming off.

I use Liquid Light, and have had good luck. I do find that drying time doesn't need to be long. Even if it is still sticky, it works well. Stop bath is not recommended - I go straight from developer to fixer. It does shorten the life of the fixer, but I guess that's part of the price.
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  #28  
Old 21st February 2013, 02:05 PM
Terry S Terry S is offline
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Thanks again for the info Paul and Bruce.

Well, another afternoon was spent in the darkroom yesterday, after coating various papers, stones and aluminium food trays with various subbing layers (one and two layers as well as none on each of the above) the previous day, to give them 24 hours + to dry before use.

I used water-based primer for wood, metal etc. as well as oil-based exterior satin varnish and pva. The LE adhered to all of them fine. BUT when put into the precessing chemicals, either the LE came off totally straight away (as with the primer, varnish and PVA) or a bit slower on the watercolour paper when not coated at all = until the fixing bath.

I did manage to get around about a 50% of the initial image to the washing stage on un-subbed watercolour paper but the LE was very fragile and would smudge and come off if the water bath wash jet or anything else touched it at all.

In the bottle before warming up, the LE is quite solid and in daylight before processing, a test amount adheres to all of the surfaces fine.

I am now thinking that it would be best to start a fresh with a new bottle of LE as the one I have is second-hand and about 10 years old. Despite this, it does give a very good image on the watercolour paper when it first comes up in the developer, so I can only presume that through age that it is not holding together when warmed and then put onto a base???

As one final test, I took a test piece of each sheet of various coated surfaces, which had been left overnight to dry, at the end of the yesterdays printing session.

I put them all separately and gently into cold still and then running water at about 5 degrees C. Surprisingly, the LE detached itself quite easily straight away and when touched very gently smudged and came right off. Now I thought that the LE should have a much higher melting temperature?

So with all of this info, would I be correct in thinking that the LE is past it's best and I would be better off starting from scratch with a fresh bottle?

I have to order some other darkroom goodies and film, so now would be the ideal time to order anyway.

BTW I also received my copy of 'Silver Gelatin' from Amazon yesterday = cheaper to buy from them than direct from Silverprint = the originators(?) and having flipped through it and read a few chapters and an excellent read and set of pictures it is.

One final question about the subbing though Paul:

I have ordered some Alum initially to try as a subbing base both for my current LE and my new bottle. You say it is to harden. Do you mean that the LE is put on top of it? I would have thought that a little should be mixed with the LE directly, so that it absorbs it, or does it does this anyway from the bottom? I have flipped through the above book and looked at many internet sites and can't find an answer to this and how it works? Can you help as it just seems to me to be a bit back to front some how?

Many thanks,

Terry S
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  #29  
Old 21st February 2013, 02:37 PM
Mike O'Pray Mike O'Pray is offline
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Sounds uncaring as it involves you in expense but I hope your conclusion is correct, Terry, and that the age of the LE is the problem. I can't ever recall seeing anything about LE giving as many problems as you have and I always understood that material such as watercolour paper could be coated directly without a problem. In short I had assumed that LE wasn't that difficult a process.

Let us know how you get on. I have often thought about trying LE myself but after reading what prep has to be done and what your problems have been, I'll hold back until you report a success.

Mike
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  #30  
Old 21st February 2013, 10:08 PM
paulc paulc is offline
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Quote:
Originally Posted by Terry S View Post
In the bottle before warming up, the LE is quite solid and in daylight before processing, a test amount adheres to all of the surfaces fine.

One final question about the subbing though Paul:

I have ordered some Alum initially to try as a subbing base both for my current LE and my new bottle. You say it is to harden. Do you mean that the LE is put on top of it? I would have thought that a little should be mixed with the LE directly, so that it absorbs it, or does it does this anyway from the bottom?
Get yourself a plastic knife and use it to cut/slice/dice the LE in to chunks that can be shaken out in to a smaller container. Only ever melt a small quantity (I usually add an equal measure of water). Repeated heating of LE will increase the amount of fog, and if overheated, the setting properties will be affected.

Hardener should normally only be used with the subbing coatings - I favour applying the gelatin subbing solution, allowing it to set, and then transfer to a hardening bath. When Chrome Alum is mixed with gelatin, it only has a useable working life of a day or so. Unless you intend to use a batch of LE in a single session, I would avoid mixing any hardener in - Very doubtful there would be any advantage anyway.

There may be a slight hardening effect from the subbing layer into the LE coating, but that would only be unqualified conjecture on my part - For a definitive answer, you'd need to ask a photographic chemist.

Last edited by paulc; 21st February 2013 at 10:12 PM.
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