TJ-1 and exposure time

Simple answers are here! For Theory look in General Holography.
Viking

TJ-1 and exposure time

Post by Viking »

Hi there holographers

I have been developing pfg-01 plates in JD2, exposure time 8sec and developing time about two minutes.
I have changed to TJ-1 developer. The instructions say less than 30sec developing. Does this mean that the film needs much longer exposure time
or is TJ-1 really fast working???
My reason for asking is that even 60 sec exposure results in very light coloured plates with very very dim reflection holograms. A piece of film was left
in sunlight to test the developer. As this film got totally dark in seconds I believe the developer is ok.
I have spend way too much time looking for chems here in Greece before finally bying them from Photographers formulary, so my plates and film have
expired at least 6 month. After bleaching they look a bit milky too.
So is it that TJ-1 needs very long exposure time or are my plates too old and have lost sensitivity?

Thanks in advance
Colin Kaminski

TJ-1 and exposure time

Post by Colin Kaminski »

Long eposures and short development times are a way of creating small silver particles. I would keep the development time a constant and try different exposures. Especially for high spatial resolution work like reflection holograms. So try 8, 16 32, and 64 second exposures on a single plate. Then develop for 20 to thirty seconds.
Tom B.

TJ-1 and exposure time

Post by Tom B. »

What is the chemical recipe for TJ-1? I tried Google but no help. If it uses a rehalogenating bleach like JD4, my opinion is that it will not work well with a coarse-grained emulsion like PFG-01 since the results in my experience are too milky. I tried a number of recipe variations with PFG -01 and best results were with the original JD-2 formula.
Colin Kaminski

TJ-1 and exposure time

Post by Colin Kaminski »

Tom B.

TJ-1 and exposure time

Post by Tom B. »

Ah I see, it's just a more concentrated version of JD4 developer and the bleach is not defined. Odd that Google didn't find this, though some holoforum articles mentioning TJ-1 came up. I just tried Google again and no joy. Maybe some spider bait is needed to get it to index the wiki (or someone has disallowed robots somewhere).
Colin Kaminski

TJ-1 and exposure time

Post by Colin Kaminski »

I think the main problem is the content does not change enough so it comes accross as a dead site. The forum is indexed pretty well.
Viking

TJ-1 and exposure time

Post by Viking »

Hi Colin and Tom, thanks for your replies.

Tom, I am using Phillips Ferric EDTA bleach. I wanted a non shrinking bleach and was advised this bleach. TJ-1 was chosen because it contains mostly easy to get household chems.
Colin Kaminski wrote:Long eposures and short development times are a way of creating small silver particles.
Thanks Colin for this info. I have not come across it before.
I managed to make a few holos that I am happy with before I ran out of JD2. I realise that I should never have chanced chems before I got more experience. It is much too early for me to complicate things like this.
My main consern here is wether TJ-1 is supposed to need so much longer exposure time to work, or if my film has lost its sensitivity. If my film is dead I'll get some new one. If TJ-1 really needs very long exposure time, I'll go for another developer as I am still using the Integraf laser diode (very low power that is). Hope somebody with TJ-1 experience can help me clear this up.
Colin Kaminski

TJ-1 and exposure time

Post by Colin Kaminski »

In simple terms: Exposure to light activates the silver particles. Development grows them larger. Lots of active silver grown for a short time is smaller particles.
Tom B.

TJ-1 and exposure time

Post by Tom B. »

Colin Kaminski wrote:In simple terms: Exposure to light activates the silver particles. Development grows them larger. Lots of active silver grown for a short time is smaller particles.
I had never made that connection! I can see how this could potentially improve results with coarse-grained films like PFG-01. As for loss of sensitivity with PFG-01 film as it ages, I have experienced this. I think there may be some things you can try to revive it - I think I saw some posts on this topic here a long time ago... I can't say I ever had any success with this, but I didn't try very hard since I found that I liked the fine-grained emulsions much better, though these have their own problems.
Colin Kaminski

TJ-1 and exposure time

Post by Colin Kaminski »

The simplist is to use a 5% TEA solution and rinse completely in DI water. This picks up the speed more than a plain DI rinse. I tend to just expose longer in old films. However, I have stability on my side.
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