Homemade Plates

Starting point for beginners questions.
Heferkimbo
Posts: 16
Joined: Sun Mar 26, 2017 9:13 am

Re: Homemade Plates

Post by Heferkimbo »

Ok guys, i need ideas, this is driving me crazy... I can't seem to get clear plates and i am being very very careful. The first time i didn't understand why i was getting those "black" spots after the ascorbic bath. But now i think it was because i failed to completely remove the silver soln. from the plate and after it dries, it leaves saturated areas with more silver that turn black from the ascorbic bath.

To avoid that problem, i started using a silicon spatula to remove any drop in the surface of the plate (instead of a ruler with a tissue), but they still fog. On some plates it's horrible, on others it is just around the edges. Will 10 minutes in cold running tap water (how cold?, ice cold?) as mentioned in the tutorial remove the fog or just reduce it?. I know veil coating will leave thicker areas in the bottom of the plate (i am careful to let the plate drip for 15 secs. and the place it in a flat surface), but why do they even get fog in the middle?. Will mold coating remove my fogging because of its very flat surface?

Here are some examples of the results i'm getting... the "a" plate is before the ascorbic bath and "b" is a different plate after the bath, as you can see there is fogging, but not as bad as "d". The "c" plate has it around the edges and a somewhat clear center. The last image are plates "c" and "d"... the fogging looks worse under the green light and the camera makes it even darker. You also have to consider that i have never seen a holographic plate before, should they look like the clear area in the middle of plate "c" under the green light?.
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I forgot to mention how it fogs: after the ascorbic bath the plates look very clear, they just become a bit darker (because it turns yellow right?). I then rinse them in DI water and remove the drops of water with the clean silicon spatula. The fogging/darkening begins after it starts to dry, around 5~7 minutes in.

The Ascorbic soln.:
-500ml DI water
-1.4 gr. Sodium Hydoxide
-10 gr. Vitamin C*

*purchased from Amazon "Vitamin C (L-ascorbic acid)"

Any help will be greatly appreciated... no matter how many times i try, the fogging is always there. So far i have only 1 clear plate with ony fog whatsoever. 1/30 plates so far is BAD!
jeff-blyth
Posts: 20
Joined: Sat Feb 18, 2017 9:41 am

Re: Homemade Plates

Post by jeff-blyth »

Dear Heferkimbo,
The fogging is due to not all the silver nitrate having been converted to AgCl in the dye bath in less than a minute. This is a chemical balancing act problem. A longer time in the dye / salt bath would have converted all the silver nitrate to the chloride but the grains would grow larger with that extra time in that sodium chloride solution and that would produce a scattery hologram later. Your gelatin coating is probably thicker in the areas where this fogging occurs and the diffusion of sodium chloride into those areas of the plate was not fast enough. I suppose that your gelatin may have given you a thicker coating than my gelatin did. So try diluting it by say 10% next time before your veil coating. If you have other plates that are already coated the same and waiting, then a much longer wash under running tap water is required after the dye/sodium chloride bath. This will get rid of any unconverted silver nitrate still in those thicker areas of the plate.( It is a pity to have to lose any silver like this of course). I don’t think the yellowing is a problem in the short term and it may indicate good photosensitivity. Have you made a hologram on those OK areas of plate yet? I would like to make sure that you do. My domain name is jeffinbath and I am “at” ntlworld.com. If you send me an email we can deal with any problems better.
jeff-blyth
Posts: 20
Joined: Sat Feb 18, 2017 9:41 am

Re: Homemade Plates

Post by jeff-blyth »

Hi Heferkimbo,
How did it go with your last tests? Please let me know. My username is jeffinbath for my email @ ntlworld.com. It is helpful to me to know what can occur when someone uses my system with some chemicals bought locally on the otherside of the world.
jeff-blyth
Posts: 20
Joined: Sat Feb 18, 2017 9:41 am

Re: Homemade Plates

Post by jeff-blyth »

I have had to do an update on the quality of silver nitrate purchased . It turns out that there is one really bad impurity that has to be as low as possible, and that is silver chloride (AgCl), otherwise you get bad grain growth and scatter. I have updated the recipe procedure to try to deal with this problem by keeping the stock silver nitrate solution in a refrigerator in a glass bottle. Please do not purchase a grade of silver nitrate if its chloride content is listed as "<0.01%". It needs to be more like "<0.0005%".
Heferkimbo
Posts: 16
Joined: Sun Mar 26, 2017 9:13 am

Re: Homemade Plates

Post by Heferkimbo »

I'm sorry for not answering sooner, but I completely forgot about this post.

I saw your updated instructions and unfortunately my AgNO3 isn't 5ppm. So I left it in a glass bottle inside the fridge as recommended and when using it with a syringe I will only take from the surface.

Recently I have been making some plates again, after my previous tests resulted in badly fogged plates. So far, I can get some "decent" looking and clean plates, with some minor black spots. I think I can avoid this in my next batch. Now there's a new issue... I tried to actually shoot some holograms and followed the steps described in your tutorial. My plates turn black in 15 seconds, so i wash them and put them in the bleach (reflection) for 1 min, they turn transparent (except some dark spots). Wash again and 3 minutes into the anti-printout. Leave to dry for an hour and the result are "milky" looking plates. All of my tests are the same. I even tried leaving the plate for 1 minutes in the developer (they turn very black) and clear with the bleach. But after everything is done, the result is the same: white, like fog. I used different plates with different exposure time up to 2 minutes.. to cover from under exposed to over exposed plates.

This plates had been kept in the fridge at 5Cfor at least 5 or 6 months I think, individually paced inside aluminum bags (the kind with a ziplock) and they are not translucent, so no light can damage them at least. SO I was thinking that my safe light, might be the cause? this is the one I got from amazon, similar to what you recommended. Below are some images of what the plates look like and the kind of light im using...is there a way to know for sure if the light is causing some of this issues??. EDIT: The plates look all scratched becase after the failed try I just stored them together.
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Grayham
Posts: 49
Joined: Wed Feb 11, 2015 12:56 pm
Location: Hampshire, UK

Re: Homemade Plates

Post by Grayham »

Below are some images of what the plates look like and the kind of light im using...is there a way to know for sure if the light is causing some of this issues??. EDIT: The plates look all scratched becase after the failed try I just stored them together.
[/quote]

To check your safe light get a CD and in the dark reflect the safe light off it and look at the diffraction and see if you can see any other colours. If you can then your light may be causing problems.
Secondly you can place a plate in developer under the safe light (without exposing) and see if it turns black. The CD method is cheaper :)

Are you also washing your plates in distilled water after you have made them and before you dry them to make sure you have removed all the salts?

I find if i leave an ascorbic acid sensitised plate for more than a couple of weeks it starts to fog.

Have you looked at another plate under normal light to see if it was already fogged to some degree?

Grayham
Heferkimbo
Posts: 16
Joined: Sun Mar 26, 2017 9:13 am

Re: Homemade Plates

Post by Heferkimbo »

Already did the disk test and the reflected safe light from my LED bulb on the surface of the disk (DVD is also ok right?) shows other colors. I can see blue and red, although they are not as strong as the reflected light when the LED has the white option selected. I thought something more dramatic would occur, like the plate turning black with unsafe light.

As for the washing of the plates, the answer is yes. I wash them with DI water in a small container, after that I spray them again with DI with a spray bottle.

I always watch the plates under my “safe light”.... the only time I looked at the plates under normal light was a few batches ago and they were “milky”... is that the same as foggy?. Perhaps I should use the plates the same week I make them and find a real safe LED light.

One more question... I am using small metal containers to both, make the plates and also for the developing stage. They are stainless steel containers, do they react with the chemicals?, should I start using plastic ones instead??.

Thank you for the help.

Edit: like this. Do they react with the chemicals?. Does anybody know?
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Jeff Blyth

Re: Homemade Plates

Post by Jeff Blyth »

Let’s try to get to the bottom of this.
You say “My plates turn black in 15 seconds, so I wash them and put them in the bleach (reflection) for 1 min…..”
Does this happen without any light exposure ? A bit of slightly unsafe safelight will not cause it to “turn black” , something else must be happening to get fogging on this scale. If the blackness is due to non-laser light fogging or chemical fogging then just bleaching it will cause plates to look like your photos . Can you just try to get a photographic image under laser light by putting some coins on top of the plate and beaming the spread beam down onto it. It should go black in developer only where the coins were not protecting it. If it all goes black then that means the plates are useless and something is very wrong. Stainless steel dishes cannot be the cause of it. Chemical fogging can be caused by long term exposure to for example low levels of formaldehyde. ( This has happened years ago when Agfa wrapped some of their plates in black paper which slowly released formaldeyde gas).
Grayham raised this interesting point that he observed “I find if I leave an ascorbic acid sensitised plate for more than a couple of weeks it starts to fog.” That suggests that the pH of the ascorbic acid sensitizer solution should be lowered to say maybe pH 4.0 by using less sodium hydroxide to your vit. C (this will decrease the photosensitivity somewhat). I am afraid that I have only sensitized my plates in tests in less than a week before exposure.
Jeff
Heferkimbo
Posts: 16
Joined: Sun Mar 26, 2017 9:13 am

Re: Homemade Plates

Post by Heferkimbo »

The light source is the laser when I tried to shoot the hologram. After I took them out of the aluminum bag, while the RGB Led light was on (green). They looked clear. This fogging appeared after all the steps to develop the plate.

Perhaps my plates are too old?. I will make a new batch of plates and use them within a week and make sure I test them first with your coin suggestion, to see if something else is causing it.

As for the stainless dishes, I was asking because in the book “Homemade Holograms” by John Lovine he mentions not to use metal trays because they react with the chemicals used for his developer and I thought that perhaps for your recipe they could cause something, not just the chemical fogging.
jeff-blyth
Posts: 20
Joined: Sat Feb 18, 2017 9:41 am

Re: Homemade Plates

Post by jeff-blyth »

Yes OK then, I will try to help when you have made some more plates and have more data . The plates should keep for many months if you don't treat them with the sensitizer or TEA soln. until you want to use them Although the bath containers are you say “stainless steel” , can you float one on top of the other to act as a lid to keep air out of the dev. for most of the time? Much cheaper transparent plastic ones that are tapered so that they fit into each other would be much better to use because you can check if your floating lid has not got an air layer between it and the developer solution surface. The developer will last for many hours only if you keep air off the surface most of the time. Lovine’s comment about metal trays reacting with the dev. is certainly true if they are aluminium but not in the case of stainless steel. However Stainless steel might just be attacked very slowly by the antiprint-out bath . I may be able to help you more quickly if you emailed me at the address I gave earlier in this thread.
Jeff
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