New to Wet plates need help

[Film Photographer]

Hello All

As the title reads I am very new to wet plates specifically tintypes. I am having issues with my silver nitrate bath. I tried to prepare a one litre solution with a specific gravity of 1.069 and it read correct in the hydrometer. When it came to PH reading I was lost did not know how to read the PH strips and also have a digital meter for this it initially showed a value of 10 which did not make sense. So I added some glacial acidic acid I added a lot of it obviously it was mistake. I dropped a plate overnight as suggested and I coated a plate in the morning and dipped it in silver nitrate for 4 mins and then exposed it for 45 seconds as suggested by the light meter I was using some artificial light. I then developed it using the developer and I could not see any image the plate itself looked murky and could see spots of silver.

How can I fix my bath should I add water to dilute the acid and need to know how to read the PH strips I have one which reads 1 to 14

 

[TheMissingLink]

G'day,

you are facing the usual beginners problems ;-)

First don't waste you silver bath, you can try to rescue it:

If you are using test strips for ph you probably have them out of a booklet. Every single strip is usually only used once. On the back of or inside the booklet you should find instructions and a color table to compare the wet strips. If not in yours toss it and buy a new and complete one for only a few bucks. I personally trust electronics ;-)
If you have too old strips they can show you wrong values. The right ph should be 4-5 for your ambrotypes, around 6 for negatives.
Too rescue you bath add carefully sodium bicarbonate until you reach the desired ph. At this point the bath isn't usable for a short time due to chemical reactions, let it rest until it's clear again.

Don't trust your light meter! It measures at specific wave lengths and not necessarily the lengths YOU need for WP. On the other hand, which artifical light source did you use? Remember WP is blind(er) for the low side of the spectrum.

Your plate is murky? How much? 42? ;-) There are some possible reasons for it: Your bath, your collodion, duration of exposure ...

How old is your colldion? Self prepared or readily mixed? Could it ripen? Which one? Your developer?

First try to rescue your bath, filter it after clearing, measure to 1,07 and your desired ph.

Next analyse your light ...

Always only change ONE variable and try to be sure of it before doing the next change, this is very important!


hth

horst

 

[Film Photographer]

Thanks for the reply I will check the bath again and try and salvage it I am using a light tent and use around 300 watts of strobe lights thanks again for the advice I maybe under exposing the plates but first I need to fix the silver bath

Just one question what do I do if the bath is very acidic like 2

 

[TheMissingLink]

You had initially a ph of 10 you wrote than it should have been alkaline like soap. You added "some" glacial acidic acid and it went ... somewhere.

Perhaps you use too much acid or not enough. If you now (with new stripes or a calibrated electronic infernal stuff) measure a value too low you probably got a too acetous soulution (< desired value). With the above mentioned Sodium Bicarbonate you are able to partially neutralize the added acid,moving the ph-value up the scale again.

But: It doesn't work again and again ... changing the ph with acid and neutralizing it should stay an exception ...

horst

 

[Film Photographer]

Thanks for all the help Horst appreciated will keep you posted I also have contacted some chemical companies here is Australia if they can make a 500 ml batch with my specification sand have agreed to do that. I guess to start with I can use that solution and this will help me check the PH using the meter I have and will be able to maintain it after that....

 

[noofy]

I really recommend not interfering with the solution too much... I have worked with my solutions for 4 years and only maintained them by sunning and topping up with silver nitrate as necessary. It just works!

 

[Film Photographer]

Thanks for the advice appreciate it