Reading Photographers Formulary Residual Hypo Test on papers

hoffy · Nov 6, 2017

Hi Folks,

I have just recently tried the Photographers Formulary Residual Hypo Test for the first time on a freshly washed Ilford FB print. I followed the instructions with the test.

Initially, I thought there was a very slight stain, but I blotted the spot again and couldn't see the stain at all. Is this now a false reading?

Also, while I understand their test is only an indication, there instructions are very loose. I have the book "Beyond Monochrome". If I was to use the guide in the book, would this be a good enough indication?

Cheers

Fraunhofer · Nov 6, 2017

Very slight stain is per instruction okay anyway and the test solution itself has a yellow tinge. If there is no or only a very slight stain after blotting you're good.

hoffy · Nov 6, 2017

OK, that is what I was thinking. I was under the impression that the paper is stained, but it just went a bit weird - I.E., an apparent stain to no stain!

Doremus Scudder · Nov 7, 2017

Originally, Kodak sold a "Hypo Estimator" strip of colored patches that one would compare the stain to. I don't know if they are still available new. There is a (downloadable) image of one on Ed Buffaloe's Unblinking Eye site: https://unblinkingeye.com/Articles/Archival/archival.html

Best,

Doremus

hoffy · Nov 7, 2017

Doremus Scudder said:
Originally, Kodak sold a "Hypo Estimator" strip of colored patches that one would compare the stain to. I don't know if they are still available new. There is a (downloadable) image of one on Ed Buffaloe's Unblinking Eye site: https://unblinkingeye.com/Articles/Archival/archival.html

Best,

Doremus

Thanks for that. I had never read that one before. Curious to see that he is washing for a long time after toning! Might be worth another thread in itself.

Cheers

Doremus Scudder · Nov 8, 2017

hoffy said:
Thanks for that. I had never read that one before. Curious to see that he is washing for a long time after toning! Might be worth another thread in itself.
Cheers

I think that the two-hour wash time mentioned is a bit longer than necessary. That said, I wash for 60 minutes after toning and a wash-aid bath. The real proof of the pudding, and the confirmation of your workflow, are the residual hypo and silver test results. The Formulary hypo-test kit is basically the Kodak HT-2 test. The Kodak residual silver test, ST-1, is really easy to mix, but doesn't last long. Selenium toner can be used for testing residual silver as well, and I find it more convenient. My prints pass both tests with 60+ minutes of washing.

Best,

Doremus

hoffy · Nov 8, 2017

How do you use selenium to test for retained silver?

Doremus Scudder · Nov 9, 2017

Using Kodak Rapid Selenium Toner as a Residual-Silver Test

Kodak Rapid Selenium Toner 1+9 with water (according to Tech Pub. J-1, 1973, p.41. Undiluted KRST may be better; see link below.)

1. Place a drop of the diluted solution on a squeegeed, white margin of a print or a clear part of film.

2. Wait two to three minutes; then wipe off the drop with a clean blotter or cloth. Any discoloration other than a slight cream tint indicates the presence of silver. Refix.

There's more info at (there was a url link here which no longer exists)

Edit: GRRR! It seems the old apug links don't work on phototrio! Annoying to the max. I'll start a thread about this.

Best,

Doremus

hoffy · Nov 9, 2017

Thanks! Today I've learnt something new!

bdial · Nov 9, 2017

The Kodak Darkroom dataguide books have a hypo test color chart, they also discuss silver testing with ST-1 and Selenium.

hoffy · Nov 17, 2017

Hey folks,

I'm going to dig back into this thread again. When I did the test on the wet prints, I followed the instructions - wiped the wet print, put a drop on, waited 2 minutes and blotted. On the day and at that time, I noticed that there was no stain.

Two weeks later, I have come back to the now thoroughly dried prints and notice that there is indeed a plum (not cream) stain where I put the drop of test solution. What does this indicate? Is this insufficiently washed? Can I now re-wash the prints again?

Cheers

Anon Ymous · Nov 18, 2017

No worries, it doesn't indicate anything. Take a piece of plain paper and put a drop of the solution on it. Leave it there and sure enough, there will be the spot you describe. What matters is the spot, if any, formed within the few minutes. BTW, rinsing the print after the test will reduce the intensity of the spot considerably.

hoffy · Nov 18, 2017

OK, thanks. I did some reading after posting here and came to that conclusion. I also tested my printing again today and they appear to come up with no noticeable spot, so I am relatively happy with my process*

*Yes, I understand that this is not a definitive test....

Gerald C Koch · Nov 18, 2017

It's not the formation of a spot but the darkness of it. Anything other than a barely discernable spot is a positive test. Kodak in the Darkroom Guides had color swatches which one matched to see just how bad the result was.

hoffy · Nov 18, 2017

Yes, I understand that. When I follow the instructions and wait the two minutes, there is no stain. But, after leaving the print for a while, the spot darkens.

Reading Photographers Formulary Residual Hypo Test on papers

Privacy & Transparency

Privacy & Transparency