Salted paper problem: staining after toning

Hello, this is my first post here, so I want to thank everyone for the incredible amount of knowledge you have shared.

I'm new to salt printing, I started less than a year ago and now I'm having problems with staining after toning.

Here is my process in detail, please help me find where the problem may be.

1. Paper Hahnemühe Platinum Rag, 2 x 170mg with 2.5% ammonium chloride and 2.5% citric acid (2x means, I double coated both the salt and silver nitrate)
2. Sensitising: 2 x 170mg 15% silver nitrate.
3. I used a digital negative, without a developed correction curve, so the tones on the strips are uneven. My aim with them was to achieve the deepest black and paper white.
4. I exposed it for 35 minutes in my DIY UV box, which uses UV LED strips (wavelength 395 nm - 405 nm).
5. After the exposure I gave it a 6x1 min wash with tap water.
6. Followed by 4 min 5% salt wash (fresh solution, additive free kitchen salt).
7. Again 4 (+n) min wash in tap water
8. Toning with Möersch MT10 thiourea gold toner (see picture for toning time). The toner was new, not used up, the tray wash was very clean, only used for toning.
(Note: As toning was done one by one, the strips were floating in the tap water for more than 4 minutes before and after toning, see points 7 and 9).
9. 4 (+n) min washing in tap water
10. 4 min of 5% washing in fresh 5% salt solution
11. 4 min fixer (15% sodium thiosulphate, 0.2% sodium carbonate. The fixer was made 2 weeks ago, but I'm sure it's not exhausted, I just fixed some test strips in it earlier).
12. Another 4 min fixer
13. Another 4 min wash in tap water
14. 4 min hypoclear wash (1% sodium sulphite solution, made 2 weeks ago).
15. 6x5 min wash in tap water (2 tray wash)
16. 2x15 min tap water wash (2 tray wash)

The problem is that I got yellow discoloration on the toned stripes. What's interesting is that the more toning time, the less staining. (I've increased the saturation in the pictures to make the staining more visible).

I have a few ideas on how to solve my problem (use TF-3 fixer for less time, check the Ph of the tap water, increase the toning time), but I would really appreciate any suggestions on what to do and what could be the cause of this yellowish staining.

Thank you in advance!

István

I know nothing about salt print technique specifically but toning before fixing strikes me as odd, is that the right order?

grain elevator said:

I know nothing about salt print technique specifically but toning before fixing strikes me as odd, is that the right order?

Click to expand...

Yes, in salt printing there are prior to fix toning formulas. Christina Z Anderson wrote: "Gold and platinum toning comes _before_ fixing, because toning produces photosensitive silver chloride which needs to be fixed out, more important, it avoids sulfiding the print and making it more prone to fading."

Hi, Welcome to Photrio!

Looks like you have a overall blue cast in your image. Is it possible to remove that? it will make the yellow stain more visible. I don't know if this is from a scan or a camera - you can use a known grey card if you have one to correct the white balance.

:Niranjan.

nmp said:

Hi, Welcome to Photrio!

Looks like you have a overall blue cast in your image. Is it possible to remove that? it will make the yellow stain more visible. I don't know if this is from a scan or a camera - you can use a known grey card if you have one to correct the white balance.

:Niranjan.

Click to expand...

Hello, you are absolutely right, there is a blue cast, I will shoot another image with the correct white balance, as soon as possible.
Thanks, for pointing this out!

Here are 2 images with the correct white balance (made with Nikon d750 using a grey card).
The second one I made to be oversaturated to make it easier to see the discoloration.

View attachment DSC_3369.jpeg

View attachment DSC_3369-oversaturated.jpeg

Istvan said:

Here are 2 images with the correct white balance (made with Nikon d750 using a grey card).
The second one I made to be oversaturated to make it easier to see the discoloration.

View attachment 316623

View attachment 316624

Click to expand...

Yes, much better now. Thanks.

I don't have an explanation of why this is happening, but as you already pointed out, it seems to be coincidental with less than optimum toning with the full toning seemingly not achieved before 12 minutes - if you go by the tone in the shadows. So unless you are looking to do partial toning, this wouldn't be an issue. But it's curious though. Normally you wouldn't notice this unless you do a systematic time-tone study like what you are doing. Most people just tone to completion, i.e. until it makes no further change visually in the tray.

:Niranjan.

I never had much luck with toning before fixing with salt prints. There was always staining; the extent varied, but it was always there. Just fix before toning and the problem should go away if the remainder of the processing is good.
Be careful with darkroom lights; as soon as the silver nitrate hits the paper, any light source even with a small uv component will fog. Don't be fooled by how slow salted paper is; it still fogs, sometimes badly, if a little (or a lot) UV is present in your workspace.

PS if you don't mask your prints you can never really tell if your process is any good in terms of fogging or staining. At least during testing I'd recommend making a part of the print (typically a border) with rubylith or perhaps tinfoil to check if your masked areas remain paper white without any visible tone after processing and exposing the finished print to daylight.

nmp said:

Yes, much better now. Thanks.

I don't have an explanation of why this is happening, but as you already pointed out, it seems to be coincidental with less than optimum toning with the full toning seemingly not achieved before 12 minutes - if you go by the tone in the shadows. So unless you are looking to do partial toning, this wouldn't be an issue. But it's curious though. Normally you wouldn't notice this unless you do a systematic time-tone study like what you are doing. Most people just tone to completion, i.e. until it makes no further change visually in the tray.

:Niranjan.

Click to expand...

Thank you very much for the practical approach, I honestly felt very stuck on this issue, but you are definitely right, I can move on without resolving the issue if I don't want a time-tone study at this point.

But of course, I'd still like to know where this staining is coming from, mainly because of these reasons: 1. It can affect the archivability of prints (who knows, maybe only fully toned strips are slower to blur), 2. It's common practice in salt printing to achieve different colours by partial toning.

Thanks again for the practical approach!

koraks said:

I never had much luck with toning before fixing with salt prints. There was always staining; the extent varied, but it was always there. Just fix before toning and the problem should go away if the remainder of the processing is good.
Be careful with darkroom lights; as soon as the silver nitrate hits the paper, any light source even with a small uv component will fog. Don't be fooled by how slow salted paper is; it still fogs, sometimes badly, if a little (or a lot) UV is present in your workspace.

PS if you don't mask your prints you can never really tell if your process is any good in terms of fogging or staining. At least during testing I'd recommend making a part of the print (typically a border) with rubylith or perhaps tinfoil to check if your masked areas remain paper white without any visible tone after processing and exposing the finished print to daylight.

Click to expand...

Thank you for sharing your thoughts! I understand you do the gold toning _after_ the fixing? I thought that was a big no-no!

As for the lights, I work with a red safe light and I strongly believe the staining is from the toning because the untoned strip is not stained.

I very much agree with you on the need for a test area with true paper white. I usually mask my prints and on these test strips the top white area is not sensitized.

Can you briefly share your process, pls, so I can try gold toning after fixation, please?

Istvan said:

Thank you very much for the practical approach, I honestly felt very stuck on this issue, but you are definitely right, I can move on without resolving the issue if I don't want a time-tone study at this point.

But of course, I'd still like to know where this staining is coming from, mainly because of these reasons: 1. It can affect the archivability of prints (who knows, maybe only fully toned strips are slower to blur), 2. It's common practice in salt printing to achieve different colours by partial toning.

Thanks again for the practical approach!

Click to expand...

Since gold toning is a replacement process, partial toning will still leave bare silver on the print which will still be amenable to stability issues, just like an un-toned print. So, if stability is of importance, I would do complete toning with gold, unless followed up with an another toner like palladium or sulfide etc to finish the job. Of course, stability in salt print, first and foremost, is dependent on how well it is fixed and how good washing is to remove the fixer from the paper. Even without toning, if these two are done properly, the print should stay good for a long time.

:Niranjan.

Istvan said:

As for the lights, I work with a red safe light and I strongly believe the staining is from the toning because the untoned strip is not stained.

Click to expand...

I would tend to agree with this from the test strips shown above - the 1st step is fairly close to paper white - so staining related to untoward exposure or chemical interaction with the paper does not seem to be a problem of any significant degree here.

:Niranjan.

Istvan said:

I understand you do the gold toning _after_ the fixing? I thought that was a big no-no!

Click to expand...

I wouldn't see why! Truth be told, it's easier to get a really deep neutral to purple tone when gold toning before fixing and tones may end up a bit warmer if it's done after fixing. But the staining issue wasn't worth it for me.

My process is just salt printing, fixing, rinse a couple of times and then gold tone to the desired point. Then wash thoroughly. I have a YouTube video on it somewhere; just search for "Koraks salted paper print" on youtube and it should pop up.