How much benzo to combat fog?

[naaldvoerder]

I am trying to save my remaining stockpile of Forte Polywarmtone. I went a little overboard, when Forte's demise was announced. I use benzo to try to prevent the fog. My question is up to what concentration of benzo is sane to use? Are there other measures to along with it? Reducing development time? Increase contrast setting? Bleach back?

I know I can use it for lith, and I know I should get new paper. I just eagerly await Adox efforts..

I have been doing test with up to 40cc of a 1% solution benzo in 1 liter of developer. There is still a small veil visible.

 

[Patrick Robert James]

It will depend on the developer in my experience. I prefer to use really strong developers so if I am using old paper sometimes I have to add quite a bit. Eventually the developing time will get so long it isn't worth it. Personally I will add BZT until the fog is gone or the developing time reaches 7 minutes. At that point it isn't worth it anymore and the paper goes in the fogged pile.

You can also change developers. Some developers are better for old materials than others. I was using E-72 and other Ascorbate type developers for years trying to stay "eco" friendly. They were crap. I went back to Neutol WA.

if you are going for a real warm tone you can overexpose and pull the print early. That will reduce fog somewhat and give you warmer tones.

If you have any of the purple label you probably won't have any fog. The yellow label was the one that was reformulated (IIRC). Mine has seen better days and it is in the fogged pile now. Sad. Polywarmtone from the 90s was one of the best papers ever. Gorgeous stuff.

 

[newcan1]

I have found that more than 2g/L (which is a LOT) is counterproductive. If the paper is badly fogged, use enough to cut the fog to a light grey and bleach back the remainder after development. Or, I have found that badly fogged Forte paper (not warmtone, because I have not tried that) does really well when pre-treated in a rehalogenating bleach, although it loses speed and is no longer multigrade. A nice, bright grade 2 or 2.5 though. I have some outstanding results using this method on Forte paper so badly fogged (probably about 20% grey) that it was otherwise unusable.

While time consuming, I like the rehalogenating process. I have found that when MG paper is badly fogged, it tends to lose its multigrade status when using bzt anyway. Bzt seems to retard development rather than eliminating fog, so what you are really doing is over-exposing and controlling development rather than truly eliminating fog. My best results by far have been through pre-treating the paper in a ferri/bromide bleach, rinsing and drying (all in dark/safelight) before use, then using as grade 2. The Forte paper I have doesn't lose as much speed as some others, and it produces a nice long grey scale with deep blacks.

 

[naaldvoerder]

I have found that more than 2g/L (which is a LOT) is counterproductive. If the paper is badly fogged, use enough to cut the fog to a light grey and bleach back the remainder after development. Or, I have found that badly fogged Forte paper (not warmtone, because I have not tried that) does really well when pre-treated in a rehalogenating bleach, although it loses speed and is no longer multigrade. A nice, bright grade 2 or 2.5 though. I have some outstanding results using this method on Forte paper so badly fogged (probably about 20% grey) that it was otherwise unusable.

While time consuming, I like the rehalogenating process. I have found that when MG paper is badly fogged, it tends to lose its multigrade status when using bzt anyway. Bzt seems to retard development rather than eliminating fog, so what you are really doing is over-exposing and controlling development rather than truly eliminating fog. My best results by far have been through pre-treating the paper in a ferri/bromide bleach, rinsing and drying (all in dark/safelight) before use, then using as grade 2. The Forte paper I have doesn't lose as much speed as some others, and it produces a nice long grey scale with deep blacks.

Do you do this with FB paper? Must be a pain to get it to dry to a workable flatness to put it on the easel again. Do you treat whole boxes of paper like that?

 

[M Carter]

While lith is a solution, it's not for everybody, and for images with really smooth tonality it can be difficult to fight the grit. But it can be miraculous with heavily fogged paper. And PWT in aging developer can get some really flaming colors (which can be brought back down controllably).

But I've had some success with exposing with the fog in mind, and then bleaching back, even with spot bleaching. Cleaning borders with ferri/fix and a good brush.

You can also develop the print, bleach back the highs and upper mids, and re-develop in very dilute standard developer, which gives you a lot of control. Having a 2nd bath of just water and a tray of stop bath helps, as it becomes a snatch-point issue. So slowing things down in water and going straight to acid stop can help find the sweet spot. Follow that with spot bleaching, farmer's overall, selenium - whatever it takes. I like this since I've had terrible success retaining highlights with variable sepia toner. I've also found (with the papers I've tested) it can have the "look" of sepia, deep warm chocolatey browns - weak selenium can ease off the warmtones and push things into charcoal territory though. It can get process-intensive, so you have to have that level of geekiness/patience.

 

[naaldvoerder]

Thanks for the info! What is the benefit of doing the bleaching back in ferri and fix combined? Instead of bleaching with ferri first and then fixing?

 

[newcan1]

Do you do this with FB paper? Must be a pain to get it to dry to a workable flatness to put it on the easel again. Do you treat whole boxes of paper like that?

I do about ten sheets at a time. It is a pain and I could get a higher hourly rate flipping burgers. But I feel the knowledge and the process help make me better in the darkroom. You start thinking about printing a little differently. (Like, "a little bleach back would really make those highlights pop".) I have a little regime going for the rehal'ed paper, I always use ID-14 as the print developer for it, I would never have thought of that if I hadn't gotten into this journey with old paper. One day I will post some results.

 

[newcan1]

Thanks for the info! What is the benefit of doing the bleaching back in ferri and fix combined? Instead of bleaching with ferri first and then fixing?

I bleach first then re-fix. I guess doing the farmer's reducer thing helps you see the bleached results better in real time, as excess halides are removed at the same time. But I will bleach a little then rinse and fix a little, to see incremental results. That way there is a reduced risk of over-bleaching.

 

[Gerald C Koch]

Benzotriazole is useful for slightly fogged paper but it is not a miracle worker. Image tone and paper speed will be affected. If adding a small amount of BZT then it is best to ditch the paper. Add it in 00.5 g increments. If the fog still persists after adding 2 to 4 grams per liter of working strength developer then the paper really is beyond help.