Selenium toning questions

[DAK]

Doremus,

Could you please explain how you replenish selenium toner?
Thanks,
DAK

 

[clayne]

It actually shift the image colour of the silver grains making them redder, and red/black acts more like a safelight filter when printing.

Ian

This isn't why it increases contrast however. The increase in contrast is directly related to expansion.

 

[Anscojohn]

Doremus,

Could you please explain how you replenish selenium toner?
Thanks,
DAK

***********
Doremus,

I would also be interested in this technique. And any hints on filtering used solutions, as well.

 

[clayne]

I personally have no rhyme or reason as to how I replenish selenium toner. I don't filter it either. I just let the black particles settle and never stir up or shake the solution. The floating selenide doesn't harm prints anyways. As far as replenishing I usually pour about 100ml or so of KRST into 1+20 after I feel toning is getting a bit long. This usually puts it somewhere back around 1+20 or close enough (I use 5000ml containers).

 

[Doremus Scudder]

For those interested, here's my technique of keeping a working solution of selenium toner going for a long time.

First, when toning times get too long, I simply add more concentrate. This rejuvenates the toner activity. It doesn't take very much concentrate to step things up, so use very little to start with till you get the feel of it. As you can see, like Clayne, I don't measure quantities here. If I get too short of toning times, I just dilute with water.

During a toning session, some of the toner gets carried over, diminishing the volume somewhat. At the end of the toning session, I top up the toner to the original volume with water.

I use coffee filters to filter the toning solution when pouring it back into storage bottles and when pouring it out into trays for use. This latter is where I get most of the black precipitate. My suspicion is that the silver carried over from the fixer and dissolved out into the toning solution in the form of thiosulfate compounds ends up getting toned and precipitating out of solution. I'm not sure about this, however. (Maybe one of the chemists here would care to comment?)

Originally, I was concerned that there would be a build-up of silver compounds in the toning solution due to carry-over. This does not seem to be the case; at least prints that I have treated in toner that I've had and replenished for years do not show elevated levels of residual silver. My guess (again, just a guess) is that the precipitate takes a the contaminates out of solution.

I keep two gallon bottles of toner, one at a relatively weak dilution and one a bit stronger; different papers require different strengths.

As I mentioned earlier, I like toning times of about 4-6 minutes. I like to see a little change in a minute or so. When these times are exceeded, that's when I add a bit of toner concentrate. Best is to dip a beaker of toner out of the tray, add concentrate and then pour back into the tray while mixing thoroughly. If you don't mix thoroughly, you can get areas of greater concentration in the tray for a while, which really wreaks havoc with a print ;-)

My original concern was with discarding selenium into the environment. My darkroom in Oregon is on a septic system that handles developer and stop alright, but I don't want to build up heavy metals in the system. (Used fix get taken to the local hazmat facility.) Dumping into the municipal sewer is suspect as well, as heavy metals do not get removed and collect in the sludge.

I do toss my toner once every few years, or at least parts of it. After a really long toning session, when times are getting long, I'll cycle scrap prints through the toner till no change in tone occurs after 15 minutes or so. Then I'll leave a few prints in the tray overnight. This ensures that the selenium is at a very low lever. I then mix this solution into my waste fixer jug and take to the hazmat center as well. I usually only do this every few years and then usually with just a couple of liters (i.e., half of my gallon jug).

JBlejer,

Since you have a lack of space, my work flow may be of interest to you. I divide my sessions into printing and toning, similar to how Ralph described. However, I give fix 2 during the toning session. Here's my sequence:

Printing Session: Develop, stop, fix 1, rinse/hold (at this stage I'll bleach if I need to as well), wash for 30 minutes minimum, dry.

Evaluation: I choose prints that I wish to tone. Often I make several versions of one print, so I cull out the non-keepers at this point. This cuts down the number of prints I have to tone.

Toning Session: Water pre-soak, fix 2 (alkaline or near-neutral pH fix; I am currently using Ilford Rapid Fix diluted 1+9 with no staining), toner (I transfer to toner without an intermediate rinse. If you use a more acid fixer, give the 10 minute rinse Ralph mentions), wash-aid, wash (I hypo-clear for 10 minutes and wash for one hour minimum).

As you can see, you don't need more than four trays out at any one time, saving space.

Hope this helps,

Doremus Scudder
www.DoremusScudder

 

[Ian Grant]

This isn't why it increases contrast however. The increase in contrast is directly related to expansion.

Of course its the reason for the expansion that increases the contrast, Uranium Intensifiers work in an even more vivid way but similar, converting the black silver image to a red Uranium image.

Ian

 

[RalphLambrecht]

...Originally, I was concerned that there would be a build-up of silver compounds in the toning solution due to carry-over. This does not seem to be the case; at least prints that I have treated in toner that I've had and replenished for years do not show elevated levels of residual silver...

Doremus

That's where a 10-minute wash between fixing and toning can help. You want to protect the toner from fixer carry-over. Not because of the hypo, there is hypo in some selenium toners, but because of the silver complexes in nearly exhausted fixer.

 

[RalphLambrecht]

Of course its the reason for the expansion that increases the contrast, Uranium Intensifiers work in an even more vivid way but similar, converting the black silver image to a red Uranium image.

Ian

Could it be that we have two compounding effects?

 

[Ian Grant]

With Uranium intensification the red toned negative looks less dense, but it has the opposite effect because the red Uranium is far more effective at filtering out the blue end of the spectrum so the contrast is greatly increased. In simplified terms the silver grains are like an ND filter allowing some light, whereas the Uranium grains are more like a Safelight filter.

Selenium toning adds red selenium initially to the silver image, left long enough the silver is replaced by red- brown Selenium. So initial Dmax goes up then drops with time but as it drops it's far redder so more effective.

Ian

 

[RalphLambrecht]

With Uranium intensification the red toned negative looks less dense, but it has the opposite effect because the red Uranium is far more effective at filtering out the blue end of the spectrum so the contrast is greatly increased. In simplified terms the silver grains are like an ND filter allowing some light, whereas the Uranium grains are more like a Safelight filter.

Selenium toning adds red selenium initially to the silver image, left long enough the silver is replaced by red- brown Selenium. So initial Dmax goes up then drops with time but as it drops it's far redder so more effective.

Ian

Ian

That's one effect and not disputed, but there also is a simple increase optical density as measured with a densitometer. Both effects are working together when the negative is projected. An increase in 'red' density is more effective than any of the two alone.

 

[Ian Grant]

Ian

That's one effect and not disputed, but there also is a simple increase optical density as measured with a densitometer.

Selenium toning adds red selenium initially to the silver image, left long enough the silver is replaced by red- brown Selenium.

There's a point when the overall optical density reduces again, which happens faster with prints but also happens with negatives. The Red channel is increasing though.

Ian

 

[RalphLambrecht]

There's a point when the overall optical density reduces again, which happens faster with prints but also happens with negatives. The Red channel is increasing though.

Ian

Ian

Selenium toning first increases density but some of it can be lost with prolonged toning, but I've never seen negative or print density to be lower after toning. The color change is certainly part of the contrast increase, but there are two forces at work, not just one.

 

[Ian Grant]

Ian

Selenium toning first increases density but some of it can be lost with prolonged toning, but I've never seen negative or print density to be lower after toning. The color change is certainly part of the contrast increase, but there are two forces at work, not just one.

Then you've never split toned or completely toned a print in Selenium toner, the drop in density is similar to sepia toning. It can happen with negatives as well as most people use KRST at 1+2 for negative intensification.

Ian

 

[RalphLambrecht]

Then you've never split toned or completely toned a print in Selenium toner, the drop in density is similar to sepia toning. It can happen with negatives as well as most people use KRST at 1+2 for negative intensification.

Ian

Ian

I certainly have done all of that, but I've never toned anything in KRST 1+2.

 

[naugastyle]

I dont particularly care to change the print, I like the way they are coming out

You will like them better, almost guaranteed. MGIV 1:20 is very subtle and there shouldn't be any purplish color shift...but it will take away the green tint of the blacks. It doesn't look green until you compare a toned print against an untoned one.