I think tkamiya's test was a good one.
I recall the most archival toner is sulfide... but I don't want that look... I am happy to "contribute towards image permanence", without worrying about exactly how many centuries we're talking.
But if you really want permanence, by all means do a test like tkamiya's - it will tell you how well you are doing.
Oh, by the way....
There is a product called SISTAN that can be used to help permanence of the image. There was AG Stab which doesn't seem to be available anymore and Adostab that is basically a replacement, according to FreeStyle.
This is NOT a toner. It doesn't change color at all. With AG Stab, I didn't notice the darkening of the image in the item description. Use this as the last step after wash and squeegee off the excess and let dry. What I understand is that an active ingredient in these products protect the silver from degrading. I've used it few times.
If image permanence is really an important concern, you may want to check into these as well. If you are printing something like a family portrait, it may be important that grand children can show their grand children what their parents looked like.
tkamiya, thanks for all the info. Sounds like a good idea to try and do that test!
My understanding is that gold toner does inevitably alter look and in the U.K. 1L which might do 50 8x10 prints cost about $80!!!
The real longevity toner is the brown sulphide one. Much cheaper than gold and probably better than selenium but it will change the colour of your print.
Sistan doesn't change colour but by how much does it increase longevity?
Key to all this in terms of cost to benefit is how long do you need the prints to last? So far it seems that properly processed and washed prints, even RC, have now lasted about 30 years and FB a lot longer
Toning to completion means full color shift. This will vary depending upon paper. If you do not want color shift, or as little as possible, then "permanence" may be compromised (however defined or desired). Toning to color shift in terms of timing, which may increase contrast and "sharpen" the image, is somewhat a matter of trial and error, depending on:
Originally Posted by Carina
- paper type
- toner dilution
- degree of toner exhaustion
I use selenium toner for minimal color shift. I normally do this with all prints at the end of the day. One needs to watch the first toned print for a color change, whereupon it is quickly withdrawn, taking note of the time. The rest (same paper) can be batched at the noted time. I have noticed, in my lab, that the time to color shift increases by approximately 30 seconds, each day as toner sits around and becomes both exhausted and/or oxidized. I toss it when toning times become too lengthy and then mix fresh (KRST –> 1:20).
20 years for a c-print ? you are very optimistic...
Originally Posted by litody
The safest way to have a print toned to completion is to split tone. Either in selenium & various sulfide or selenium & gold. That way you can get the color of your choice.
I agree - I only tone for color shift - just did some prints on Slavich Bromoportrait 80 - a lovely warmtone double-weight baryt fiber paper.
My wife wanted them sepia to match a room decor (heck, I'll do anything to get my wife to hand more of my crud).
I used KRST 1:9. I toned immediately after washing - strong color shift tosepia in aboyt 90 secs - completed teh color I wanted at 1:30.
If you are concerned that much with permanence your question should be about washing, not toning. You could tone to your hearts content but if the print isn't washed appropriately it will go south.
IMO toning should be done for the look it gives. The secondary effect of toning is longevity. If you wash the print appropriately, even without toning it, you will be long gone before any problems arise.
It's hard to say, and it varies with the toner. As a rule, use the long end of the range recommended by the manufacturer. Many toners slow down but continue to tone for hours. That is overkill. Half again longer than when you stop seeing obvious changes is more than enough. With some gold toners, like GP-1, you may not see any changes at all. With those, use the manufacturer's recommendations as a guide. If you are toning multiple prints in the same bath, remember that toning slows down as the bath is used and becomes more exhausted. You need more time for the same results.