Depends upon the paper and your desires.

I've realized a deeper black with Agfa MCP and MCC and like the look alot.
Looked OK on Cache FB Plus and on Ilford MG IV RC was stunning.  This is in
addition to the archival qualities it imparts on the print as well.  I think
it's worth it for the extended life it gives the print alone.

KRST is not the cheapest chemical on the dealer's shelf, but it won't break
the bank either.  Might I suggest you buy a bottle and give it a try.  If
you are really skeptical, tone one of your work prints first and see what
the result is.  It may convince you right there.  I've ended up with work
print looking better than what I thought was a good final after dunking it
in KRST (did this to make sure it was still good).

Hi Mike,

A year or two ago, I posted in this newsgroup a chart of what effects
Selenium has on what papers given various developers.  You may want to
look it up.  Some papers do not change color, some have radical changes.

A study of increase in contrast was published in Photo Techniques USA a
couple years ago.  It found that for the maximum increase in contrast, 2
- 4 minutes in selenium is desireable, and that after that there is a
slight drop off from the gains achieved.  For some papers, a  tonal
shift will already have started by 4 minutes, however.  You have to know
which is which.

Another consideration is archivability.  It is generally accepted that
2-4 minutes in a 1:9 solution of KRST does not give full protection to a
paper.  For that 10-11 minutes is probably needed.  Even at that, it
seems that some protection that used to be achievable with KRST is now
longer available because "contaminants" are no longer in the KRST.  The
"contaminants" turned out to be the principal ingredient in Kodak Brown
Toner.  This leads to the interesting possibility of intentionally
contaminating your KRST with  minute amount of Brown Toner - just enough
that some protective effect is had, but not enough to affect tonality in
a 2-4 minute bath.

Francis A. Miniter

Its effect depends on the dilution, paper,  and the amount of time you leave
the print in the solution.  Higher dilutions (1:20 or greater) have little or
no effect on D-max and are used to make the silvered image more permanent.
Lower dilutions (1:5 or less, usually,) can have an effect on D-max and/or
image color, but it depends on the paper.  Since you use it in light, keep an
eye on the print and pull it when you get the effect you like.  Keeping an
identical reference print (wet) to compare it to can be of some help in judging
the changes that have occurred.

Obviously, all the above are generalities:  your mileage may vary.  Experiment
and have fun!

mjs
<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>
C program run.  C program crash.  C programmer quit.
<<<<<<<<<<<<<<<<<<<