I have tried "crazy" stuff like this... something always turns out "thin" or "overcooked"... Images taken arn't worth the risks of this sort of thing.
What I HAVE done and it has obvious risks is add a rool wound on a reel "later" to the mix, I agree if things are in the ballpark and it's photojournalism deadline time do it (as I have) otherwise it is a false economy to do this on a basis of cost.... the economies of time are another story.
I have done this when I have a couple rolls that are being "pushed" with a couple rolls normal, the hazzaards of fogging the film or mixing up the pour in the dark are issues too.
One way to deal with this is to put the developer in the tank before loading. Load the reels, put the one in that needs more time, and start the timer. Put the second reel in at its time put the lid on, turn on the lights and continue.
Just make sure you can keep track of what's what in the dark.
if each has about 1 minute difference, then why not split to the half for each? I mean for 11min film make it 11.5min, and for that 12min make ir 11.5min, so it is like one is a bit 30sec overdeveloped and the other is 30sec underdeveloped.
I never find the optimal time for most of these "mixes" to really be a minute appart...
Again... I think some of the folks chiming in have never DONE it. I have and I posted my impression of REAL results.
APUG makes me nuts with folks guessing about stuff that they have no experiance with.
That massive dev chart is like the Wikipedia of processing. I have doubts about real testing and situations. For ME I have always found HP5 to be an ISO 250 film if developed by the ilford chart... and that's from Ilford, not some Wiki developemt chart.
This is a great forum with active, helpful people. I'm sure glad I joined.
Thanks again for the ideas. These two rolls aren't *that* important but I'm leaning toward the idea of putting the longer-timed one in first, then after a minute, put in the other. :-)
My first post just stated what one "should" do. What I probably would do (and have done!) is probably develop both at the same time, using the longer time if the scenes photographed have normal contrast, and the shorter time if the the scenes were of slightly higher than normal contrast. What is important is how the negatives print . By keeping notes on the time, temperature and agitation method, you'll be able to better determine the time that you should use the next time you develop these films, together or separately (when photographing similar contrast ranges in the scenes).
If you find you are needing a 3 filter or higher for most of the negatives, then you will want to increase your development time to increase the contrast of the negatives. If you are needing a filter lower than 2 all the time, then decrease the dev time to decrease the contrast of the negative. Use the strength of the shadow detail to determine if you are exposing well.
All this is instead of doing exposure/development tests -- which are not a bad idea at all...just one I have refrained from doing these past 30 years or so...;)
i would do each roll separately the first time
find out what time/temp/ combo worked best for each roll
and if they were the same the 2nd time i would do them together
if not ... its not worth negatives that don't turn out the way you want them.
you exposed the film, the exposures must mean something .... why waste them with bad processing ...
A funny combination I shoot from time to time is FP4+ @200 and Delta 3200 @3200 which I develop @6400. In DD-X 1+4, the FP4+ @200 is 12:00 while the Delta 3200 @6400 is 12:30 and I find the :30 is not that critical for the FP4+ after 12 minutes so I develop both for 12:30 and they turn out great. Just odd that one is 200 and the other 6400 EI in the same tank for the same time! Delta 100 @100 is 12:00 so I can toss that in too. HP5+ @1600 is 13:00 so OK to do with the Delta 3200 at least ;)
Diafine. Same times for all films - well some want a minute more but that minute will make no difference in those that are "done" sooner. You'd have to experiment to find the right exposure index for each film though. It likely will not be box speed.
Surely it's of no importance as long as contributors make it plain whether their comment is a considered opinion or based on first hand experience?
Originally Posted by vpwphoto
Though I've never personally shoved my hand into a vat of boiling acid, I'm sure you'd agree with my supposition that it would hurt a bit and wouldn't do me any good!