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Discussion in 'B&W: Film, Paper, Chemistry' started by Markok765, Oct 17, 2006.
What are the diffrences between 1:25,1:50 and 1:100?
What one is the best?
I am using tri-x in 35mm
I did a test with 4x5 FP4+ and didn't see a great difference. I would think that with a smaller format the differences would be greater, and perhaps with different film you would also get somewhat different results.
One difference is economy. With higher dilutions, you will be getting more mileage out of the dev.
Another reason for diluting is to help contol contrast in the the negative; the highlights will be more under control.
"ORWO Formulae" had this to say about Rodinal (R09) dilution:
"Little diluted" would mean lower water + concentrate solutions. "Speed utilization stands provided that developing time...." would mean that the exposure index/ISO/film speed of the film can be used as published when developing times are extended (perhaps up to 50%) when developing in highly diluted (1+100 and up) solutions.
High dilutions give compensating effects, "tamed" highlights, finer grain, extra perceived sharpness and usually, lower emulsion speeds. At 1+40 or 1+50, the film speed remains quite constant.
I have found that the best overall dilution for Rodinal to be 1:50. For Calbe R09, which is a bit weaker the ratio would be 1:40. I would consider 1:100 to be the practical limit. Past this point one risks the chance of exagerated edge effects which can be visually rather unpleasant.
Of course, dilution also determines the developing time which can be excessive with higher dilutions.
How do you agitate, I just twist about once every 5 mins 1:100? After 20 mins or so I empty fill with water and leave another 5-10 mins.
Even at 1:100 I give one gentle inversion every minute. If the film sits for too long without agitation you also get the exaggerated edge effects. While edge effects can increase the perception of sharpness in a print, once they become readily apparent to the eye the advantage is negated.
i have just used panf in R09 @1;200 for 1.5hrs with inversion every 30 mins and the negs look great!
How do the prints look?
I like pan f in rodinal 1:200 for 2 hours,
thin negs, but really nice to print
So typically TX developed in R09 is 7 minutes at 1:25, at 1:50 what's the development time?
W-a-a-a-y back when I processed B&W... my reason for higher dilutions (usually 1:100) was for better shadow detail without blocking highlights. I underdeveloped then increased negative contrast with selenium toner. This effectively lengthened the straight portion of the H&D curve (gamma curve) and improved micro-contrast. Ilford Gallery #3 was my favorite paper... also selenium toned to deepen shadows without blocking them. Selenium also improved the olive drab tone of Gallery papers to a nice very slight plumb color... very pleasant... and it improves archival qualities.
You need a minimum of 10ml of concentrate per roll regardless of the dilution used.
With smaller tanks this may preclude use of the 1:100 dilution.
My tank requires 400ml for a roll of 35mm so I've used only 4ml of developer when doing stand development. I haven't had a lot of practice, but 4 ml has worked. Is there some sort of calculation that concludes I need 10ml or is it just a manufacturers recommendation?
It's just manufacturer's recommendation, like lots of other things.
There are innumerable individuals who feel they know more than the manufacturers on any particular subject.
The manufacturer established that 10ml of concentrate is required per 80 square inches of film developed to be certain that sufficient active ingredients are present, i.e. to avoid exhaustion. This is based on the worst case. There is a chance that, depending on scene content, less than 10 ml will still provide adequate active ingredients, but one cannot be certain.
It comes down to "confidence or crap shoot."