water vs acid stop bath for Rodinal tests results

[ramiro_aceves]

Hi B/W friends.

 

As I promised, I send you my results about using 1 minute water stop

bath instead 3 minutes acid stop bath for development of TURA P150 at

EI 70 in Rodinal 1:50 for 11 minutes. I can NOT see any diference in

grain pattern between them. I have compared same density frames to

avoid diference in grain caused by exposure diferences. So I will

use the water bath from now with,although grain is the same here, it

is cheaper and avoids pinholes.

 

I am planning a detailed grain test among Rodinal 1:25, 1:50 and

1:100

to see the real effect of dilution in acutance, resolution and grain.

I am trying to get the same contrast index in all dilutions to make

good comparisons. Also I need to shoot the same target and avoid any

camera shake to make a good test.

 

I will keep you informed. Any ideas will be welcome.

 

Ramiro.

[al_kaplan1]

I'm not sure why you're using such a long water bath or stop bath. I just fill my tank with water, do a couple fast twists and inversions, pour it out and pour in the fixer. It's worked for 40 years.

[nicholas_t.]

Ramiro, <p/>

I found your old vs new (dark vs clear) Rodinal experiment really interesting! I have that ancient bottle of Rodinal, I keep meaning to test - soon! <p/>

Regarding, the dilution ratios and grain - I am fairly sure this is a predicatable one. However, I've been wrong before. But, as I see it, it should come down to the nature of the developer, which is in a caustic solution. So, that you get a finer grain @ 1:100, slightly larger @ 1:50, and golf balls @ 1:25 is natural. The pH should be fairly high @ 1:25 (I am guessing 11) and lowish (maybe 9 or so) @ 1:100. <p/>

As I have recently found out, pH is a big factor in developer activity. Perhaps, even more so than actual developing agents in some cases. I suppose it is why they called it an 'activator' :-) <p/>

Apparently, the pH level also has quite an effect on grain as well.

[jimvanson]

Ramiro...I suggested the water stop in your other post. I've used it for many rolls. I fill the tank with water and agitate 4 or 5 times empty the tank and repeat the procedure. I believe that stop or even water is totally unnecessary. I think the reason we use it is so that our fix lasts longer still I've gotten into the habit of filling with water twice. Now for the Rodinal...I bet you a nickle that you will get larger grain, better acutance, more shadow detail and thus better tonality with the more dilute Rodinal (I believe you get slightly better film speed too BUT I can not prove that)...all things being equal. Rodinal at 1+100, properly measured, in a tank that you agitate 10 times in the first 30 seconds and then one inversion every 30 seconds will provide a compensating effect. (depending how you agitate you may have to increase this to two inversions every 30 seconds. BUT please remember over agitation destroys any compensating effect). I�ve used Rodinal at up to 1+400 for stand developing (APX @ 200 in 3mls of Rodinal plus 1200mls water agitate 5 times in the first 30 seconds, two complete gentle inversions after 20 minutes, two complete gentle inversions after 40 more minutes, then let sit for one hour more).. The negs were very sharp although I don�t think I could tell the difference between 1+100 and 1+400. The 1+400 had better shadow detail and the grain seemed larger. Email me if I can be any help...jim

[robert_d.1]

I would be interested to find this past rodinal topic if anyone knows?

I'm also curious what the negatives looks like from an extended time such as 1hr 40min? Shadows must looked beefy.

[jimvanson]

Ramiro...I wanted to add a couple of more thoughts re dilute Rodinal. Some people feel that 3 mls per roll is not enough Rodinal. They feel that the rodinal becomes exausted before development is completed. There is another group who feel that the water you use is very important when using dilute Rodinal...that since your using so little Rodinal the waters PH can skew results. Both of these groups would still develop at 1+100 but they would use 6mls of developer to 600 mls of water per roll...jim