Dilution & Agitation

.

A
.

  • 5
  • 1
  • 212
Promethea Moth

D
Promethea Moth

  • 2
  • 1
  • 175
On The Nest

D
On The Nest

  • 3
  • 1
  • 182
Reception area - Spain

A
Reception area - Spain

  • 3
  • 3
  • 304

Recent Classifieds

Forum statistics

Threads
189,622
Messages
2,644,433
Members
97,311
Latest member
aaronzomback
Recent bookmarks
0

thefizz

Member
Joined
Dec 8, 2004
Messages
2,318
Location
Ireland
Format
Medium Format
Dilution: I mostly use Rodinal 1:25. If I try 1:50, what differences can I expect from my negs.

Agitation: What will increased agitation do for my negs?


Thanks,
Peter
 

titrisol

Subscriber
Joined
Aug 2, 2004
Messages
1,964
Location
RDU / UIO
Format
Multi Format
If you dilute Rodinal 1+50 or 1+100, times should be increased. our negatives will look smoother, drop contrast a bit and grain will be smaller (IMHO)

The mlre you agitate the more contrast you create on the negative, the shorter the time you should develop.
If you plan on diluting rodinal, you want to cut you agitation to once every other minute or so.
 

modafoto

Subscriber
Joined
Oct 17, 2003
Messages
2,101
Location
Århus, Denma
Format
Medium Format
titrisol said:
If you dilute Rodinal 1+50 or 1+100, times should be increased. our negatives will look smoother, drop contrast a bit and grain will be smaller (IMHO)

The mlre you agitate the more contrast you create on the negative, the shorter the time you should develop.
If you plan on diluting rodinal, you want to cut you agitation to once every other minute or so.

I simply second that!
 

Claire Senft

Member
Joined
Dec 7, 2004
Messages
3,239
Location
Milwaukee, W
Format
35mm
Go easy with the agitation

The purpose of agitation is to bring new devloper into contact with the emulsion. Whatever amount of agitation is used should be gentle to prevent developer from surging thru the sproccket holes when using a film with sproket holes.
 

titrisol

Subscriber
Joined
Aug 2, 2004
Messages
1,964
Location
RDU / UIO
Format
Multi Format
PS. I have settled for Rodinal 1+50 as standard dilution and 1+100 for EFKE 25.

modafoto said:
I simply second that!
 
Joined
Jan 24, 2005
Messages
279
Format
Multi Format
The way I understand it, though I could be corrected is in periods where no agitation is happening the developer in contact with very dense regions of the negative becomes exhausted much before the thin areas. Thus, if you leave a tank sitting the developer will work on the hilights and stop (for lack of a better word) developing the shadows very much, resulting in a lower contrast between shadow and hilight the less you agitate and more stark contrast the more you agitate because you are putting 'fresh' developer on those shadow areas.

(experts, is this correct?)
 

Donald Qualls

Subscriber
Joined
Jan 19, 2005
Messages
11,305
Location
North Carolina
Format
Multi Format
The other thing you do, by increasing contrast via agitation and compensating with shorter development, is lose shadow detail. The shadows get about the same amount of development from the same time in the soup, regardless of agitation, because the developer doesn't exhaust in shadow areas (thus bringing in fresh developer has little effect in those area). So, developing longer with less agitation to get the same overall contrast will increase shadow development (which increases the real film speed). Likewise, higher dilution (which also requires longer development to obtain the same contrast) will do the same, again because even the dilute developer doesn't exhaust in the shadows.

I've wondered if the main reason people find they need to expose at 2/3 to 1 stop under the film's rated speed isn't because they agitate too much or use too fast a process. I use a highly dilute developer, reduced agitation (10-15 seconds every 3 minutes), and develop for 3-4 times the manufacturer's times for "normal" strength developer -- and with the manufacturer's rated speed, I never have problems with lack of shadow detail unless I simply didn't give enough exposure.

Oh, and I get these effects with TMY -- in theory, they should be stronger with "traditional" grain films like Plus-X or Tri-X; that does seem the case with J&C Pro 100, with which I've gotten excellent shadow detail.
 

Will S

Member
Joined
Nov 30, 2004
Messages
716
Location
Madison, Wis
Format
8x10 Format
Donald Qualls said:
I've wondered if the main reason people find they need to expose at 2/3 to 1 stop under the film's rated speed isn't because they agitate too much or use too fast a process. I use a highly dilute developer, reduced agitation (10-15 seconds every 3 minutes), and develop for 3-4 times the manufacturer's times for "normal" strength developer -- and with the manufacturer's rated speed, I never have problems with lack of shadow detail unless I simply didn't give enough exposure.

Oh, and I get these effects with TMY -- in theory, they should be stronger with "traditional" grain films like Plus-X or Tri-X; that does seem the case with J&C Pro 100, with which I've gotten excellent shadow detail.

Maybe. I think most developer times are too long, resulting in blocked highlights. Barry Thornton has an interesting article at:

http://web.archive.org/web/20040202094533/www.barry-thornton.co.uk/devtime.htm

where he outlines how to test dev time.

Thanks,

Will
 
Photrio.com contains affiliate links to products. We may receive a commission for purchases made through these links.
To read our full affiliate disclosure statement please click Here.

PHOTRIO PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Ilford ADOX Freestyle Photographic Stearman Press Weldon Color Lab Blue Moon Camera & Machine
Top Bottom