contrast of negatives

[bluenote]

Hello all,

I am experiencing lack of contrast at my negatives for some time.
In this article http://www.thewebdarkroom.com/?paged=2 "Flexible film" Mr. Sanderson is writing the agitation and its parallel to the film contrast.

Till now, I have thought that constant agitation increases contrast, but the article says that the contrast actually drops !
This is what I am experiencing with my negatives for quite a long time ( now I know why ). Here is my question.
For sheet 5x7 film development I am using jobo drums which are filled with 4 negatives for one process.
This arrangement of film inside needs constant agitation - the drum is not filled up completely - I use 600ml of ID11 for JOBO 2840


How can I develop sheet film unless I fill up every drum ( more 1 liter ) with developer ?
Can you please give me any suggestions ?

Thank you,
Jiri

[Jim Noel]

600 ml of developer is not enough to fully develop 280 sq inches of film {4- 5x7's). You need twice as much, but 1000 ml will probably suffice in a Jobo. Your other alternative is to switch to a lower dilution or a more potent developer so that the quantity will contain more developing agent.

[Jim Graves]

Ilford's PDF sheet for ID-11 is here: Link (http://www.ilfordphoto.com/Webfiles/200621612182416.pdf)

It indicates 1 liter of stock ID-11 will develop 10 rolls of 120 or 135/36 film (p. 7)

One roll is equivalent to approximately two 5x7 negatives (Anchell & Troop's Film Developing Cookbook) ... meaning that one liter of stock ID-11 should be the minimum used for five 5x7 negatives ... which would mean a minimum 800ml of stock for 4.

So as Jim Noel suggests above ... your developer is exhausted before it gets a chance to fully develop your negatives.

[bluenote]

Thank you Jim, this is another aspect I haven't realized.

[bluenote]

Ilford's PDF sheet for ID-11 is here: Link (http://www.ilfordphoto.com/Webfiles/200621612182416.pdf)

It indicates 1 liter of stock ID-11 will develop 10 rolls of 120 or 135/36 film (p. 7)

One roll is equivalent to approximately two 5x7 negatives (Anchell & Troop's Film Developing Cookbook) ... meaning that one liter of stock ID-11 should be the minimum used for five 5x7 negatives ... which would mean a minimum 800ml of stock for 4.

So as Jim Noel suggests above ... your developer is exhausted before it gets a chance to fully develop your negatives.


Thanks to both Jims :-),
Ok, so once I solve the quantity of developer problem, is still the constant agitation the issue ?

[Vaughn]

My opinion -- Not an issue -- just develop a little longer to compensate for any drop in contrast due to constant agitation.

[bluenote]

My opinion -- Not an issue -- just develop a little longer to compensate for any drop in contrast due to constant agitation.

develop longer ? According to the article of Andrew Sanderson mentioned above....

"....When I did lots of different ratings and development times in the early years of my career, I also found that agitation could alter the look of a negative.
Normal agitation is usually taken to be three inversions of a tank every minute and increasing the number of inversions/agitations will increase contrast. BUT, taken to an extreme, with continuous agitation, contrast actually drops!
I think it is because the developer is not allowed to sit on the surface and work properly when constantly in motion,....."


Well now, it is confusing to me.

[uhner]

Longer development with continuous agitation gives higher contrast than short development times with constant agitation.

I believe the article says that constant agitation produce lower contrast negatives compared to normal agitation, all other things being equal.

[bluenote]

Longer development with continuous agitation gives higher contrast than short development times with constant agitation.

I believe the article says that constant agitation produce lower contrast negatives compared to normal agitation, all other things being equal.

Thank you, I will work on it .

Jiri

[Bruce Watson]

Like the others, I think your problem is developer exhaustion and has nothing to do with agitation. And it's easy enough to test -- increase your stock developer quantity to the recommended levels and try again without changing anything else about your process. If your contrast increases, you found the problem, and you can adjust from there.

I've read the article pointed to by your URL. There's not enough information there to let me draw any meaningful conclusions. But... what he says doesn't match my experience. In my experience, increasing agitation does in fact increase gamma (aka contrast index). IOW, more agitation = more contrast, all other things being equal. Assuming agitation that makes sense for photography.

I'm sure you could find an agitation scheme that would actually make development more difficult -- one that was so fast and violent that it makes carrying away developer by-products difficult, and supplying fresh developer to the emulsion difficult. But this wouldn't make sense for photography. Nothing you would normally do using a Jobo tank to develop film would be that fast or violent IMHO.

When in doubt, check multiple sources. If you can find independent sources all citing the same results there's a better chance that what they are talking about is real. If it's just one guy and no one else can reproduce his results, then look at his results with a healthy amount of skepticism.