Using potassium bromide to increase acutance and mid-tonality

[Hell-on-a-stick]

Will using potassium bromide in higher amounts, and restraining a given developer, like Tmax, or Acufine give greater acutance and midtonality once time is adjusted?

I am reading several forum posts about the addition of different chemicals to different developers in order to create 'better' results. many times my P3200 has come out of the fixer with blocked up highlights due to the action of fairly high energy developers. If I am going to add Kbr to the soup in order to avoid this...where should I begin in terms of weight? .5g? .25g? Any advice from the pros of APUG is appreciated.

 

[Bob Carnie]

I think you may be chasing a magic bullet here, adding different ingredients will have a effect , but regular dev's have been thoroughly thought out by the Manufactures and do a great job.
I have been using D76, Microphen, Pyro as instructed for years and have been very happy with the results.
The same can be said for Dektol paper developer, used for years and made IMO a few good prints.

 

[Ian Grant]

As Bob says no.

However with replenished developers the build up of Bromide and Iodide does increase acutance, but it's an equilibrium balance.

Agfa's D76 variant actually uses Bromide, but it's a bit like a developer starter, it's the Iodide films release that gives the acutance in replenished developers.

Ian

 

[Gerald C Koch]

Manufacturers make every effort to come up with well balanced developers. Tinkering with them will usually produce less than optimal results.

 

[nolindan]

Tinkering can be useful if one wants to add impact to some aspect of an image. Tinkering won't produce an overall improvement - developers have been tinkered with for 100+ years and there isn't much more that can be done. The last time a general improvement was seen was Xtol.

"Blocked highlights" are often just the opposite. TMax films have a huge linear density range - if you make a work print at 2 stops over exposure you should see the highlight detail the film has captured but that the paper is unable to accommodate. The solution is to carefully burn the highlights. Older films have a pronounced shoulder and compress the highlights - as a result they don't suddenly go white, as TMax's are prone to do, but gradually taper off. The downside is that highlight contrast/detail is lacking in the negative and no burning or dodging is going to get it back -- resulting in highlights that are truly blocked.

 

[Hell-on-a-stick]

I think you may be chasing a magic bullet here, adding different ingredients will have a effect , but regular dev's have been thoroughly thought out by the Manufactures and do a great job.
I have been using D76, Microphen, Pyro as instructed for years and have been very happy with the results.
The same can be said for Dektol paper developer, used for years and made IMO a few good prints.

Its possible, bob. I want something that will possibly make acufine, specifically, a bit less sensitive to agitation. I looked at the possibility of using a 'restrainer' when i started using to research caffenol. So, i've got the chem, i just wonder...

 

[Hell-on-a-stick]

Thanks for the tech info, Ian. I'll definitely check into these.

 

[Photo Engineer]

Iodide, when present in a developer, can actually repress acutance effects with high iodide films. It can have many effects depending on the film.

Iodide in a developer with a bromide film increases acutance.

Iodide in a developer with an Iodide containing film can actually have no effect or reduce acutance depending on Iodide level.

There is no easy answer, but the best answer is that neither bromide nor iodide should be relied on to improve acutance. Most modern films have the optimum level built into the emulsion. No "urging" from the process is needed. Just pick an HA developer.

PE

 

[c6h6o3]

The highest accutance negatives I've been able to obtain were all developed in ABC pyro.

 

[Hell-on-a-stick]

Thanks, PE. I'll examine my tech sheets more carefully.

 

[Hell-on-a-stick]

I'll definitely ad that to my list, jim.