Simplifying SLIMT (a little anyway...)

[M Carter]

Summer's coming to Texas with those blown-out clouds, and I've been finding many images where I'm really upping the exposure, rating Acros at 50 or less, shadows on zone IV and so on. So holding delicate highs in the neg can be a challenge. Read up on SLIMT for contractions of more than a stop or so, but... all those bottles and formulas and dilutions seemed kind of "too much". So I broke out the calculator and came up with more of a 1-shot, day-in-the-darkroom formula (feel free to check my math):

75ML water
.25g Pot. Bromide
.75g pot. ferri

This gives you a small bach of ready-to-dilute bleach that can get you through many rolls or sheets; you can double or halve the recipe as needed. For instance, with an afternoon of testing to dial it in, I found 5ML of the above bleach solution to 500ML water for 5 minutes would cut very-well-exposed Acros (ISO 40 or 50) by about 2 stops; but it also sort of muddied up the mids. So I played with beefing up developing after the bleaching step, instead of doing a minus-1 contraction (my basic idea was cut a stop with bleach and a another stop with development), I did more of a plus-one. I ended up with good printable highs in the clouds - highs that would have been really well out of range; but a nice snappy look overall. I played around with 4-5 120 rolls and still had about 40ML of bleach left.

Anyway, this made the whole idea of SLIMT more appealing and easy for me to deal with, and seems to be working like a textbook case.

 

[Andrew O'Neill]

I used to use David's SLIMT, as well as bleach and monobath redevelopment technique a lot 20 years ago. But, since I started printing with unsharp masks and developing my film Pyrocat-HD, I found it unnecessary.
Glad you found a way to work for you. Thank you for sharing!

 

[M Carter]

I used to use David's SLIMT, as well as bleach and monobath redevelopment technique a lot 20 years ago. But, since I started printing with unsharp masks and developing my film Pyrocat-HD, I found it unnecessary.
Glad you found a way to work for you. Thank you for sharing!

Thanks Andrew - to me the main use of SLIMT is bringing extreme highlights into a printable range; and beyond that, it's kind if fascinating, the idea of bleaching back the latent image. I'm more of an "interpretive" printer than an "editorial reality" fan, but getting a neg that's ready for whatever I want to throw at it in printing is really interesting to me; the idea of having more neg control before serious printing is something I'd like to explore more... it's really a strange process. Most of my prints these days use several masks but that's a printing-stage thing. I'm going to try to play with this all some more.

 

[Raghu Kuvempunagar]

I found 5ML of the above bleach solution to 500ML water for 5 minutes would cut very-well-exposed Acros (ISO 40 or 50) by about 2 stops; but it also sort of muddied up the mids. So I played with beefing up developing after the bleaching step,

If I understand correctly, you used 0.01% bleach solution and increased the development time to get good mid tone contrast while keeping the highlights sane. How does this compare, in terms of actual results and ease of control, with developing the film normally and 1) using a proportionate reducer to reduce highlight density or 2) reholgenating bleach the negatives fully and redevelop the bleached negatives to a lower highlight density?

 

[Andrew O'Neill]

... And some films perform better with this technique than others. Out of all the films I tested, TMY was amazing.

 

[M Carter]

If I understand correctly, you used 0.01% bleach solution and increased the development time to get good mid tone contrast while keeping the highlights sane. How does this compare, in terms of actual results and ease of control, with developing the film normally and 1) using a proportionate reducer to reduce highlight density or 2) reholgenating bleach the negatives fully and redevelop the bleached negatives to a lower highlight density?

I've never found a bleach that just reduces highlight density on a neg (though I'm no expert) - the problem for me with bleaching has been shadow detail goes south before any appreciable highlight density loss. And of course there's an issue when highs are really seriously over developed, seems very hard for bleaching tricks to bring in detail vs. just lightening up an overall black blob on the neg? But not something I've experimented with.

The other issue for me is I often have one favorite frame or sheet, where clouds and light and exposure really worked the best, and so I'm always wary of messing with the neg and making it worse vs. better. Of course, pre-bleaching means you're messing with the neg (or the whole roll for 120, though I often cut rolls up if I plan for it when shooting). But overall the latent bleaching is appealing to me since so often my shooting conditions can be very harsh lighting.

I just returned from Scotland and Switzerland and have a lot of film to process, but I think that will be my last outdoor work for some time as I have some studio nudes ideas to pursue. So my next round of tests will likely be something like overexposing and boosting highs and seeing how latent bleaching can play with skin tones. Like, is there a way to push skin into a real ethereal/glowing look with this process? Maybe even shooting with a light red filter, like an 005 magenta wratten to get skin more pale and open and then push that look even further, something like the way skin responds to IR film outdoors? It's such an interesting concept and seems very repeatable and controllable. I'll just need to talk the mrs. into undressing for a lot of tests!!

 

[Doremus Scudder]

M Carter,

Just so you know, the amount of potassium bromide you are using in your SLIMT bleach is 3x what David Kachel recommends. If you look carefully, his stock solutions are 10% ferricyanide and 3.3% bromide, which are then used in equal amounts. You might try altering your proportions and see if it helps with mid-tone muddiness. It might make no difference at all; the extra bromide may just be unnecessary.

I've been using SLIMTs for many years now. I make 500ml of stock solutions like David Kachel advised: 10% ferri, 3.3% bromide, but I don't dilute this down further to make an intermediate stock solution like he does. I simply mix my SLIMT bleach directly from the concentrates using a very small graduated syringe to measure. Example: 0.5ml of each solution in 500ml water makes a 0.01% solution. I use anywhere from 0.04% to 0.005% solutions. Seems pretty simple to me once I have the stock solutions made up, which I do every couple of years...

The nice thing about having the stock solutions on hand is that I can easily mix a rehalogenating bleach from print bleaching. For this purpose I use 1 part ferricyanide solution to 3 parts bromide solution in varying amounts of water to achieve the bleaching strength I need. If I just need a little, I'll just use "eyedropperfuls" as a measure; exact proportions aren't that critical.

Best,

Doremus

 

[M Carter]

M Carter,

Just so you know, the amount of potassium bromide you are using in your SLIMT bleach is 3x what David Kachel recommends. If you look carefully, his stock solutions are 10% ferricyanide and 3.3% bromide, which are then used in equal amounts. You might try altering your proportions and see if it helps with mid-tone muddiness. It might make no difference at all; the extra bromide may just be unnecessary.

I've been using SLIMTs for many years now. I make 500ml of stock solutions like David Kachel advised: 10% ferri, 3.3% bromide, but I don't dilute this down further to make an intermediate stock solution like he does. I simply mix my SLIMT bleach directly from the concentrates using a very small graduated syringe to measure. Example: 0.5ml of each solution in 500ml water makes a 0.01% solution. I use anywhere from 0.04% to 0.005% solutions. Seems pretty simple to me once I have the stock solutions made up, which I do every couple of years...

The nice thing about having the stock solutions on hand is that I can easily mix a rehalogenating bleach from print bleaching. For this purpose I use 1 part ferricyanide solution to 3 parts bromide solution in varying amounts of water to achieve the bleaching strength I need. If I just need a little, I'll just use "eyedropperfuls" as a measure; exact proportions aren't that critical.

Best,

Doremus

Doremus, thanks, I just noticed this reply! I was wondering if I'd made any math errors - next time I test this I'll do the reduced bromide - thanks again!