SLIMT and Why You Should Be Using It

[df cardwell]

"Why am I interested in "00" performance of MG paper???"
To imitate paper response of platinum or Azo using multigrade paper
To improve the aesthetics of long tonal range negatives

Forgive me is this has already been covered,
but developer choice makes a significant difference in the response of paper
(although it has been poo-pooed by writers over the past 30 years,
anxious to defend variable contrast paper).

The conventional alternative to Dektol is Selectol-Soft (120) and so most of us are usually working with metol and metol/HQ developers.

LPD is a very different developer, which, with long scale negatives, can produce rich blacks and a longer range of light grays and whites. In my darkroom, it adds 2 zones to unfiltered MGIV over Dektol, between Zone V and Zone IX. A bit like a platinum response. A bit... depending on what the specific platinum process is doing for you.)

A glycin/carbonate developer (no metol, no HQ) makes an even longer transition from white to black, while producing strong paper blacks (unlike 120). Rodinal does the same thing, and Catechol, although glycin/carbonate is easier (I think) to work with. Sulfite/Glycin/Carbonate, pretty simple.

You can emulate a platinum palette on MG IV with TMY2 and a glycin/carbonate/sulfite paper developer.

I use TMY2 most of the time, for everything, and prefer to give normal development as much as possible. For me, it is easier to adjust the paper developer, and normal paper. Variable Filters and SLIMT are both in my toolbox for cases when long scale developers need some help.

Good luck.

 

[dancqu]

Let Us be Specific

So we need to look elsewhere for an explanation of what's
taking place.

If you take a print or negative and bleach it in a Potassium
Ferricyanide - Potassium Bromide bleach 1% of each then wash
and redevelop it (in room lighting) to completion it will be
restored to the same densities.

If you do the same but with little or no Bromide the redeveloped print
will be substantially lighter and won't reach the same densities and
the overall contrast drops.

The EXTREME dilution of a SLIMT bleach may be part of the explanation.
A 1% bleach is as much as 100 to 1000 times the strength of a SLIMT
bleach. With out bromide you do though note a drop in contrast.

So in the Sterry process the Dichromate, or SLIMT the Ferricyanide
is acting on the Silver halides in the emulsion and affecting the
development process, some halide must be being displaced.

More importantly, From David's cite of Mees&James: the HAlIDES
of SILVER PLAY NO PART in the contrastwise bleach. Minute
crystalline arrays of silver atoms are most affected. Dan

 

[dynachrome]

SLIMT

Why not just use fill flash and print normally? It's obvious when you look through the viewfinder that the contrast range is too high in a scene like this. If you forgot to use fill flash then have the negative scanned and adjust the contrast in pp.

 

[2F/2F]

Why not just use fill flash and print normally? It's obvious when you look through the viewfinder that the contrast range is too high in a scene like this. If you forgot to use fill flash then have the negative scanned and adjust the contrast in pp.

pp?

 

[Ian Grant]

The EXTREME dilution of a SLIMT bleach may be part of the explanation.
A 1% bleach is as much as 100 to 1000 times the strength of a SLIMT
bleach. With out bromide you do though note a drop in contrast.

In order of Magnitude the amount of Ferrycyanide is still quite significant, it's a very powerful oxidising agent.

Sure in the example given a 10% solution is diluted a further 10 %, then by 100 times but that still leaves 0.1g per litre. Compare that to a developer like Pyrocat or Rodinal where the amount of developing agent used will be only around 0.5g per litre, and then the amount of silver in a 10x8 sheet which is less than 4gm per sq meter, so a maximum of around 0.2g but more typically 2g per sq metre, so 0.1g per 10x8 sheet.

So now look again that 500ml SLIMT solution has a significant amount of Ferricyanide compared to the silver that's present. But the whole point of David's process is that the Ferricyanide is not in excess and can be varied to control the degree of contrast change.

More importantly, From David's cite of Mees&James: the HAlIDES of SILVER PLAY NO PART in the contrastwise bleach. Minute crystalline arrays of silver atoms are most affected. Dan

Something rather wrong there, as the latent image is held by the Silver halide crystals it goes without saying that the Silver halide plays a part in the process.

It's worth adding that there are plenty of other treatments such as Chemical Latensification that can be carried out with emulsions pre or post exposure, these are usually used to increase emulsion sensitivity, while the Sterry method & SLIMT are designed to decrease sensitivity.

Ian

 

[Ian Grant]

More importantly, From David's cite of Mees&James: the HAlIDES
of SILVER PLAY NO PART in the contrastwise bleach. Minute
crystalline arrays of silver atoms are most affected. Dan

Something rather wrong there, as the latent image is held by the Silver halide crystals it goes without saying that the Silver halide plays a part in the process.

Definitely something is very wrong it contradicts T.H.James own writings

G.I.P, Levenson of Kodak, Harrow Research facility, writes that James, Eastman Kodak, (Rochester Research) "claims" that certain compounds can be adsorbed to the silver halide on the outside of a silver halide crystal but not to silver and can have an inhibiting (or promoting) effect on the chemical development. J. Phys. Chem. 66 2416, 1962. Levenson & James also wrote papers together, TH James wrote numerous papers looking ito how chemicals interfaced with silver halide crystals.

If this is the case with Dichromate and Ferricyanide it would explain why the Sterry process works pre or post exposure and also why SLIMT works at a low level, only sufficient Ferricyanide is needed to be adsorbed (complexed) with the silver halide on the outer surface of the crystals to inhibit & retard development.

This same process of adsorption is how organic anti-foggants like benzotriazole work. (Sheppard 1927 E.K. Research)

Ian

 

[dancqu]

Fits My Thinking Quite Well

Something rather wrong there, as the latent image is held
by the Silver halide crystals it goes without saying that the
Silver halide plays a part in the process. Ian

Silver as a halide is very oxidized. As a halide the ferricyanide
will not alter silver's state of oxidation. Ferricyanide will
though alter elemental silver's state of oxidation.

Photons will reduce silver in combination with a halide to
elemental silver. As we say the silver prints out. It is those
most exposed reduced silver sites, as microscopic as they
may be, which are most affected by a ferricyanide. Dan

 

[Ian Grant]

The chemistry at the silver grain / gelatin interface isn't so straight forward. There are other bonds between Silver & Gelatin, and chemicals that are adsorbed can have an effect where they wouldn't with a straight silver bromide bond. Add into that mix the presence of Sulphur which is present in the Gelatin and key to the Silver/Latent image specks.

James isn't suggesting the halide is replaced, rather that the negative charge (due to excess halide) on the outside of the silver grain binds it to the gelatin, some of the gelatin/sulphur binding to the Silver ions which releases bromide, the gelatin interface is positively charged allowing adsorption across it which in turn can inhibit (or promote) development depending on what chemical is adsorbed.

Ian

 

[ic-racer]

Why not just use fill flash and print normally? It's obvious when you look through the viewfinder that the contrast range is too high in a scene like this. If you forgot to use fill flash then have the negative scanned and adjust the contrast in pp.

Interstingly , last week I was just doing a Friedlander-inspired landscape project with a superwide 65mm on 4x5 using a fill flash. (The Horseman FA has a flash shoe on top!)

 

[ic-racer]

Forgive me is this has already been covered,
but developer choice makes a significant difference in the response of paper
(although it has been poo-pooed by writers over the past 30 years,
anxious to defend variable contrast paper).

The conventional alternative to Dektol is Selectol-Soft (120) and so most of us are usually working with metol and metol/HQ developers.

LPD is a very different developer, which, with long scale negatives, can produce rich blacks and a longer range of light grays and whites. In my darkroom, it adds 2 zones to unfiltered MGIV over Dektol, between Zone V and Zone IX. A bit like a platinum response. A bit... depending on what the specific platinum process is doing for you.)

A glycin/carbonate developer (no metol, no HQ) makes an even longer transition from white to black, while producing strong paper blacks (unlike 120). Rodinal does the same thing, and Catechol, although glycin/carbonate is easier (I think) to work with. Sulfite/Glycin/Carbonate, pretty simple.

You can emulate a platinum palette on MG IV with TMY2 and a glycin/carbonate/sulfite paper developer.

Excellent, thanks for posting. I'll admit in 30+ years I have been a Dektol person.

Without sounding like a broken record, you wouldn't happen to have any paper curves to post?

 

[Ian Grant]

Excellent, thanks for posting. I'll admit in 30+ years I have been a Dektol person.

Without sounding like a broken record, you wouldn't happen to have any paper curves to post?

You need to learn how to use Selectol Soft (D165 / ID-3 or Adaptol) alongside Dektol, another alternative is Dr Beers Variable Contrast Developer which used to be printed in the older Ilford Galerie Datasheets.

Using developer controls you can vary a paper's contrast by nearly 3 grades with a Chloro-bromide paper, 1 up and 2 down. It works with graded papers and VC, slightly less with a Bromide paper.

I thought John Blakemore might have curves in his "Black & White Photography Workshop" book but he doesn't. He plays with the Zone system as if it's a musical instrument and is probably one of the finest printers around.

Ian

 

[df cardwell]

Without sounding like a broken record, you wouldn't happen to have any paper curves to post?

No, sorry, I don't post curves anymore. (Folks either want to be spoon fed, or argue about what they are looking at, and I'm not good at doing either.)

Why not get some LPD and use it as a first step ? Contact print a step wedge and develop it in Dektol, and LPD, and you'll see quickly what it does. I'd be happy to talk about what you want to do, send me a PM.

don

 

[ic-racer]

Without sounding like a broken record, you wouldn't happen to have any paper curves to post?

No, sorry, I don't post curves anymore.

Ok, thats fine.( I did enjoy the graphics in your Rodinal article though )
But I am going to presume you are saying that the curve is likely to be straighter in the middle than the "00" curve in the link I posted above.

 

[df cardwell]

ic-racer: I'm sending you a PM.

 

[Murray Kelly]

I have read the OP and the Kachel site referred to. I am confused as to the final concentration of Fericyanide. I use a lot of copy film and would like to take advantage of the contraction offered by this process.

Katchel refers to diluting a concentrate of 10% Fericyanide by another 10 to a stock solution. 1% or 10mg/ml. Then dilute 10 times to a working solution? 100ml/1L = 1mg/L

The OP says to take 10ml of that original 10% concentrate solution and dilute to 1L. Is there is a discrepancy of an order of magnitude?

I am not arguing for/against the process, merely the final concentration of fericyanide. Is it 10mg/L or 1mg/L which is added to the 1L of water to bathe the undeveloped film in?

Seniors' Moment.
Murray

 

[Murray Kelly]

Never mind. I see where the OP skips a step and dilutes only 10ml down to a litre. Same result. 1g/L or 1mg/ml.
Thanks.
Murray

 

[georg16nik]

Bump!

In another, recent thread, I dropped the bomb about bleaching the Adox CMS20 latent image.

So, lets resurrect this thread.
Might be helpful for some folks.

 

[pdeeh]

I'd be interested to know if anyone has experience of doing this with any of the lith films, such as Arista OrthoLitho.
Short of that, as I've got some, I might as well give it a try myself sometime.

 

[Old-N-Feeble]

I'd have to see far more comparative examples before trying a new process. Google finds nothing.

 

[doctorpepe]

I know this is an old thread and if I missed an answer to this question? I apologize but has anyone used this on litho film to reduce contrast and this use it as an inexpensive copy negative film?

 

[georg16nik]

I know this is an old thread and if I missed an answer to this question? I apologize but has anyone used this on litho film to reduce contrast and this use it as an inexpensive copy negative film?

Like I wrote back in 2014, SLIMT works great with Adox CMS20 and I've also used with Agfa Copex-Rapid.
Give it a shot!

 

[Patrick Robert James]

Like I wrote back in 2014, SLIMT works great with Adox CMS20 and I've also used with Agfa Copex-Rapid.
Give it a shot!

I'd love to see examples of that.

 

[georg16nik]

I'd love to see examples of that.

When I get around my darkroom and archives this month, I will scan a frame or a print that will fit a flatbed scanner.

 

[doctorpepe]

Like I wrote back in 2014, SLIMT works great with Adox CMS20 and I've also used with Agfa Copex-Rapid.
Give it a shot!

Ok. May get some arista litho and try it.

 

[L Gebhardt]

I know this is an old thread and if I missed an answer to this question? I apologize but has anyone used this on litho film to reduce contrast and this use it as an inexpensive copy negative film?

Just last night I tried making a positive from a very contrasty negative on Inkpress Media Regent Royal Hard Dot Camera Film. I gave 3 minutes in the potassium ferricyanide at normal dilution and 4 minutes in HC110 8ml syrup in 500ml water. Results are encouraging, but I still need to work through a few issues. One is the film came with straight scratches in the emulsion, so maybe I need a different package. Two, my development isn't even. I used trays and there are some areas that didn't get developed. These look like the same patterns I noticed in the bleach when the antihalation dye clumped in the eddy currents from the agitation (quite neat to actually get to watch under safe light). A longer dev time and more random agitation pattern should be able to fix this.

My exposure time was .5s flash and then 32s exposure. The light was from royal blue LEDs and on my darkroom automation meter the intensity was adjusted to 6.00.

Attached is a crappy iphone scan to show the tonality, scratches, and the uneven development. I think the blue is an iphone interaction with the lightbox. The neg looks pretty even colored, except the brown areas that I think are agitation induced areas of less development. The dust is most likely my fault since I was only focusing on getting the exposure and development figured out.