Kodalk, Sodium Metaborate, Balanced Alkali?
So yes I am somewhat of a newb but if I may I have a question that I didn't really find an answer to searching the forums. I have been given an assignment through school to shoot B/W architectural exterior night shots with a 4x5. My instructor suggested that I use "Kodalk" to aid in development of my negs. He also used the term balanced alkali interchangeably but I haven't been able to find out much about it other than how to produce some.
The questions that I have are: Does it do what I think it does as far as producing a larger tonal range therefore working better for night? How would I use it inline with Sprint systems developer, stop, and fix which is what we use at school? In place of the developer or in conjunction with? And what kind of times would I be looking at for something like Kodak T-Max 400?
Thanks for any direction.
I hope Acros is still made in 4x5, I can't remember if it still is! I use it in 120 size, which is what I shot my example pic with. Mamiya 645 camera.
Sodium metaborate is an alkali, a moderate one, that kodak calls kodalk or kodak balanced alkali. Is chemically close to borax but a bit more alkaline. It´s use is to be part of the developer in the DK kodak developer´s series, it also appears in X-tol or Mytol, and it could be used in the water bath thing described. Today´s films aren´t as sensitive to water bath as they used to be and since you are a beginner try a low contrast developer or try to dilute your usual developer since this tends to increase compensation effects (and also adjacency effects). It might be possible that with gentle agitation you might get that effect you are searching for. Also try to expose a bit more and develop a little less. The use of larger formats tend to give smoother tonality.
if you are a beginner, keep it simple and repeatable, with some calculated changes you might get there better. And testing is a must.
Be carefull with somethings wrote about the subject, some are just things people like to believe, others plain mith, others come from experimenting materials that are not around anymore.
Metaborate is sometimes used as bath 2 in a split development system. Your instructor sounds as though he is not a very good educator, unless this is an exercise in independent discovery.
For an explanation of what metaborate is, but not how to use it, see:
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Much appreciated for the feedback. I think that I may just go the route of a low contrast/fine grain developer instead. As far as being a decent educator, he is good but darkroom is not his field. Our darkroom instructor wanted me to figure it out for myself but seemed to think that it was not the best way to go. I agree with the use of Acros as well, I have shot some in 120 but I will look into some sheets.
You said any direction was welcome, so here is mine :-)
Exposing at night is no different than exposing during the day except you have to expose longer. This often entails dealing with reciprocity and high-contrast subjects (light or illuminated objects in addition to dark shadows).
However, if you are shooting architecturals and don't have to deal with subject movement, you can calmly open the shutter and expose to your heart's content.
Your challenges, as I see them, are to render detail in the shadows while not burning out the illuminated parts of the scene. Often, you can do this with increased exposure and reduced development just fine (typical Zone System contraction).
Another useful and often rewarding approach is to double-expose. Make one exposure earlier in the evening or just after dusk for the exterior before the window lights and street lights come on. Then wait an hour or so and make a second exposure for the lights. Problems here are moving the camera between exposures, film popping, etc. but I've done it a time or two with good results.
The chemical solutions to the problem all aim at finding a development scheme that is compensating, i.e., develops more in the shadows than in the highlights compared to "normal" development. This is usually done by reducing agitation, diluting the developer or combinations of the two. I hesitate to recommend you do anything without testing.
However, I have often "shot first and tested later." This entails making several negatives, ensuring adequate exposure (read, I overexpose to be sure) and then developing using different schemes to get a usable neg. You might be able to do that. I would recommend using the developer you are used to and see what results you can get with it.
So, the down-and-dirty nitty-gritty: Get your hands on a reciprocity correction table for your film if you don't have one. Go out and make negatives. Read the shadows if you can and base exposure on that. Then add a stop for safety. At any rate, don't forget to add the correction for reciprocity failure if your times are more than 1 second. If you have an averaging meter and there are lots of bright light sources in the scene, overexpose a couple of stops, make several negs and then develop on at about 60% of you regular development time and see how it prints. Adjust the development time if needed for the next neg. I'll bet you get something usable. Keep records so you don't have to sweat it next time.
If you need to change developer/agitation scheme, start with a weaker dilution of the developer you use (say 50%) and cut your agitation (e.g., if you agitate every 30 seconds, try agitating once a minute after an initial period of more frequent agitation. A rough rule is: if you dilute by 50%, you double the time to get the same results. So, try the 50% dilution and 1.5 times the original time. Again, if you have 8 or 10 negs, you can adjust for the next try if your results are not what you need.
Hope this helps,
A couple of quick notes to help put your instructor's comments in context.
Kodalk is the same as Kodak Balanced Alkali, and was Kodak's proprietary incarnation of sodium metaborate. Who knows if Kodak added some tiny fraction of one or another material to enhance performance or ease of mixing, the basic fact is that they all can be used exactly the same way.
Sodium metaborate when dissolved in water is alkaline. Some sort of alkaline environment is needed to activate all developers used for ordinary film development. Various alkalis are stronger and some weaker. The weak ones tend toward creating a gentle developing action and are well suited to giving you a wide tonal range. Stronger alkalis are more suited to giving very vigorous development and making a snappy negative, even from a subject with a limited tonal range.
To put that in english:
Weak alkali tends to soft development - good for subjects with extreme brightness range (or accidental overexposure!)
Strong alkali tends to energetic development - good for very flat subjects that need a boost.
Middling alkalis tend to average development - good for average stuff.
Two bath development is one way of getting compensating development. The gist of it is that the film is first put until saturated and in many cases until a certain amount of developing takes place in a developer solution and then placed in an alkaline bath which activates developer already soaked into the film. The weak image in shadows is encouraged to develop very fully, while the highlight areas use up their developer by exhausting it. In essence, two bath development custom processes each area of the negative. Very similar to water bath development as described in a post above except that with two bath development, the film just goes into each bath one time rather than cycling back and forth.
Some two bath developers are specially compounded to not have any activity while the film is in the first bath and only start the development process in the second. Generally, with two bath developer systems, the time in the second bath is not considered to be critical, as long as it exceeds the time needed to exhaust the developer or have it diffuse out of the film. Too short a time would result in underdevelopment. Three minutes is very common.
Most two bath developers use ordinary developers that do have activity while the film is in the first bath, and when the film is placed in the second bath, the compensating action begins. Many ordinary developers like D-76 and D-23 have been used as the first bath in two bath systems. There are nearly as many formulas and schemes for two bath development as there are practitioners. A simple internet search will give you endless different formulas. If you try two bath developing, don't try to try every scheme out there. Keep it simple. I recommend you start with some simple scheme and a basic developer like D-76 followed by a metaborate or borax bath.
So, what alkali does what?
Borax, Sodium Metaborate, and Sodium Sulfite are considered mild alkalis at about a 9 pH.
Mild alkalis produce low contrast and need longer in development times.
Sodium Carbonate and Potassium Carbonate are moderate strength alkalis at about 10 -11 pH.
Potassium hydroxide and Sodium Hydroxide are caustic alkalis and are very strong and are used in powerful, quick acting developers.
To make it from common materials you can react stochiometric quantities of borax in an aqueous solution with sodium hydroxide to make sodium metaborate. The NaOH is nasty strong stuff. I use it in making soaps, and am used to handling it carefully.
So more dilute, or other suggestions given here, I agree are more appropriate approaches.
my real name, imagine that.
Originally Posted by Mightycasey
I am new to this forum but would like some help with a problem
Am in the process of making some PMK (Pyr-Metol-Kodalk) developer.
Am having trouble dissolving the sodium metaborate in the water. The quantities are:
2l distilled water
at about 25 degees Celcius
Any body out there who can help??