GVK1 2 part pushing/speed increasing film developer

earlz submitted a new resource:

GVK1 2 part pushing/speed increasing film developer - Gives moderate grain, full or boosted speed, normal contrast, and high sharpness

Reference blog post with example images and more info: https://grainy.vision/blog/gvk1

Summary of characteristics

• Potentially speed increasing, seemingly by about 1 to 1/2 stop, depending on the film
• Ideal for pushing without contrast running away, while appropriately boosting shadows
• Very sharp with minor macro contrast edge effects (tree surrounded by sky will be darker than tree surrounded by forest) raising perceived sharpness
• Moderate...

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Read more about this resource...

Did you have an idea to reformulate the composition as a single solution? You can use potassium sulfite and some water to dissolve potash, and dissolve metol and glycine in TEA.

bnxvs said:

Did you have an idea to reformulate the composition as a single solution? You can use potassium sulfite and some water to dissolve potash, and dissolve metol and glycine in TEA.

Click to expand...

The concerns for single solution formulation are mostly regarding shelf life. Specifically, I don't have a problem keeping 2 bottles for the solution, but I do have a problem if the developer's characteristics change after just a few weeks. Another potential problem is that the stock solution would contain a lot of TEA. TEA causes sulfite to be a lot less soluble in water. This would likely not be a problem if I aimed for adding 200ml of stock per 1L but if aiming to use 100ml of stock, then I'd likely run into solubility problems. I've had similar formulas where the sulfite fell out of solution and wouldn't go back in after adding the TEA. The amount of developing agents and sulfite is fairly minimal though is the big concern, so I doubt that this would last very long on the shelf if a single solution.

This is true for sodium sulfite. But I have experimented with potassium sulfite and can say that mixing a 65% potassium sulfite solution with an equal volume of TEA is pretty stable. And it makes possible to make very concentrated solutions.
I tried mixing your formula as a single solution yesterday. In principle, the solution turned out. Unfortunately, I have a rather old glycine in stock (already quite dark in color) and therefore the solution turned out to be very dark, almost black. The test piece of film darkened in 18 seconds (at a 1:30 dilution).

The composition is as follows:
Stir with heating:
Metol 5g
Glycine 5g
in TEA up to 200ml.

Mix separately:
35.12 g of potassium metabisulfite
17.72g potassium hydroxide
Water up to 70-80ml
Add 20g potassium carbonate (potash)
Water up to 100ml

Gently, with constant stirring, pour an aqueous solution of sulfite into the TEA solution until a uniform solution is obtained.

bnxvs said:

This is true for sodium sulfite. But I have experimented with potassium sulfite and can say that mixing a 65% potassium sulfite solution with an equal volume of TEA is pretty stable. And it makes possible to make very concentrated solutions.
I tried mixing your formula as a single solution yesterday. In principle, the solution turned out. Unfortunately, I have a rather old glycine in stock (already quite dark in color) and therefore the solution turned out to be very dark, almost black. The test piece of film darkened in 18 seconds (at a 1:30 dilution).

The composition is as follows:
Stir with heating:
Metol 5g
Glycine 5g
in TEA up to 200ml.

Mix separately:
35.12 g of potassium metabisulfite
17.72g potassium hydroxide
Water up to 70-80ml
Add 20g potassium carbonate (potash)
Water up to 100ml

Gently, with constant stirring, pour an aqueous solution of sulfite into the TEA solution until a uniform solution is obtained.

Click to expand...

without a massive increase in the amount of sulfite though, is it possible to make this a long lived solution when kept at such a relatively high alkalinity with relatively low preservative?

Also of course, that's not to mention the big hike in price that comes with using potassium sulfite.

earlz said:

Also of course, that's not to mention the big hike in price that comes with using potassium sulfite.

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Sulfite is made directly in solution, from potassium's metabisulfite and hydroxide. It's not expensive at all, at least not more expensive than sodium sulfite.
50 grams of sulfite per 300 ml of concentrate is a sufficient amount of preservative to ensure a long shelf life. For example, the new HC-110 formula contains about the same amount of sulfite (15-20%).

bnxvs said:

Sulfite is made directly in solution, from potassium's metabisulfite and hydroxide. It's not expensive at all, at least not more expensive than sodium sulfite.
50 grams of sulfite per 300 ml of concentrate is a sufficient amount of preservative to ensure a long shelf life. For example, the new HC-110 formula contains about the same amount of sulfite (15-20%).

Click to expand...

50g per 300ml would require that only 100ml of water is used as well as different final dilutions (30ml to 1L of water) to make the working solution as well as eliminating glycol from the solution. The other concern is the 20g of potassium carbonate being dissolved in this. I'm unsure if TEA makes this less soluble but it is a concern. The viscosity of the final solution would be annoying but not worse than HC-110 I think. I do know that carbonate will actually increase the thickness of TEA though. I might making a small batch of this in the future if I can source the potassium salts for synthesizing potassium sulfite, or just buy a bottle of 65% potassium sulfite solution. In theory glycol could still be added to thin out the solution as well since it seems to not affect solubility of anything and still will likely make the glycin more easily soluble. From the reference I've seen, this might still go up against the metol solubility limit, though I've heard metol is easily soluble in glycol as well after reaction with TEA to remove the acidic salt from it. Either way, definitely requires quite a bit of thought on how to mix this rather than simply stirring in ingredients.