Kodak D-88, how does this (fogging?) developer work?

[BurntOutElectronics]

Normally I've used this developer here for b&W reversal of paper:

However, I've just tested a formula for Kodak D-88, it works, but now I want to understand how it works without any metol or phenidone.
How does the boric acid come into the mix?

Thanks

 

[BurntOutElectronics]

I'm also understanding now that hydroquinone is a developing agent also. No sure how I missed that part

 

[grain elevator]

I'm no expert but from what I've picked up along the way:
Doesn't look like a fogging developer going by the ingredients and the workflow in the screenshot (fogging dev would replace re-exposing step).
Hydroquinone works as a developing agent by itself at higher pH.

 

[BurntOutElectronics]

I'm no expert but from what I've picked up along the way:
Doesn't look like a fogging developer going by the ingredients and the workflow in the screenshot (fogging dev would replace re-exposing step).
Hydroquinone works as a developing agent by itself at higher pH.

You're right GE, not fogging.
Now you've got me curious, I wonder if there is any real advantage to just using hydroquinone and not adding phenidone

 

[Corn_Zhou]

You're right GE, not fogging.
Now you've got me curious, I wonder if there is any real advantage to just using hydroquinone and not adding phenidone

Using hydroquinone alone creates higer contrast than the P-Q combination. This effect was also used in Kodak's D-8 super high contrast developer for direct positive film.

 

[BurntOutElectronics]

Using hydroquinone alone creates higer contrast than the P-Q combination. This effect was also used in Kodak's D-8 super high contrast developer for direct positive film.

That's fascinating to note. Any idea why that is?

 

[koraks]

How does the boric acid come into the mix?

It creates a borate buffer together with the hydroxide. Although given the ratio between the two, the pH must shift all the way to the upper end. Not sure if this is the only or main reason why it's in there, but I'd expect so.

PS: it helps if you quote text from their original source because it preserves context. E.g. the D-88 formula you got from here: https://www.photrio.com/forum/threads/kodak-direct-positive-developer.31512/ In this case, it gives essential information about the "fogging?" bit because it's mentioned as a developer for direct positive paper, and post #5 in the thread contains essential information on that aspect.

As to why hydroquinone on its own gives 'high contrast' (the question is what is exactly meant by that - high dmax or cutting off of shadow detail?) - I suspect you may have to refer to the literature and that the underlying chemistry might be complex. You could start in e.g. Mees; https://archive.org/details/TheTheoryOfThePhotographicProcess Chapter XI might give some clues.

 

[Ian Grant]

What was your source for D-88. It's obviously quite a high contrast developer.

Ian

 

[Corn_Zhou]

The D-88 formula do look like half strengh D-8 though, albeit less bromide and added boric acid
Kodak D-8
Very high contrast film developer
Cold water 750 ml
Sodium Sulfite (anhydrous) 90 g
Hydroquinone 45 g
Sodium Hydroxide 37.5 g
Potassium Bromide 30 g
Cold water to make 1000 ml

 

[Ian Grant]

It's closer to D-85 which is a Lith developer, the major difference is the use of Sodium Hydroxide instead of Paraformaldehyde, so veery high contrast without infectious Lith style development..

It appears that D-88 was for an applied use with Document, Recording, Photomechanical, films & paper, terms used by Ilford.

Ian

 

[BurntOutElectronics]

It creates a borate buffer together with the hydroxide. Although given the ratio between the two, the pH must shift all the way to the upper end. Not sure if this is the only or main reason why it's in there, but I'd expect so.

PS: it helps if you quote text from their original source because it preserves context. E.g. the D-88 formula you got from here: https://www.photrio.com/forum/threads/kodak-direct-positive-developer.31512/ In this case, it gives essential information about the "fogging?" bit because it's mentioned as a developer for direct positive paper, and post #5 in the thread contains essential information on that aspect.

As to why hydroquinone on its own gives 'high contrast' (the question is what is exactly meant by that - high dmax or cutting off of shadow detail?) - I suspect you may have to refer to the literature and that the underlying chemistry might be complex. You could start in e.g. Mees; https://archive.org/details/TheTheoryOfThePhotographicProcess Chapter XI might give some clues.

A borate buffer is interesting. I'd imagine the precision on the amount of boric acid would be fairly critical because of it and the pot bromide are the only inhibitors I see.

I'll be sure to provide more links in the future.
And thanks for that literature, I'll be sure to have a read of it. I've got plenty to learn!

What was your source for D-88. It's obviously quite a high contrast developer.

Ian

The exact formula I used was a pinch different to that described on this website, but virtually the same.

I can definitely say after comparing strip tests that D-88 is certainly higher contrast than the other Dev I've used.

At least now my curiosity about this strange obscure developer is solved, at least at a fundamental level.

I'm sure you'd be wondering what the application is that I've been testing this developer in, it's actually a vintage photobooth.

 

[BurntOutElectronics]

It's closer to D-85 which is a Lith developer, the major difference is the use of Sodium Hydroxide instead of Paraformaldehyde, so veery high contrast without infectious Lith style development..

It appears that D-88 was for an applied use with Document, Recording, Photomechanical, films & paper, terms used by Ilford.

Ian

It's close relation to a lith developer also makes me curious on its open shelf life. Only time will tell!
I probably won't use it again, but good to know it works well.