Support our Sponsors, they keep FADU free: AG Photographic The Imaging Warehouse Process Supplies RH Designs Second-hand Darkroom Supplies |
> D-76 h |
*** Click here for the FADU 2015/2014 Yearbooks *** |
|
Thread Tools | Search this Thread | Display Modes |
#1
|
|||
|
|||
D-76 h
Metol...........................2,5g
Sodium sulfite (anh.).....100g Borax (decah.)..............2g Water..........................1l (by Grant Haist; published by Anchell&Troop) Should not increase activity with storage compared to D-76 (incidentally has rather short shelf life). However, sources differ in developing times - recomended starting points are same as for D-76, but there are reports of considerably reduced densities. Since the PH is exactly the same, with reduced amount of developer and no superadditivity, I'd indeed expect longer times. The question is, how much - looking at some developing curves, 30-40% increase seems reasonable. Do you have some experinences with this developer? |
#2
|
|||
|
|||
That's not the formula for D76h, that's a hypothetical formula that Haist came up with in a discussion with Troop. It's loosely based on the Eastman Kodak Research original Fine Grain developer published before D76..
The official Kodak D76h formula contains Hydroquinone Metol...........................2,5g Sodium sulphite (anh.).....100g Hydroquinone................5g Borax ..........................2g Boric Acid.....................15g Water..........................1litre Kodak publish quite a few variations of D76 in the 1930's Grant Haist would have been aware of the original EK Research fine grain developer, Troop wasn't Ian |
#3
|
|||
|
|||
Thanks for the correction Ian. Official one seems similar to D-76D (0,5g less metol, 8g of borax and 8g of boric acid).
|
#4
|
|||
|
|||
Here's a list of some of the D76 variants and similar developers like the Ilford PQ version Autophen.
Ian |
#5
|
|||
|
|||
A couple of questions on this, if I may...
- Does the increased activity of D-76 over longer storage time only happen to, say, half-full bottles; i.e. where there is some air in the bottle? Or does it affect full bottles also? - Can one expect any image quality differences between D-76 and D-76H? Thanks!
__________________
Regards, Svend Last edited by Svend; 15th May 2019 at 05:26 PM. |
#6
|
|||
|
|||
Hi Svend, reports say increased pH as result of hydroquinone oxidation...so, full bottle shouldn't change pH, I'd guess (only if was more interested in chemistry at school , can HQ react with oxygen form water?).
Some people swear that metol only developers give better edge sharpness than metol+HQ - as for my experiences, D-23 1+1 is very sharp, but I doubt that there is some difference compared to D-76 (at least up to 30x40 print from 35mm). Also, without superadditivity, metol only developer should build high density areas slower, providing less contrast (I have noticed and use this with D-23). Last edited by JakubV; 24th May 2019 at 08:55 AM. |
#7
|
|||
|
|||
Quote:
BTW, I've started storing D76 stock solution in 500ml bottles, so the whole bottle is used up in a single session. So no more storage in half-full bottles. I agree re. metol-only formulas. I use Perceptol a lot, esp. for scenes where there is a lot of contrast (snow, full summer sun, etc.) and find it to be terrific stuff. Very sharp, less contrast, a little softer rendering than D76, but still great depth of tones. Never tried D23, but I hear it is also excellent. Probably quite similar to Perceptol, I would guess.
__________________
Regards, Svend |
#8
|
|||
|
|||
Quote:
|
#9
|
|||
|
|||
Quote:
Ian |
#10
|
||||
|
||||
Please keep in mind: The first Formula is a metol only developer without redox system (usual HQ). Ths developer has a very short shelf life, less than a week. You are always in danger getting thin negatives. Beside this, metol only devs los around one stop.
From my point of view, this are specialized developers which should only used for fine grained film lik PanF+. There are said producing a slightly finer grain. Because the lose a stop it is normally easier using a slower film. But if you still use the film with the lowest ISO it's usage may make sense. |
Support our Sponsors, they keep FADU free: AG Photographic The Imaging Warehouse Process Supplies RH Designs Second-hand Darkroom Supplies |
Thread Tools | Search this Thread |
Display Modes | |
|
|