D-23 Required Amount of Chemistry?

sanking said:

I would suggest about 5+5 at 75F for Ilford FP4 if the negatives are to be printed with a cold light. If the negatives are too weak, increase temperature to 80F, if too strong, drop to 70F.

Sandy King

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Thank you, will give it a try.
Regards,
John.

" "Solution B is where the compensation comes in. In solution B the developing agent quickly exhausts itself in the high values where the greatest density lies, while the low values continue to develop. So, essentially, you develop in solution A until your high values are almost where you want them, then you place the film in solution B and develop until the shadow values are where you want them. If you are not experienced at development by inspection, you may have to do a little experimenting to get the times just right."
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Sandy:
Based on the above statement you provided, I may be wrong in shortening my time in Solution B, since the prescribed time (four minutes, rather than my three) would allow the shadows to develop more fully (but not the highlights due to the compensating effects, etc.) Thank you for reminding me of that principle.

Also, how do you handle film and equipment currently with the airlines and foreign travel? And do you develop your film over there, or bring it home undeveloped and hope? --Henry

Henry,

Yes, extending time in the B solutin will optimize film speed. Understanding the basic principles of the mechanism of two bath development is really useful.

In traveling by air I carry all of my film on board and don't worry about the screening. In many years of travel I have not seen any sign of damage from running film through the screener. And I always bring my film home for development. Proper development is absolutely key for me and whenever possible I want to do it myself, and in my working environment. The two or three days when I develop film after a long trip is a magical time.

Sandy King

htstanley said:

"Sandy:
Based on the above statement you provided, I may be wrong in shortening my time in Solution B, since the prescribed time (four minutes, rather than my three) would allow the shadows to develop more fully (but not the highlights due to the compensating effects, etc.) Thank you for reminding me of that principle.

Also, how do you handle film and equipment currently with the airlines and foreign travel? And do you develop your film over there, or bring it home undeveloped and hope? --Henry

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John Roberts said:

What if D23 were used for M/F in small tanks?
I wondered what kind of result could be expected
without Sol. B, or possibly some testing would need
to be carried out. Regards, John.

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I use an 8-80 formula D23 at 1:7 dilution; 120, 500ml.
A few inversions at developer in, 3 or 4 at 1 minute and
the same at 2 minutes intervals; Across 16 minutes.

My guess, the B bath is superfluous using the above
processing. The high dilution with it's consequent rapid
local depletion produces lots of compensation. Dan

dancqu said:

I use an 8-80 formula D23 at 1:7 dilution; 120, 500ml.
A few inversions at developer in, 3 or 4 at 1 minute and
the same at 2 minutes intervals; Across 16 minutes.

My guess, the B bath is superfluous using the above
processing. The high dilution with it's consequent rapid
local depletion produces lots of compensation. Dan

Click to expand...

Thanks for the information. 1:7 seems a quite weak dilution on your formulation and this may well be producing your required compensation.
I have no Kodalk at present but will give 1:1 D23 a try (7.5:100 stock),on some FP4 film shot in contrasty lighting, later this week.
Regards,
John.

Compensation is only one of the benefits of two-bath D23. I agree that one would get very good compensation with the diluted formula and agitation method you suggest. But would one also get full emulsion speed, or at least an EI as high as with two-bath development? I suspect not because the primary role of the second bath is to develop the shadow densities after the reducer has exhausted itself in the highlights. Something to test in the future.

Sandy King

dancqu said:

I use an 8-80 formula D23 at 1:7 dilution; 120, 500ml.
A few inversions at developer in, 3 or 4 at 1 minute and
the same at 2 minutes intervals; Across 16 minutes.

My guess, the B bath is superfluous using the above
processing. The high dilution with it's consequent rapid
local depletion produces lots of compensation. Dan

Click to expand...

sanking said:

Compensation is only one of the benefits of two-bath D23.
I agree that one would get very good compensation with the
diluted formula and agitation method you suggest. But would
one also get full emulsion speed, or at least an EI as high as
with two-bath development?

I suspect not because the primary role of the second bath
is to develop the shadow densities after the reducer has
exhausted itself in the highlights.
Something to test in the future.

Click to expand...

Testing done; gray card zone exposures plus Tobias
densitometer readings. About a year ago I initiated a thread
reporting the results. Some may remember the thread. IIRC
titled "D-23 1:7 - It Works" or very similar.

Full 100 ISO, Acros 100 with my equipment. Contrast built
slowly. I'll dig up my records and/or find the thread then post.
I was pleasantly surprised with the results. I've now and then
championed the use of highly dilute D-76 and D-23. Dan

Did you make a similar test with divided D23 to compare shadow value densities?

If not, my question is still out there.

Sandy King

dancqu said:

Testing done; gray card zone exposures plus Tobias
densitometer readings. About a year ago I initiated a thread
reporting the results. Some may remember the thread. IIRC
titled "D-23 1:7 - It Works" or very similar.

Full 100 ISO, Acros 100 with my equipment. Contrast built
slowly. I'll dig up my records and/or find the thread then post.
I was pleasantly surprised with the results. I've now and then
championed the use of highly dilute D-76 and D-23. Dan

Click to expand...

sanking said:

Did you make a similar test with divided D23 to
compare shadow value densities? If not, my
question is still out there. Sandy King

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I'm too easily satisfied. I've not tested any divided
developers. Takes some time to test but anyone with
some stock D-23 has a head start. I used 500ml at 1:7
dilution, one roll of Across. Time starts at Developer in;
then 3 inversions, 3 at one minute and 3 again at two
minute intervals; 16 minutes, 73 +/- 1 degree. Dan

Thanks for the details. I will try to find time to do a comparison soon and report results.

Sandy

dancqu said:

I'm too easily satisfied. I've not tested any divided
developers. Takes some time to test but anyone with
some stock D-23 has a head start. I used 500ml at 1:7
dilution, one roll of Across. Time starts at Developer in;
then 3 inversions, 3 at one minute and 3 again at two
minute intervals; 16 minutes, 73 +/- 1 degree. Dan

Click to expand...

sanking said:

Thanks for the details. I will try to find time to do a comparison soon and report results.

Sandy

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Sandy, have you managed to find time for this yet??
I now have some kodalk and am ready to try divided D23.
One problem has sprung up and that is about soln. B.
Exactly how much sodium metaborate should be used? Some say 10gms/li, some 2gms/li and others 40gms/li.
do I make a stock of B and dilute for one shot or reuse stock for a number of films.
Advice welcome.
Regards
John.