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walbergb
4-May-2015, 12:51
I'm about to try my first night shots using 4x5 sheet film-HP5. The scene (a small bridge in the city) will include street lights and will require compensating development to prevent the highlights from blocking up. I plan to make some D-23 developer and a 36% Borax solution as the 2nd bath. I'm not sure of the times and frequency of the two baths. Any advice?

I've read 2-3 minutes in the D-23 with constant agitation followed by 3 minutes in the accelerator with no agitation. Stop and fix as usual. I've also read that the 2-bath process should be repeated with a visual inspection to determine proper development. Or perhaps I am confuded. No, I am confused; that's why I'm asking for your advice/sharing of experiences.

Bob

Taija71A
4-May-2015, 13:10
Bob, the following Articles, will get you started...
*If you have already decided on a Two-Bath D-23 variant.

Divided D-23 Developer.
http://unblinkingeye.com/Articles/DD-23/dd-23.html
http://www.largeformatphotography.info/forum/showthread.php?76904-What-formula-are-you-using-for-Divided-D-23

Stoeckler Two-Bath Film Developer.
http://www.largeformatphotography.info/twobath/

Barry Thornton’s Two-Bath Developer.
http://www.awh-imaging.co.uk/barrythornton/2bath.htm
http://www.photosensitive.ca/wp/archives/115
http://www.apug.org/forums/forum223/33566-thorntons-two-bath.html

However of course, Divided D-23 is not a 'true' divided Film Developer.

Personally, for your intended usage, I would 'perhaps' look at Diafine...
Or even an 'Extreme Compensating' Film Developer instead.

Best regards, -Tim.

walbergb
5-May-2015, 08:48
Thanks for the leads Tim. I found the Unblinking Eye article informative. Proof will be in the pudding. I exposed three sheets last night. Hope to process them tomorrow.

Taija71A
5-May-2015, 09:08
No problem Bob. You are more than welcome.
I am very glad, that you found the article on unblinkingeye... To be of benefit.

If I can be of any other assistance to yourself...
Please feel free to shoot me a PM or an e-Mail (at any time).

Keep up the good work!

Jim Noel
5-May-2015, 09:55
Your time in the accelerator will determine contrast. I sometimes use DD23 mixed similarly to yours and have used times in "B" from 3-20 minutes. Since I usually am looking for a longer scaled negative to use for salt prints 15-20 minutes is not unusual. Your 3 minutes should give you a good point from which to begin. I have used D-23 with a water bath when I need extreme compensation and I actually prefer it for this purpose.

Michael R
6-May-2015, 07:15
Some notes:

In the case of two-solution metol-sulfite + alkali bath developers (Adams, Stoeckler, Leitz, Thornton, Dalzell etc.), the controls are essentially the following:

-Time in bath A: Contrast, and to a small degree, emulsion speed (assuming sufficient time for emulsion saturation)
-Time/agitation in bath B: Emulsion speed
-pH of bath B: Emulsion speed (to a degree), fog

Activity in bath B is complex since it is a function of pH/buffering and diffusion/swell (which also depends on emulsion characterstics). However the most logical course of action is to allow sufficient time in bath B for "completion"/exhaustion. For borax or metaborate, ~5 minutes should generally be sufficient. Not much point in fussing over changes in concentration (ie Thornton), unless very large changes are made in the case of metaborate. Changing to a carbonate alkali will generally increase emulsion speed slightly since development will proceed quickly and exhaust before meaningful amounts of developing agent diffuse out of the emulsion. Fog will also increase.

In all cases the resulting characteristic curve tends to be somewhat straightened.