New to Black and White developing...........

[Horseman]

For scanning you may want a less dense negative for flat bed vs a dedicated film scanner.

One more question esearing, by underexposure or by underdevelopment ?

Thanks

John

[Leigh]

One question , I saw someone on a YT vid rinse the film with water for a minute or 2 prior to commencing a 3 step development to remove the antihalation layer, is this necessary|beneficial?

Hi John,

Most films have an anti-halation coating on the back (away from the emulsion). It is a dense (maybe opaque) layer of dye that prevents light from reflecting off the metal in the camera, back into the emulsion resulting in additional exposure. The effect is called "halation" because it produces an out-of-focus bright area on the print.

It is designed to wash off in any liquid. You can use a pre-wash to do it if you wish, or the developer will do it.

There may be other benefits in specific processing sequences, and it may be contra-indicated in others.

For example, with two-part developers like Diafine, a pre-wash is definitely discouraged since it defeats the normal processing sequence. The first part of the developer is designed to be absorbed into a dry emulsion.

- Leigh

[Horseman]

Thanks Leigh, for the mo I will stick to the simple 3 stage method in that case.

[Mick Fagan]

You may wish to think about the SP-445 film tank, it doesn't hold 6 sheets, only 4 sheets, but in my case, it uses around 465ml of solution (manufacturer states 16 US fluid ounces/475ml), instead of the 1 litre that the MOD54 requires. This may mean the difference if you return home and only need to develop 2 sheets of film but don't until you get enough to justify using 1 litre of solution.

I have used Jobo rotary processing for 4x5" film for around 30 years, I purchased an SP-445 tank when they became available and have been more than happy with it. I have not used the MOD54 unit, so I cannot comment, other than noting the solution quantity requirement.

Mick.

[Horseman]

Thanks Mick, I had already ordered the MOD54 but I do like the SP445 as well so may get one to allow for smaller runs .

Many thanks for all the help and advice everyone,

John

[esearing]

One more question esearing, by underexposure or by underdevelopment ?

Thanks

John

Why would you underexpose film vs use development dilution/time/temp/agitation to control contrast and density? Think about it - what are the consequences of each on shadows, midtones, and highlights?

[Pere Casals]

I've done lot in a bathroom... this is my view. First, I suggest this reading: http://www.ssnpstudents.com/wp/wp-co...m-Cookbook.pdf

It is a bathroom, so a priority is using very low toxic chemicals. Xtol is low toxic, ascorbic acid (Vitamin C) based with some phenidone.

Most fixers are low toxic, but once you have used it... it contains diluted Silver that is toxic in that situation, so try to not drop used fixer around. Silver can be recovered easy from fixer, see here post #9: https://www.photrio.com/forum/thread...9/#post-164354

Most people simply dumps fixer, just know that used fixer contains diluted Silver, so try to not spill it on domestic surfaces too much...


You can use paper developing trays: http://www.largeformatphotography.in...=1#post1419143


For developing in trays at darkroom I'd suggest Xtol 1:2, this is a part of stock developer an 2 parts of water. Each sheet needs a minimum 25ml of Xtol stock for each 4x5 sheet, this is a total 75cc after adding water.

If you use Xtol 1:2 dilution then you will have enough volume 75cc per 4x5 tray yo cover well the sheet, you may use a bit more of 1:2 dilution, some 150ml per sheet.

Here you have the times: https://www.digitaltruth.com/devchar...ch&TempUnits=C

Some tricks:

1) When diluting developer you can adjust temperature very easy. Just measure Xtol stock temperature and adjust temperature of water to be added to make the mix have 20ºC. For example if 100ml Xtol stock is at 22ºC and you are to dilute 1:1, then mix cold and hot tap water until you have water at 18ºC, if you add 100ml of water at 18ºC to 100ml of Xtol at 22ºC you ontain 200ml at 20ºC near exactly. If you are to dilute 1:2, then you have to add 200ml at 19ºC to 100ml of Xtol at 22ºC to obtain 300ml 1:2 dilution at 20ºC...

2) When you transfer the sheet to the stop bath you can open lights (after some 10s) and do the rest with lights open, so you will observe how fixer works.

3) You can use an HEPA purifier like Honeywell 16200E to get rid of dust, this is extremly useful when drying and when scanning.

[Kirk Fry]

The killer is getting even development. Take a few pictures of blank sky and see if your developing procedure is producing even development. It took me two years to discover why Ansel used open trays. :-) And yes you have to have a dark room. Really dark.

[Leigh]

2) When you transfer the sheet to the stop bath you can open lights (after some 10s) and do the rest with lights open, so you will observe how fixer works.

I do not recommend turning the lights on during any processing session.

Doing so kills your eyes' dark adaptation.

- Leigh

[Horseman]

Why would you underexpose film vs use development dilution/time/temp/agitation to control contrast and density? Think about it - what are the consequences of each on shadows, midtones, and highlights?

Now I think about it it may well be a daft question , but it did at least make me think about it...

Expose normally, and "underdevelop" to make the highlights less dense, and the midtones a little less dense and shadows hardly affected if at all ( and not dense in the first place ) , This now makes sense to me if I am on the right track !

Thanks !