[LargeFormat] 5x7 Daylight tank

[Richard Knoppow]

----- Original Message ----- 
From: "LNPhoto" <LNPhoto at twmi.rr.com>
To: "Richard Knoppow" <dickburk at ix.netcom.com>; "f32 Large 
Format Photography Mail List" <largeformat at f32.net>
Sent: Wednesday, April 06, 2005 11:14 AM
Subject: Re: [LargeFormat] 5x7 Daylight tank


>
> On Apr 5, 2005, at 11:00 PM, Richard Knoppow wrote:
>
>>
>> ----- Original Message ----- From: "Edward Meyers" 
>> <aghalide at panix.com>
>> To: "f32 Large Format Photography Mail List" 
>> <largeformat at f32.net>
>> Sent: Tuesday, April 05, 2005 12:07 PM
>> Subject: RE: [LargeFormat] 5x7 Daylight tank
>>
>>
>>> You forget about interlaving sheets in a tray in total 
>>> darkness or visually with an infrared viewing device. Ed
>>>
>>> On Tue, 5 Apr 2005, Frank Filippone wrote:
>>>
>>>> There was made a 5x7 version of the plastic 4x5 tank 
>>>> with the insert for
>>>> holding the film.  I think it was made by Morse or FR 
>>>> or HP/Combi, but I
>>>> forget....  I have never seen one for sale on Ebay.  So 
>>>> maybe it was rarely
>>>> produced.
>>>>
>>   Morse Instrument made a daylight tank that took 
>> standard 5x7 or 4x7 holders. The tank consisted of a 
>> special housing for the holders with a light tight 
>> labrynth at the bottom. The entire assembly was immerced 
>> into standard type tanks and agitated in the usual way 
>> for film hangers by removing and re-immercing it at 
>> intervals. These were made for the military as well as 
>> commercially and at one time were fairly common used. I 
>> missed the last one I saw and have not seen any recently. 
>> Serching eBay for Morse may find one. Morse also made 
>> developing tanks for long rolls of film. There was a size 
>> for 70mm and another for either 35mm or 16mm with a 
>> capacity of 50 feet. The 16mm version was used extensivly 
>> by the Air Force for developing gun camera films.
>>
>>
>
> I have one of these, and while its sized for 5x7, you'll 
> need the 3.5 gallon 8x10 tanks to use it. For me, the 
> Morse tank seems to have a lot of hoops to jump through 
> just to get daylight developing.  I'd rather use the 
> stainless steel racks to hold the neg hangers and stay 
> dark.  They hold a lot more and are easier to clean.
>
> Les

    For sizes larger than 4x5 I think the Morse tank is 
about the only daylight tank ever made. Otherwise one must 
use a drum. I have had some success developing 8x10 in drums 
but it needs a special technique to avoid bromide streaking. 
I have Unicolor and Besler drums, both work, and both have 
ridges that allow access of the chemistry to the back of the 
film. I had only one separator for the Unicolor drum but 
made others from plastic food container lids. The problem I 
had was bromide streaking when the drum was used on a motor 
base. I think the reason is that there is not enough flow of 
the developer to carry reaction products away from a line in 
the direction of rotation. Agitating the drum by hand or by 
taking it off the motor base and agitating sideways 
occasionally will eliminate the streaking. Probably 
different developers are more or less sensitive to this. The 
particular negatives I first noticed the problem on were 
developed in Rodinal 1:50. I am not sure now if the film was 
Plus-X or Agfa APX-100. The steaking showed up on very 
bright specular reflections of the sun from the windows of 
distant buildings. This may not be a problem for subject 
matter without this sort of very dense spot areas but its 
just as well to use a technique to avoid it.
   I also tray develop large negatives. This works well, but 
of course, requires a truely dark room and some care in 
agitation to avoid scratching or gouging if several sheets 
are done at once. Conventional tank lines are also possible 
but take a lot of solution and are not IMO suitable for low 
volume work.
   For 4x5 I use an old Nikor stainless steel tank. This 
works very well but AFAIK, no such tank was ever made for 
larger film and would probably be too large and bulky 
anyway. The Nikor tank takes 12 sheets and uses a liter of 
solution. A 5x7 tank would probably require a half gallon 
and would be rather heavy.
   Probably print drums or BTZS are the best solution for 
small volume work.

---
Richard Knoppow
Los Angeles, CA, USA
dickburk at ix.netcom.com